WO2013085042A1

WO2013085042A1 - Fundus observation device

Info

Publication number: WO2013085042A1
Application number: PCT/JP2012/081816
Authority: WO
Inventors: 林　健史
Original assignee: 株式会社トプコン
Priority date: 2011-12-09
Filing date: 2012-12-07
Publication date: 2013-06-13
Also published as: JPWO2013085042A1

Abstract

Provided is a novel optical system configuration for a fundus observation device. In an embodiment, a fundus observation device has a first optical system for guiding fundus-reflected light of illuminated light to an imaging device, and a second optical system for detecting interference light from interference between reference light and signal light passing through the fundus, and acquires a fundus image using the first optical system and acquires a tomographic image using the second optical system. The first optical system includes an open-hole mirror and an objective lens, and irradiates the fundus via the objective lens with illuminating light reflected by the open-hole mirror and guides fundus-reflected light passing through the objective lens to the imaging device via a hole of the open-hole mirror. The second optical system includes a dichroic mirror for diverting the light path of the signal light from the light path of the first optical system, the dichroic mirror being arranged between an open-hole mirror and an objective lens, and the second optical system irradiates the fundus via the objective lens with the signal light passing through the dichroic mirror and causes the signal light passing through the fundus and the objective lens to interfere with the reference light via the dichroic mirror.

Description

Fundus observation device

The present invention relates to a fundus oculi observation device that acquires an image of the fundus oculi using optical coherence tomography (OCT).

In recent years, OCT that forms an image representing the surface form and internal form of an object to be measured using a light beam from a laser light source or the like has attracted attention. Since OCT has no invasiveness to the human body like X-ray CT, it is expected to be applied particularly in the medical field and the biological field. For example, in the field of ophthalmology, an apparatus for forming an image of the fundus oculi or cornea has been put into practical use.

Patent Document 1 discloses an apparatus to which OCT is applied. In this device, the measuring arm scans an object with a rotating turning mirror (galvanomirror), a reference mirror is installed on the reference arm, and the intensity of the interference light of the light beam from the measuring arm and the reference arm is dispersed at the exit. An interferometer is provided for analysis by the instrument. Further, the reference arm is configured to change the phase of the reference light beam stepwise by a discontinuous value.

The apparatus of Patent Document 1 uses a so-called “Fourier Domain OCT (Fourier Domain OCT)” technique. In other words, a low-coherence beam is irradiated onto the object to be measured, the reflected light and the reference light are superimposed to generate interference light, and the spectral intensity distribution of the interference light is acquired and subjected to Fourier transform. Thus, the form of the object to be measured in the depth direction (z direction) is imaged. This method is also called a spectral domain.

Furthermore, the apparatus described in Patent Document 1 includes a galvanometer mirror that scans a light beam (signal light), thereby forming an image of a desired measurement target region of the object to be measured. This apparatus is configured to scan the light beam only in one direction (x direction) orthogonal to the z direction. An image formed by this apparatus is a two-dimensional tomographic image in the depth direction (z direction) along the scanning direction (x direction) of the light beam.

In Patent Document 2, a plurality of two-dimensional tomographic images in the horizontal direction are formed by scanning (scanning) the signal light in the horizontal direction (x direction) and the vertical direction (y direction), and based on the plurality of tomographic images. A technique for acquiring and imaging three-dimensional tomographic information of a measurement range is disclosed. As this three-dimensional imaging, for example, a method of displaying a plurality of tomographic images side by side in a vertical direction (referred to as stack data or the like), volume data (voxel data) based on the stack data is rendered, and a three-dimensional image is rendered. There is a method of forming.

Patent Documents 3 and 4 disclose other types of OCT apparatuses. In Patent Document 3, the wavelength of light irradiated to a measured object is scanned (wavelength sweep), and interference intensity obtained by superimposing reflected light of each wavelength and reference light is detected to detect spectral intensity distribution. And an OCT apparatus for imaging the form of an object to be measured by performing Fourier transform on the obtained image. Such an OCT apparatus is called a swept source type. The swept source type is a kind of Fourier domain type.

In Patent Document 4, the traveling direction of light is obtained by irradiating the object to be measured with light having a predetermined beam diameter, and analyzing the component of interference light obtained by superimposing the reflected light and the reference light. An OCT apparatus for forming an image of an object to be measured in a cross-section orthogonal to is described. Such an OCT apparatus is called a full-field type or an en-face type.

Patent Document 5 discloses a configuration in which OCT is applied to the ophthalmic field. Prior to the application of OCT, a fundus camera, a slit lamp, or the like was used as an apparatus for observing the eye to be examined (see, for example, Patent Document 6 and Patent Document 7). A fundus camera is a device that shoots the fundus by illuminating the subject's eye with illumination light and receiving the fundus reflection light. A slit lamp is a device that acquires an image of a cross-section of the cornea by cutting off a light section of the cornea using slit light.

An apparatus using OCT has an advantage over a fundus camera or the like in that a high-definition image can be acquired, and further, a tomographic image or a three-dimensional image can be acquired.

Thus, since an apparatus using OCT can be applied to observation of various parts of an eye to be examined and can acquire high-definition images, it has been applied to diagnosis of various ophthalmic diseases.

Japanese Patent Laid-Open No. 11-325849 JP 2002-139421 A JP 2007-24677 A JP 2006-153838 A JP 2008-73099 A JP-A-9-276232 JP 2008-259544 A US Pat. No. 7,400,410

In the conventional fundus oculi observation device, for example, as disclosed in Patent Document 5, the fundus imaging optical path and the OCT are located behind the aperture mirror for fundus imaging (in the direction opposite to the eye to be examined). The optical path for measurement is merged. That is, the signal light is irradiated to the eye to be examined through a hole formed in the aperture mirror, and the backscattered light of the signal light from the fundus is superimposed on the reference light through the same hole. The optical system having such a configuration greatly restricts the expansion of a light beam (signal light) for OCT measurement. As a result, there arise problems that the resolution is limited and it is difficult to improve the interference intensity (improve the image quality).

Furthermore, according to the optical system having such a configuration, since the scanning range of the signal light is limited to the size of the hole, there is a possibility that the signal light to be irradiated to the fundus periphery is kicked by the aperture mirror. In view of the influence of the focusing lens and the like, this problem is particularly remarkable in the eye to be examined having a strong refractive error.

An object of the present invention is to provide a novel configuration of an optical system of a fundus oculi observation device.

In order to achieve the above object, the invention according to claim 1 is directed to a first optical system that irradiates the fundus of the subject's eye with illumination light, guides the fundus reflection light of the illumination light to the imaging device, and a light source. A second optical system that divides light into signal light and reference light, generates interference light by causing the signal light and the reference light to pass through the fundus of the eye to be examined, and detects the interference light; A fundus oculi observation device that acquires a fundus image representing a surface form of the fundus oculi based on a detection result by the imaging device and acquires a tomographic image of the fundus oculi based on a detection result by the second optical system, The first optical system includes a perforated mirror having a hole and an objective lens, irradiates the fundus with the illumination light reflected by the perforated mirror through the objective lens, and the objective The fundus reflection light that has passed through the lens is transmitted through the hole to the imaging device. The second optical system includes a dichroic mirror that is disposed between the aperture mirror and the objective lens and branches the optical path of the signal light from the optical path of the first optical system, and the dichroic mirror Irradiating the fundus with the signal light via a mirror, and causing the signal light via the fundus and the objective lens to interfere with the reference light via the dichroic mirror. To do.
The invention according to claim 2 is the fundus oculi observation device according to claim 1, wherein the dichroic mirror substantially transmits the illumination light and the fundus reflection light, and transmits the signal light. The optical path of the signal light is branched from the optical path of the first optical system by being substantially reflected.
The invention according to claim 3 is the fundus oculi observation device according to claim 2, wherein the dichroic mirror transmits 95% or more of light having a wavelength of 400 nm to 770 nm and transmits light having a wavelength of 790 nm or more. It is configured to reflect 95% or more.
The invention according to claim 4 is the fundus oculi observation device according to any one of claims 1 to 3, wherein each of the first optical system and the second optical system is matched. A focusing lens is provided.

According to the present invention, it is possible to provide a fundus oculi observation device having an optical system having a novel configuration.

It is a schematic diagram showing an example of composition of a fundus oculi observation device concerning an embodiment. It is a schematic diagram showing an example of composition of a fundus oculi observation device concerning an embodiment. It is a schematic block diagram showing an example of composition of a fundus oculi observation device concerning an embodiment. It is a flowchart showing the operation example of the fundus oculi observation device concerning an embodiment.

An example of an embodiment of a fundus oculi observation device according to the present invention will be described in detail with reference to the drawings. The fundus oculi observation device according to the present invention forms a tomographic image or a three-dimensional image of the fundus using OCT. In this specification, images acquired by OCT may be collectively referred to as OCT images. In addition, a measurement operation for forming an OCT image may be referred to as OCT measurement. In addition, it is possible to use suitably the description content of the literature described in this specification as the content of the following embodiment.

In the following embodiment, a fundus oculi observation device that performs OCT measurement of the fundus by applying Fourier domain type OCT using the object to be measured (fundus) as an object to be measured will be described. In particular, the fundus oculi observation device according to the embodiment can acquire both the fundus OCT image and the fundus oculi image using the spectral domain OCT technique, similarly to the device disclosed in Patent Document 5. The configuration according to the present invention can be applied to a fundus oculi observation device using a type other than the spectral domain, for example, a swept source OCT technique. In this embodiment, an apparatus combining an OCT apparatus and a fundus camera will be described. However, this embodiment may be applied to a fundus imaging apparatus other than a fundus camera, such as an SLO (Scanning Laser Ophthalmoscope), a slit lamp, an ophthalmic surgical microscope, and the like. It is also possible to combine an OCT apparatus having the configuration according to the above. In addition, the configuration according to this embodiment can be incorporated into a single OCT apparatus.

[Constitution]
As shown in FIGS. 1 and 2, the fundus oculi observation device 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The retinal camera unit 2 has almost the same optical system as a conventional retinal camera. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus. The arithmetic control unit 200 includes a computer that executes various arithmetic processes and control processes.

[Fundus camera unit]
The fundus camera unit 2 shown in FIG. 1 is provided with an optical system for obtaining a two-dimensional image (fundus image) representing the surface form of the fundus oculi Ef of the eye E to be examined. The fundus image includes an observation image and a captured image. The observation image is a monochrome moving image formed at a predetermined frame rate using near infrared light, for example. The captured image may be, for example, a color image obtained by flashing visible light, or a monochrome still image using near infrared light or visible light as illumination light. The fundus camera unit 2 may be configured to be able to acquire images other than these, such as a fluorescein fluorescent image, an indocyanine green fluorescent image, a spontaneous fluorescent image, and the like.

The fundus camera unit 2 is provided with a chin rest and a forehead for supporting the subject's face. Further, the fundus camera unit 2 is provided with an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the fundus oculi Ef with illumination light. The photographing optical system 30 guides the fundus reflection light of the illumination light to an imaging device (CCD image sensor (sometimes simply referred to as a CCD) 35, 38). The imaging optical system 30 guides the signal light from the OCT unit 100 to the fundus oculi Ef and guides the signal light passing through the fundus oculi Ef to the OCT unit 100.

The observation light source 11 of the illumination optical system 10 is composed of, for example, a halogen lamp. The light (observation illumination light) output from the observation light source 11 is reflected by the reflection mirror 12 having a curved reflection surface, passes through the condensing lens 13, passes through the visible cut filter 14, and is converted into near infrared light. Become. Further, the observation illumination light is once converged in the vicinity of the photographing light source 15, reflected by the mirror 16, and passes through the

relay lenses

17 and 18, the diaphragm 19 and the relay lens 20. Then, the observation illumination light is reflected at the peripheral portion (region around the hole portion) of the aperture mirror 21, passes through the dichroic mirror 46, and is refracted by the objective lens 22 to illuminate the fundus oculi Ef. An LED (Light Emitting Diode) can also be used as the observation light source.

The fundus reflection light of the observation illumination light is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through the hole formed in the central region of the perforated mirror 21, passes through the dichroic mirror 55, and is a focusing lens. It is reflected by the mirror 32 via 31. Further, the fundus reflection light passes through the half mirror 40, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the CCD image sensor 35 by the condenser lens 34. The CCD image sensor 35 detects fundus reflected light at a predetermined frame rate, for example. On the display device 3, an image (observation image) based on fundus reflection light detected by the CCD image sensor 35 is displayed. When the photographing optical system is focused on the anterior segment, an observation image of the anterior segment of the eye E is displayed.

The photographing light source 15 is constituted by, for example, a xenon lamp. The light (imaging illumination light) output from the imaging light source 15 is applied to the fundus oculi Ef through the same path as the observation illumination light. The fundus reflection light of the imaging illumination light is guided to the dichroic mirror 33 through the same path as that of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37 of the CCD image sensor 38. An image is formed on the light receiving surface. On the display device 3, an image (captured image) based on fundus reflection light detected by the CCD image sensor 38 is displayed. Note that the display device 3 that displays the observation image and the display device 3 that displays the captured image may be the same or different. In addition, when similar imaging is performed by illuminating the eye E with infrared light, an infrared captured image is displayed. It is also possible to use an LED as a photographing light source.

The LCD (Liquid Crystal Display) 39 displays a fixation target and an eyesight measurement index. The fixation target is an index for fixing the eye E to be examined, and is used at the time of fundus photographing or OCT measurement.

A part of the light output from the LCD 39 is reflected by the half mirror 40, reflected by the mirror 32, passes through the focusing lens 31 and the dichroic mirror 55, passes through the hole of the perforated mirror 21, and is dichroic. The light passes through the mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef.

The fixation position of the eye E can be changed by changing the display position of the fixation target on the screen of the LCD 39. As the fixation position of the eye E, for example, a position for acquiring an image centered on the macular portion of the fundus oculi Ef, or a position for acquiring an image centered on the optic disc as in the case of a conventional fundus camera And a position for acquiring an image centered on the fundus center between the macula and the optic disc. It is also possible to arbitrarily change the display position of the fixation target.

Furthermore, the fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60 as in the conventional fundus camera. The alignment optical system 50 generates an index (alignment index) for performing alignment (alignment) of the apparatus optical system with respect to the eye E. The focus optical system 60 generates an index (split index) for focusing on the fundus oculi Ef.

The light (alignment light) output from the LED 51 of the alignment optical system 50 is reflected by the dichroic mirror 55 via the

apertures

52 and 53 and the relay lens 54, passes through the hole of the perforated mirror 21, and reaches the dichroic mirror 46. And is projected onto the cornea of the eye E by the objective lens 22.

The corneal reflection light of the alignment light passes through the objective lens 22, the dichroic mirror 46 and the hole, part of which passes through the dichroic mirror 55, passes through the focusing lens 31, is reflected by the mirror 32, and is half mirror 40 is reflected by the dichroic mirror 33 and projected onto the light-receiving surface of the CCD image sensor 35 by the condenser lens 34. The light reception image (alignment index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The user performs alignment by performing the same operation as that of a conventional fundus camera. Further, the arithmetic control unit 200 may perform alignment by analyzing the position of the alignment index and moving the optical system (auto-alignment function).

When performing the focus adjustment, the reflecting surface of the reflecting rod 67 is obliquely provided on the optical path of the illumination optical system 10. The light (focus light) output from the LED 61 of the focus optical system 60 passes through the relay lens 62, is separated into two light beams by the split indicator plate 63, passes through the two-hole aperture 64, and is reflected by the mirror 65, The light is focused on the reflecting surface of the reflecting bar 67 by the condenser lens 66 and reflected. Further, the focus light passes through the relay lens 20, is reflected by the perforated mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef.

The fundus reflection light of the focus light is detected by the CCD image sensor 35 through the same path as the corneal reflection light of the alignment light. A light reception image (split index) by the CCD image sensor 35 is displayed on the display device 3 together with the observation image. The arithmetic and control unit 200 analyzes the position of the split index and moves the focusing lens 31 and the focus optical system 60 to perform focusing as in the conventional case (autofocus function). Alternatively, focusing may be performed manually while visually checking the split indicator.

The dichroic mirror 46 is provided at a position between the perforated mirror 21 and the objective lens 22, and branches the optical path for OCT measurement from the optical path for fundus imaging. The dichroic mirror 46 substantially transmits the fundus photographing light and substantially reflects the light in the wavelength band used for OCT measurement. “Substantially” indicates that it is not necessary to transmit or reflect all the light in the wavelength band, and an error that does not affect fundus imaging or OCT measurement is allowed. The transmission / reflection characteristics of the dichroic mirror 46 are set according to the wavelength of the fundus photographing light used by the fundus oculi observation device 1 and the wavelength of the OCT measurement light (signal light LS). For example, the dichroic mirror 46 is configured to transmit 95% or more of light having a wavelength of 400 nm to 770 nm used for fundus photography and to reflect 95% or more of light having a wavelength of 790 nm or more used for OCT measurement. The characteristics of the dichroic mirror 46 are not limited to this numerical example.

In this optical path for OCT measurement, a collimator lens unit 40, an optical path length changing unit 41, a galvano scanner 42, a focusing lens 43, a mirror 44, and a relay lens 45 are provided in this order from the OCT unit 100 side. It has been.

The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1, and changes the optical path length of the optical path for OCT measurement. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E or adjusting the interference state. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the corner cube.

The galvano scanner 42 changes the traveling direction of light (signal light LS) passing through the optical path for OCT measurement. Thereby, the fundus oculi Ef can be scanned with the signal light LS. The galvano scanner 42 includes, for example, a galvano mirror that scans the signal light LS in the x direction, a galvano mirror that scans in the y direction, and a mechanism that drives these independently. Thereby, the signal light LS can be scanned in an arbitrary direction on the xy plane.

[OCT unit]
An example of the configuration of the OCT unit 100 will be described with reference to FIG. The OCT unit 100 is provided with an optical system for acquiring an OCT image of the fundus oculi Ef. This optical system has the same configuration as a conventional spectral domain type OCT apparatus. That is, this optical system divides low-coherence light into reference light and signal light, and generates interference light by causing interference between the signal light passing through the fundus oculi Ef and the reference light passing through the reference optical path. It is configured to detect spectral components. This detection result (detection signal) is sent to the arithmetic control unit 200.

In the case of a swept source type OCT apparatus, a wavelength swept light source is provided instead of a light source that outputs a low coherence light source, and an optical member that spectrally decomposes interference light is not provided. In general, for the configuration of the OCT unit 100, a known technique according to the type of optical coherence tomography can be arbitrarily applied.

The light source unit 101 outputs a broadband low-coherence light L0. The low coherence light L0 includes, for example, a near-infrared wavelength band (about 800 nm to 900 nm) and has a temporal coherence length of about several tens of micrometers. Note that near-infrared light having a wavelength band invisible to the human eye, for example, a center wavelength of about 1040 to 1060 nm, may be used as the low-coherence light L0.

The light source unit 101 includes a super luminescent diode (Super Luminescent Diode: SLD), an LED, and an optical output device such as an SOA (Semiconductor Optical Amplifier).

The low coherence light L0 output from the light source unit 101 is guided to the fiber coupler 103 by the optical fiber 102, and is divided into the signal light LS and the reference light LR.

The reference light LR is guided by the optical fiber 104 and reaches an optical attenuator (attenuator) 105. The optical attenuator 105 automatically adjusts the amount of the reference light LR guided to the optical fiber 104 under the control of the arithmetic control unit 200 using a known technique. The reference light LR whose light amount has been adjusted by the optical attenuator 105 is guided by the optical fiber 104 and reaches the polarization adjuster (polarization controller) 106. The polarization adjuster 106 is, for example, a device that adjusts the polarization state of the reference light LR guided in the optical fiber 104 by applying a stress from the outside to the optical fiber 104 in a loop shape. The configuration of the polarization adjuster 106 is not limited to this, and any known technique can be used. The reference light LR whose polarization state is adjusted by the polarization adjuster 106 reaches the fiber coupler 109.

The signal light LS generated by the fiber coupler 103 is guided by the optical fiber 107 and converted into a parallel light beam by the collimator lens unit 105. Further, the signal light LS reaches the dichroic mirror 46 via the optical path length changing unit 41, the galvano scanner 42, the focusing lens 43, the mirror 44, and the relay lens 45. Then, the signal light LS is reflected by the dichroic mirror 46, refracted by the objective lens 11, and irradiated onto the fundus oculi Ef. The signal light LS is scattered (including reflection) at various depth positions of the fundus oculi Ef. The backscattered light of the signal light LS from the fundus oculi Ef travels in the same direction as the forward path in the reverse direction, is guided to the fiber coupler 103, and reaches the fiber coupler 109 via the optical fiber 108.

The fiber coupler 109 causes the backscattered light of the signal light LS to interfere with the reference light LR that has passed through the fiber coupler 104. The interference light LC generated thereby is guided by the optical fiber 110 and emitted from the emission end 111. Further, the interference light LC is converted into a parallel light beam by the collimator lens 112, dispersed (spectral decomposition) by the diffraction grating 113, condensed by the condenser lens 114, and projected onto the light receiving surface of the CCD image sensor 115. The diffraction grating 118 shown in FIG. 2 is a transmission type, but other types of spectroscopic elements such as a reflection type diffraction grating can also be used.

The CCD image sensor 115 is a line sensor, for example, and detects each spectral component of the split interference light LC and converts it into electric charges. The CCD image sensor 115 accumulates this electric charge, generates a detection signal, and sends it to the arithmetic control unit 200.

In this embodiment, a Michelson type interferometer is used, but any type of interferometer such as a Mach-Zehnder type can be appropriately used. Further, in place of the CCD image sensor, another form of image sensor, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or the like can be used.

The OCT unit 100 is further provided with an optical fiber 120, a polarizing plate 122, and a detection element 123. One end of the optical fiber 120 is connected to the fiber coupler 109. The polarizing plate 122 is provided at the subsequent stage of the emission end 121 at the other end of the optical fiber 120. The polarizing plate 122 is a polarizer that transmits only light polarized in a specific direction. The polarizing plate 122 rotates upon receiving a driving force from the actuator 122A. Thereby, the polarization direction of the transmitted light changes. The detection element 123 detects light transmitted through the polarizing plate 122.

[Calculation control unit]
The configuration of the arithmetic control unit 200 will be described. The arithmetic control unit 200 analyzes the detection signal input from the CCD image sensor 115 and forms an OCT image of the fundus oculi Ef. The arithmetic processing for this is the same as that of a conventional spectral domain type OCT apparatus.

The arithmetic control unit 200 controls each part of the fundus camera unit 2, the display device 3, and the OCT unit 100. For example, the arithmetic control unit 200 displays an OCT image of the fundus oculi Ef on the display device 3.

As the control of the fundus camera unit 2, the arithmetic control unit 200 controls the operation of the observation light source 11, the imaging light source 15 and the

LEDs

51 and 61, the operation control of the LCD 39, the movement control of the focusing

lenses

31 and 43, and the reflector 67. Movement control, movement control of the focus optical system 60, movement control of the optical path length changing unit 41, operation control of the galvano scanner 42, and the like are performed.

As the control of the OCT unit 100, the arithmetic control unit 200 controls the operation of the light source unit 101, the operation control of the optical attenuator 105, the operation control of the polarization adjuster 106, the operation control of the CCD image sensor 115, and the polarizing plate 122. Operation control of the (actuator 122A) is performed.

The arithmetic control unit 200 includes, for example, a microprocessor, a RAM, a ROM, a hard disk drive, a communication interface, and the like, as in a conventional computer. A computer program for controlling the fundus oculi observation device 1 is stored in a storage device such as a hard disk drive. The arithmetic control unit 200 may include various circuit boards, for example, a circuit board for forming an OCT image. The arithmetic control unit 200 may include an operation device (input device) such as a keyboard and a mouse, and a display device such as an LCD.

The fundus camera unit 2, the display device 3, the OCT unit 100, and the calculation control unit 200 may be configured integrally (that is, in a single housing) or separated into two or more cases. It may be.

[Control system]
The configuration of the control system of the fundus oculi observation device 1 will be described with reference to FIG.

(Control part)
The control system of the fundus oculi observation device 1 is configured around the control unit 210. The control unit 210 includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, communication interface, and the like. The control unit 210 is provided with a main control unit 211 and a storage unit 212.

(Main control unit)
The main control unit 211 performs the various controls described above. In particular, the main control unit 211 controls the focusing drive unit 31A, the optical path length changing unit 41 and the galvano scanner 42 of the fundus camera unit 2, and further the light source unit 101, the optical attenuator 105 and the polarization adjuster 106 of the OCT unit 100. To do.

The focusing drive unit 31A moves the focusing lens 31 in the optical axis direction. Thereby, the focus position of the photographic optical system 30 is changed. The main control unit 211 can also move an optical system provided in the fundus camera unit 2 in a three-dimensional manner by controlling an optical system drive unit (not shown). This control is used in alignment and tracking. Tracking is to move the apparatus optical system in accordance with the eye movement of the eye E. When tracking is performed, alignment and focusing are performed in advance. Tracking is a function of maintaining a suitable positional relationship in which the alignment and focus are achieved by causing the position of the apparatus optical system to follow the eye movement.

Further, the main control unit 211 performs a process of writing data to the storage unit 212 and a process of reading data from the storage unit 212.

(Memory part)
The storage unit 212 stores various data. Examples of the data stored in the storage unit 212 include OCT image image data, fundus image data, and examined eye information. The eye information includes information about the subject such as patient ID and name, and information about the eye such as left / right eye identification information. The storage unit 212 stores various programs and data for operating the fundus oculi observation device 1.

(Image forming part)
The image forming unit 220 forms tomographic image data of the fundus oculi Ef based on the detection signal from the CCD image sensor 115. This process includes processes such as noise removal (noise reduction), filter processing, FFT (Fast Fourier Transform), and the like, as in the conventional spectral domain type optical coherence tomography. In the case of another type of OCT apparatus, the image forming unit 220 executes a known process corresponding to the type.

The image forming unit 220 includes, for example, the circuit board described above. In this specification, “image data” and “image” based thereon may be identified.

(Image processing unit)
The image processing unit 230 performs various types of image processing and analysis processing on the image formed by the image forming unit 220. For example, the image processing unit 230 executes various correction processes such as image brightness correction and dispersion correction. The image processing unit 230 performs various types of image processing and analysis processing on the image (fundus image, anterior eye image, etc.) obtained by the fundus camera unit 2.

The image processing unit 230 executes known image processing such as interpolation processing for interpolating pixels between tomographic images to form image data of a three-dimensional image of the fundus oculi Ef. Note that the image data of a three-dimensional image means image data in which pixel positions are defined by a three-dimensional coordinate system. As image data of a three-dimensional image, there is image data composed of voxels arranged three-dimensionally. This image data is called volume data or voxel data. When displaying an image based on volume data, the image processing unit 230 performs a rendering process (such as volume rendering or MIP (Maximum Intensity Projection)) on the volume data, and views the image from a specific line-of-sight direction. Image data of a pseudo three-dimensional image is formed. This pseudo three-dimensional image is displayed on a display device such as the display unit 240A.

It is also possible to form stack data of a plurality of tomographic images as image data of a three-dimensional image. The stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines. That is, stack data is image data obtained by expressing a plurality of tomographic images originally defined by individual two-dimensional coordinate systems by one three-dimensional coordinate system (that is, by embedding them in one three-dimensional space). is there.

The image processing unit 230 that functions as described above includes, for example, the aforementioned microprocessor, RAM, ROM, hard disk drive, circuit board, and the like. In a storage device such as a hard disk drive, a computer program for causing the microprocessor to execute the above functions is stored in advance.

(User interface)
The user interface 240 includes a display unit 240A and an operation unit 240B. The display unit 240A includes the display device of the arithmetic control unit 200 and the display device 3 described above. The operation unit 240B includes the operation device of the arithmetic control unit 200 described above. The operation unit 240B may include various buttons and keys provided on the housing of the fundus oculi observation device 1 or outside. For example, when the fundus camera unit 2 has a housing similar to that of a conventional fundus camera, the operation unit 240B may include a joystick, an operation panel, or the like provided on the housing. The display unit 240 </ b> A may include various display devices such as a touch panel monitor provided in the housing of the fundus camera unit 2.

Note that the display unit 240A and the operation unit 240B do not need to be configured as individual devices. For example, a device in which a display function and an operation function are integrated, such as a touch panel monitor, can be used. In that case, the operation unit 240B includes the touch panel display and a computer program. The operation content for the operation unit 240B is input to the control unit 210 as an electrical signal. Further, operations and information input may be performed using a graphic user interface (GUI) displayed on the display unit 240A and the operation unit 240B.

[Signal light scanning and OCT images]
Here, the scanning of the signal light LS and the OCT image will be described.

Examples of the scanning mode of the signal light LS by the fundus oculi observation device 1 include a horizontal scan, a vertical scan, a cross scan, a radiation scan, a circle scan, a concentric scan, and a spiral (vortex) scan. These scanning modes are selectively used as appropriate in consideration of the observation site of the fundus, the analysis target (such as retinal thickness), the time required for scanning, the precision of scanning, and the like.

The horizontal scan is to scan the signal light LS in the horizontal direction (x direction). The horizontal scan also includes an aspect in which the signal light LS is scanned along a plurality of horizontal scanning lines arranged in the vertical direction (y direction). In this aspect, it is possible to arbitrarily set the scanning line interval. Further, the above-described three-dimensional image can be formed by sufficiently narrowing the interval between adjacent scanning lines (three-dimensional scanning). The same applies to the vertical scan.

The cross scan scans the signal light LS along a cross-shaped trajectory composed of two linear trajectories (straight trajectories) orthogonal to each other. In the radiation scan, the signal light LS is scanned along a radial trajectory composed of a plurality of linear trajectories arranged at a predetermined angle. The cross scan is an example of a radiation scan.

The circle scan scans the signal light LS along a circular locus. In the concentric scan, the signal light LS is scanned along a plurality of circular trajectories arranged concentrically around a predetermined center position. A circle scan is an example of a concentric scan. In the helical scan, the signal light LS is scanned along a spiral (spiral) trajectory while gradually reducing (or increasing) the radius of rotation.

Since the galvano scanner 42 is configured to scan the signal light LS in directions orthogonal to each other, the signal light LS can be scanned independently in the x direction and the y direction, respectively. Further, by simultaneously controlling the directions of the two galvanometer mirrors included in the galvano scanner 42, the signal light LS can be scanned along an arbitrary locus on the xy plane. Thereby, various scanning modes as described above can be realized.

By scanning the signal light LS in the above-described manner, a tomographic image on a plane stretched by the direction along the scanning line (scanning locus) and the fundus depth direction (z direction) can be acquired. In addition, the above-described three-dimensional image can be acquired particularly when the scanning line interval is narrow.

The region on the fundus oculi Ef to be scanned with the signal light LS as described above, that is, the region on the fundus oculi Ef to be subjected to OCT measurement is referred to as a scanning region. The scanning area in the three-dimensional scan is a rectangular area in which a plurality of horizontal scans are arranged. The scanning area in the concentric scan is a disk-shaped area surrounded by the locus of the circular scan with the maximum diameter. In addition, the scanning area in the radial scan is a disk-shaped (or polygonal) area connecting both end positions of each scan line.

[Operation]
The operation of the fundus oculi observation device 1 will be described. FIG. 4 shows an example of the operation of the fundus oculi observation device 1.

(S1: Alignment / Focus)
First, a near-infrared moving image of the fundus oculi Ef is acquired by continuously illuminating the fundus oculi Ef with illumination light from the observation light source 11 (which becomes near-infrared light by the visible cut filter 14). This near-infrared moving image is obtained in real time until the continuous illumination ends. Further, the control unit 210 projects the alignment index by the alignment optical system 50 and the split index by the focus optical system 60 onto the eye E. The control unit 210 or the user performs alignment using the alignment index, and further performs focusing using the split index.

(S2: The polarization state adjustment process is started)
Upon completion of alignment and focusing, the control unit 210 causes the fundus oculi observation device 1 to start polarization state adjustment processing.

(S3: block the signal light path)
In the adjustment process of the polarization state, first, the control unit 210 controls the galvano scanner 42 to block the optical path (signal optical path) of the signal light LS. Blocking the signal light path means preventing the signal light LS (its backscattered light) from reaching the detection element 123. In this embodiment, the signal light path between the eye E and the fiber coupler 109 may be blocked. As an example of a method for blocking the signal optical path, there is a method in which the orientation of at least one of the two galvanometer mirrors constituting the galvano scanner 42 is largely changed from the neutral position. It is also possible to block the signal light path by providing a shutter in the signal light path.

(S4: Output light for OCT measurement)
Next, the control unit 210 controls the light source unit 101 to output the low coherence light L0. Since the signal light path is blocked, the detection element 123 detects the reference light LR that has passed through the optical fiber 104.

(S5: The polarization state of the reference light is detected)
The controller 210 changes the polarization state of the reference light LR that passes through the polarizing plate 122 by controlling the actuator 122A to rotate the polarizing plate 122. The detection element 123 detects the reference light LR in a polarization state corresponding to the rotation position of the polarizing plate 122. Accordingly, the detection element 123 detects the reference light LR in the polarization state with respect to each of the plurality of rotation positions of the polarizing plate 122. The detection result corresponding to each rotational position is sent to the control unit 210 as an electrical signal. The control unit 210 obtains the detection intensity of the reference light LR based on each detection result. This detected intensity is, for example, the signal intensity of the electrical signal.

On the other hand, since the control unit 210 rotates the polarizing plate 122, the control unit 210 recognizes the rotational position of the polarizing plate 122 at each detection timing by the detection element 123. The controller 210 associates the detected intensity of the reference light LR with the rotational position of the polarizing plate 122. The rotation position of the polarizing plate 122 is, for example, a rotation angle with respect to a reference position in rotation. The control unit 210 stores the associated detected intensity and rotational position in the storage unit 212.

Here, the detection of the intensity of the reference light LR at a plurality of rotation positions may be performed while continuously rotating the polarizing plate 122 or may be performed while rotating it intermittently.

(S6: Specify the polarization state of the reference light)
The controller 210 selects a predetermined one from the detected intensities of the reference light LR acquired in step 5. The selection target includes the maximum value of these detection intensities. This maximum value corresponds to the polarization state of the reference light LR. Note that instead of the maximum value (or together with the maximum value), another value of the detection intensity may be selected. Another example is a minimum value. Even when a value other than the maximum value is selected, it is possible to adjust the polarization state in the same manner as described later for the maximum value.

(S7: Release the blocking of the signal light path)
Next, the control unit 210 releases the blocking of the signal light path. When using the galvano scanner 42, for example, the control unit 210 returns the galvano mirror whose direction has been changed in step 3 to the neutral position. When using a shutter, the control unit 210 switches the shutter from the closed state to the open state.

(S8: The reference light path is blocked and the polarization state of the signal light is detected)
Subsequently, the control unit 210 blocks the optical path (reference optical path) of the reference light LR. In this embodiment, the optical path is blocked at any position of the optical fiber 104. As an example, the control unit 210 controls the optical attenuator 105 so that the intensity of the reference light LR passing therethrough becomes zero. Thereby, only the signal light LS (its backscattered light) is projected onto the detection element 123. As in the case of the reference light LR, the control unit 210 obtains a predetermined value (maximum value, minimum value, etc.) of the detected intensity of the signal light LS and the rotational position of the polarizing plate 122. This information corresponds to the polarization state of the signal light LS.

(S9: Adjust polarization state)
Next, the control unit 210 adjusts the polarization state of the reference light LR based on the polarization state of the reference light LR identified in Step 6 and the polarization state of the signal light LS identified in Step 8. This process includes a process of determining the setting state of the polarization adjuster 106 and a process of controlling the polarization adjuster 106 based on the determination result.

In the former process, for example, the setting state of the polarization adjuster 106 that realizes the polarization state of the reference light LR that maximizes the intensity of the interference light LC is obtained. In order to maximize the intensity of the interference light LC, the polarization states of the reference light LR and the signal light LS may be matched. The coincidence of the polarization states includes matching the polarization directions (polarization angles) of both lights. In addition to this, it is desirable to obtain the matching deflection direction so that the intensities of both lights are as large as possible. At this time, not only the polarization state selected from a plurality of options in Steps 6 and 10, but also these options (that is, distribution information of detected intensity according to the rotational position of the polarizing plate 122) may be considered. Further, related information relating the rotation position of the polarizing plate 122 and the setting state of the polarization adjuster 106 is acquired in advance and stored in the storage unit 212, and the setting state associated with the desired rotation angle is related. It is desirable to be configured to obtain from information.

When the setting state of the polarization controller 106 is determined, the control unit 210 puts the polarization controller 106 into this setting state. In this embodiment, since the polarization state is adjusted by shielding the reference optical path, the polarization state of the reference light LR is not immediately changed by this adjustment. The “adjustment of” includes such a case (for example, a case where the polarization state of the reference light LR passing through the reference optical path is changed after the blocking state is released).

(S10: Release the blocking of the reference optical path and perform OCT measurement)
Subsequently, the control unit 210 releases the blocking of the reference optical path. As a result, both the backscattered light of the signal light LS from the fundus oculi Ef and the reference light LR reach the fiber coupler 109 to generate interference light LC, and the CCD image sensor 115 detects the spectral component. The control unit 210 controls the galvano scanner 42 to scan the fundus oculi Ef with the signal light LS. The CCD image sensor 115 detects the spectral component of the interference light LC corresponding to each scan position. Based on these detection results, the image forming unit 220 forms a tomographic image of the fundus oculi Ef corresponding to this scan pattern.

[effect]
The effect of the fundus oculi observation device 1 will be described.

The fundus oculi observation device 1 has a first optical system for fundus imaging and a second optical system for OCT measurement. The first optical system includes an illumination optical system 10 that irradiates the fundus oculi Ef of the eye E to be examined and an imaging optical system 30 that guides the fundus reflection light of the illumination light to the imaging devices (CCD image sensors 35 and 38). Including. The second optical system divides the light L0 from the light source unit 101 into the signal light LS and the reference light LR, and causes the signal light LS passing through the fundus oculi Ef to interfere with the reference light LR to generate interference light LC. To detect. The fundus oculi observation device 1 acquires a fundus image representing the surface form of the fundus oculi Ef based on the detection results of the

CCD image sensors

35 and 38, and obtains a tomographic image of the fundus oculi Ef based on the detection result of the second optical system. get.

Further, the first optical system for photographing the fundus includes a perforated mirror 21 having a hole and an objective lens 22. The first optical system irradiates the fundus oculi Ef with the illumination light reflected by the aperture mirror 21 via the objective lens 22, and the fundus reflection light of the illumination light via the objective lens 22 is the aperture mirror. It is configured to lead to the

CCD image sensors

35 and 38 through 21 holes.

Also, the second optical system for OCT measurement includes a dichroic mirror 46 that branches the optical path of the signal light LS from the optical path of the first optical system. The dichroic mirror 46 is disposed between the perforated mirror 21 and the objective lens. Then, the second optical system irradiates the fundus oculi Ef with the signal light LS via the dichroic mirror 46 via the objective lens 22 and the dichroic mirror 46 with the signal light LS via the fundus oculi Ef and the objective lens 22. Via the reference light LR.

The dichroic mirror 46 substantially transmits the fundus photographing illumination light and its fundus reflection light, and substantially reflects the signal light LS, whereby the optical path of the signal light LS from the optical path of the first optical system. May be configured to be branched. As a specific example, the dichroic mirror 46 is configured to transmit 95% or more of light with a wavelength of 400 nm to 770 nm used for fundus photography and reflect 95% or more of light with a wavelength of 790 nm or more used for OCT measurement. It's okay.

According to the fundus oculi observation device 1 to which the optical system having such a configuration is applied, the signal light LS can be transmitted and received without passing through the hole of the aperture mirror 21. That is, the signal light is applied to the fundus oculi Ef without passing through the hole formed in the aperture mirror 21, and the backscattered light of the signal light LS from the fundus Ef passes through the aperture of the aperture mirror 21. Without being superimposed on the reference light LR. Therefore, the size of the hole portion of the perforated mirror 21 does not limit the expansion of the signal light LS, and conventional problems such as resolution limitation and interference intensity (image quality) limitation are solved.

Furthermore, according to the fundus oculi observation device 1, the scanning range of the signal light LS is not limited by the size of the hole portion of the perforated mirror 21. Therefore, the conventional problem that the signal light LS to be irradiated to the fundus periphery is kicked by the perforated mirror 21 can be solved. This is the same even when the degree of refractive error of the eye E is strong.

In the fundus oculi observation device 1, a focusing lens is provided in each of the first optical system and the second optical system. That is, the fundus oculi observation device 1 includes a focusing lens 31 for fundus imaging and a focusing lens 43 for OCT measurement.

Note that a conventional fundus oculi observation device as disclosed in Patent Document 5 (Japanese Patent Laid-Open No. 2008-73099) shares the same focusing lens for fundus imaging and OCT measurement. Considering that the wavelength of light for fundus imaging (visible light, etc.) is different from the wavelength of light for OCT measurement (near infrared light, etc.), the optimal focus position for fundus imaging and the OCT measurement The optimum focus position does not exactly match. Therefore, according to the conventional fundus oculi observation device, if the focusing lens is set to the optimum focus position for fundus photography, OCT measurement cannot be performed in the optimum focus state, and conversely, the optimum focus position for OCT measurement is obtained. When the focusing lens was combined, fundus photography could not be performed in an optimal focus state.

On the other hand, by providing separately the focusing lens 31 for fundus imaging and the focusing lens 43 for OCT measurement as in this embodiment, it is possible to perform both fundus imaging and OCT measurement in an optimal focus state. It is. In particular, this embodiment is considered effective when fundus imaging and OCT measurement are performed in parallel.

[Modification]
The configuration described above is merely an example for favorably implementing the present invention. Therefore, arbitrary modifications (omitted, replacement, addition, etc.) within the scope of the present invention can be made as appropriate.

(Modification 1)
In order to obtain an accurate image using OCT, it is necessary to match the polarization states of the reference light and the signal light. Factors that change the polarization state include the environment (temperature, humidity, etc.) and displacement of the device structure due to transportation, and the polarization characteristics of the object to be measured itself (eye polarization characteristics in ophthalmology).

In conventional devices, a fixed polarization adjuster (polarization controller) is provided in the optical path to adjust the polarization state and maintain the polarization state, or a wave plate is provided in the optical path as appropriate. The polarization state was adjusted by rotating.

However, there are various ways of changing the polarization state, and since it varies from time to time, it is extremely difficult to always match the polarization state of the reference light and the signal light completely.

In addition, the conventional polarization adjustment was performed so that the intensity of the interference light detection result (interference signal) was monitored and maximized, but there are other factors that change the intensity of the interference signal besides the polarization state. To do. For example, the intensity of the interference signal is also changed by the state of alignment, the amount of light used for measurement, the vignetting of light, and the change of the signal according to the depth position. Therefore, it is difficult to optimize the polarization state with reference to the intensity of the interference signal.

The above embodiment is an example for solving such a problem. That is, the fundus oculi observation device 1 generates the interference light LC by superimposing the signal light LS passing through the object to be measured (fundus Ef) on the reference light LR, and generates an image of the fundus oculi Ef based on the detection result of the interference light. It functions as an OCT apparatus to be formed. The fundus oculi observation device 1 includes a detection unit, an adjustment unit, and a formation unit.

The detection unit detects the polarization state of the reference light LR and the polarization state of the signal light LS. The detection unit includes a polarizing plate 122, an actuator 122 </ b> A, a detection element 123, and a control unit 210. The polarizing plate 122 is provided after the fiber coupler 109 (superimposing member) that superimposes the signal light LS on the reference light LR. The actuator 122A is a mechanism that rotates the polarizing plate. The detection element 123 detects light that has passed through the polarizing plate. The controller 210 associates the intensity of the reference light LR detected by the detection element 123 with the rotational position of the polarizing plate 122.

The adjusting unit adjusts the polarization state of the reference light LR based on the detection result of the polarization state of the reference light LR. The adjustment unit includes the control unit 210 and the polarization adjuster 106. The polarization adjuster 106 is an example of a mechanism that changes the polarization state. Based on the detection result of the polarization state of the reference light LR and the signal light LS, the control unit 210 determines the setting state of the polarization adjuster 106 that maximizes the intensity of the reference light LR, and the polarization is determined based on the determination result. By controlling the adjuster 106, the polarization state of the reference light LR is adjusted.

The forming unit forms an image of the fundus oculi Ef based on the detection result of the interference light LC obtained by superimposing the reference light LR and the signal light LS after the polarization state of the reference light LR is adjusted.

Such a fundus oculi observation device 1 can actually detect the polarization state of the reference light LR and the signal light LS, and adjust the intensity of the interference light LC based on the detection result. Accordingly, it is possible to match the polarization states of the reference light LR and the signal light LS at the present time.

Further, unlike the conventional technique that monitors the intensity of interference light that is affected by various factors other than the polarization state, the intensity of the reference light LR and the signal light LS accompanying the change in the polarization state is monitored, and the intensity of the interference light LC Is optimized, that is, the polarization states of the reference light LR and the signal light LS are matched, so that the polarization state can be optimized.

Thus, according to the fundus oculi observation device 1, the polarization adjustment between the reference light LR and the signal light LS in the OCT measurement can be suitably performed.

Also, the fundus oculi observation device 1 has a first blocking mechanism (galvano scanner 42) that blocks the signal light path. The detection unit detects the polarization state of the reference light LR in a state where the signal light path is blocked. The galvano scanner 42 is a scanning unit that scans the signal light LS. With such a configuration, it is possible to detect the polarization state of the reference light LR in a fundus oculi observation device of the type that scans the object to be measured with the signal light LS without adding new hardware. Note that the detection of the polarization state of the reference light LR may be realized using a first blocking mechanism of another form, such as the shutter described above.

Also, the fundus oculi observation device 1 has a second blocking mechanism (light attenuator 105) that blocks the reference optical path. The adjustment unit adjusts the polarization state in a state where the reference optical path is blocked. With such a configuration, in the fundus oculi observation device of the type having the optical attenuator 105, it is possible to suitably adjust the polarization state of the reference light LR without adding new hardware. In addition, you may use the 2nd interruption | blocking mechanism which consists of other forms like a shutter.

(Modification 2)
In the embodiment and the first modification, the polarization state of the reference light is adjusted. However, the polarization state of the signal light may be adjusted. In the fundus oculi observation device configured as described above, the adjustment unit adjusts the polarization state of the signal light by performing the same processing as in the above embodiment based on the detection results of the polarization states of the signal light and the reference light. I do. The adjustment unit includes, for example, a control unit and a polarization adjuster provided in the signal optical path. The polarization adjuster is an example of a “mechanism for changing the polarization state”. The control unit determines a setting state of the polarization adjuster that maximizes the intensity of the interference light based on the detection result of the polarization state of the signal light and the reference light, and controls the polarization adjuster based on the determination result. As a result, the polarization state of the signal light is adjusted.

The forming unit forms a fundus image based on the detection result of the interference light obtained by superimposing the signal light and the reference light after the polarization state of the signal light is adjusted.

According to such a fundus oculi observation device, the polarization states of the signal light and the reference light are actually measured, and the intensity of the interference light is adjusted based on the measurement results (that is, the polarization states of the signal light and the reference light are matched) )It can be performed. Therefore, it is possible to match the polarization states of the reference light and the signal light at the present time.

Also, unlike the conventional technology that monitors the intensity of interference light that is affected by various factors other than the polarization state, it is configured to monitor the intensity of the signal light and the reference light accompanying the change in the polarization state. It is possible to optimize the polarization state.

Such a fundus oculi observation device can suitably adjust the polarization between the reference light and the signal light in OCT measurement.

Also, this fundus oculi observation device has a first blocking mechanism (for example, an optical attenuator, such as a shutter) that blocks the reference optical path. The detection unit detects the polarization state of the signal light in a state where the reference optical path is blocked. By using the optical attenuator as the first blocking mechanism, it is possible to realize the detection of the polarization state of the signal light in the fundus observation device of the type having the optical attenuator without adding new hardware. is there.

Also, this fundus oculi observation device has a second blocking mechanism (for example, a galvano scanner, which may be a shutter or the like) that blocks the signal light path. The adjustment unit adjusts the polarization state in a state where the signal optical path is blocked. With such a configuration, in the fundus oculi observation device of the type having a scanning unit (galvano scanner), it is possible to suitably adjust the polarization state of the signal light without adding new hardware.

Instead of adjusting the polarization state of one of the signal light and the reference light as described above, it is possible to adjust both polarization states. That is, the adjustment of the polarization state only needs to be performed so that the polarization states of the signal light and the reference light coincide with each other. Therefore, this may be realized while changing the polarization states of both lights. The adjustment process in this case is the same as that of the above modification in the above embodiment.

(Modification 3)
In Modified Examples 3 to 5, an example in which the polarization state is detected and adjusted in response to a predetermined trigger will be described.

The fundus oculi observation device according to this modification has, for example, a determination unit in addition to the configuration of the above embodiment. The determination unit acquires information related to the image quality of the image formed by the forming unit and determines the image quality. In the above embodiment (FIG. 3), the determination unit is provided in the control unit 210 or the image processing unit 230. “Information relating to image quality” means arbitrary information that affects image quality, and is appropriately determined according to the image quality determination method.

The image quality determination process is performed using any known technique. As an example, there is a method of obtaining the image quality by analyzing the image itself formed by the forming unit. It is also possible to detect signal light and / or interference light, acquire the intensity of the detected signal as “information on image quality”, and perform threshold processing on the signal intensity to determine the image quality. . Note that the image quality determination processing is not limited to these.

The detection unit and adjustment unit according to this modification operate based on the image quality determination result. In particular, the detection unit and the adjustment unit are configured to operate only when a determination result that the image quality is bad is obtained.

According to such a modification, it is possible to execute this at a timing that requires adjustment of the polarization state.

(Modification 4)
In the above embodiment, the polarization state is detected and adjusted after completion of alignment and focusing. However, the polarization state may be detected and / or adjusted in parallel with the alignment. This timing control is performed by the control unit 210. According to this modification, the inspection time can be shortened.

The “alignment unit” includes the alignment optical system 50. When alignment is performed automatically, the alignment unit includes the alignment optical system 50 and the control unit 210. Moreover, when performing alignment manually, the alignment part is comprised including the alignment optical system 50, the control part 210, and the user interface 240. FIG.

(Modification 5)
In the above embodiment, the detection unit and the adjustment unit are configured to operate in response to a predetermined operation (input of an instruction for operating the detection unit and the adjustment unit) using the operation unit 240B. It is also possible. That is, it can be configured to detect and adjust the polarization state in response to a user instruction. According to this modification, the user can adjust the polarization state at a desired timing.

(Other variations)
In the above embodiment, the optical path length difference between the optical path of the signal light LS and the optical path of the reference light LR is changed by changing the position of the optical path length changing unit 41, but this optical path length difference is changed. The method is not limited to this. For example, it is possible to change the optical path length difference by disposing a reflection mirror (reference mirror) in the optical path of the reference light and moving the reference mirror in the traveling direction of the reference light to change the optical path length of the reference light. Is possible. Further, the optical path length difference may be changed by moving the fundus camera unit 2 or the OCT unit 100 with respect to the eye E to change the optical path length of the signal light LS. In particular, when the measured object is not a living body part, the optical path length difference can be changed by moving the measured object in the depth direction (z direction).

The computer program for realizing the above embodiment can be stored in any recording medium readable by the computer. As this recording medium, for example, a semiconductor memory, an optical disk, a magneto-optical disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), a magnetic storage medium (hard disk / floppy (registered trademark) disk / ZIP, etc.), etc. Can be used.

It is also possible to send and receive this program through a network such as the Internet or a LAN.

DESCRIPTION OF SYMBOLS 1 Fundus observation apparatus 2 Fundus camera unit 10 Illumination optical system 30 Shooting optical system 31 Focusing lens 31A Focusing drive part 41 Optical path length change part 42 Galvano scanner 50 Alignment optical system 60 Focus optical system 100 OCT unit 101 Light source unit 105 Light attenuation Device 106 polarization adjustment device 115 CCD image sensor 122 polarizing plate 122A actuator 123 detection element 200 arithmetic control unit 210 control unit 211 main control unit 212 storage unit 220 image forming unit 230 image processing unit 240A display unit 240B operation unit E eye Ef to be examined Fundus LS Signal light LR Reference light LC Interference light

Claims

A first optical system that irradiates the fundus of the subject's eye with illumination light and guides fundus reflection light of the illumination light to an imaging device;
A second optical system that divides light from a light source into signal light and reference light, causes the signal light and the reference light that have passed through the fundus of the eye to be inspected to generate interference light, and detects the interference light Have a system and
A fundus oculi observation device that acquires a fundus image representing a surface form of the fundus oculi based on a detection result by the imaging device, and acquires a tomographic image of the fundus oculi based on a detection result by the second optical system,
The first optical system includes:
A perforated mirror having a hole,
Including an objective lens and
Irradiating the fundus through the objective lens with the illumination light reflected by the aperture mirror, and guiding the fundus reflected light through the objective lens to the imaging device through the hole,
The second optical system includes:
A dichroic mirror that is disposed between the aperture mirror and the objective lens and branches the optical path of the signal light from the optical path of the first optical system;
Irradiating the fundus with the signal light via the dichroic mirror through the objective lens, and causing the signal light via the fundus and the objective lens to interfere with the reference light through the dichroic mirror. A fundus observation device.
The dichroic mirror branches the optical path of the signal light from the optical path of the first optical system by substantially transmitting the illumination light and the fundus reflected light and substantially reflecting the signal light. The fundus oculi observation device according to claim 1, wherein:
3. The fundus oculi observation device according to claim 2, wherein the dichroic mirror is configured to transmit 95% or more of light having a wavelength of 400 nm to 770 nm and reflect 95% or more of light having a wavelength of 790 nm or more. .
The fundus oculi observation device according to any one of claims 1 to 3, wherein a focusing lens is provided in each of the first optical system and the second optical system.