JP2019154999A - Light source control device, ophthalmologic apparatus, and light source control method - Google Patents

Abstract

To provide a light source control device, an ophthalmologic apparatus, and a light source control method which can control the quantity of light to be projected onto an object to be measured without causing upsizing of the optical system and decrease of the light quantity.SOLUTION: The light source control device includes: a light bifurcation unit for bifurcating output light from a wavelength sweeping light source into first output light and second output light; a combined-light creation unit for bifurcating the first output light into first bifurcated light and second bifurcated light, and combines the first bifurcated light and the second bifurcated light, which are routed through their respective optical paths with optical path lengths different from each other, to create combined light; a light receiving unit for receiving the combined light; and a light source control unit for controlling the light quantity of the output light on the basis of a result of light receiving by the light receiving unit.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a light source control device, an ophthalmologic device, and a light source control method.

  In recent years, OCT that forms an image representing the surface form or 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 (Computed Tomography), 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 or cornea has been put into practical use. An apparatus (OCT apparatus) using such an OCT technique can be applied to observation of various parts of an eye to be examined and can acquire high-definition images, and thus is applied to diagnosis of various ophthalmic diseases. .

  For example, Patent Document 1 discloses a swept source type OCT apparatus. This OCT apparatus scans (wavelength sweeps) the wavelength of the light irradiated to the object to be measured, detects the interference light obtained by superimposing the reflected light of each wavelength and the reference light, and calculates the spectral intensity distribution. The form of the object to be measured is imaged by acquiring and subjecting it to Fourier transform.

  In such an OCT apparatus, from the viewpoint of safety or the like, it is required to monitor the amount of light irradiated to the object to be measured and to control to irradiate the object to be measured with light of a predetermined amount or less. ing. For example, it is conceivable to provide a power monitor inside the OCT optical system in order to monitor the amount of light irradiated to the object to be measured. Patent Document 2 discloses a configuration in which light from a light source is branched and the power of the branched light is monitored.

JP 2007-24677 A JP2015-129741A

  However, in the conventional method, since it is necessary to branch the light in order to monitor the light amount, a loss of the light amount causes a decrease in measurement accuracy and image quality. In addition, it is necessary to add an optical element for branching light, so that the configuration of the optical system becomes complicated, and the size and cost of the apparatus increase.

  The present invention has been made in view of such circumstances, and an object of the present invention is to control the amount of light irradiated to the object to be measured without causing an increase in the size of the optical system or a decrease in the amount of light. A light source control device, an ophthalmologic device, and a light source control method are provided.

  A first aspect of some embodiments is a light source control device for controlling a wavelength swept light source, wherein the output light from the wavelength swept light source is branched into a first output light and a second output light. And the first branched light and the second branched light, and the first branched light and the second branched light that have passed through optical paths having different optical path lengths are combined into a combined light. A combined light generation unit that generates the light, a light receiving unit that receives the combined light, and a light source control unit that controls the amount of the output light based on a light reception result by the light receiving unit.

  A second aspect of some embodiments includes, in the first aspect, a detection unit that compares an integration result obtained by integrating the light reception result of the light receiving unit with a threshold value, and the light source control unit includes the light source control unit, The light quantity is controlled based on the comparison result obtained by the detection unit.

  In a third aspect of some embodiments, in the first aspect or the second aspect, the light source control unit performs output stop control or light amount of the wavelength swept light source when the light amount of the output light is equal to or greater than a predetermined threshold value. Decrease control is performed.

  In a fourth aspect of some embodiments, in the first aspect, the light source control unit controls the light amount based on a temporal change in a light reception result by the light receiving unit.

  A fifth aspect of some embodiments includes, in the fourth aspect, a storage unit that stores in advance reference change information of a light reception result by the light receiving unit, and the light source control unit stores the reference stored in the storage unit The light quantity is controlled based on the correlation between the change information and the temporal change in the light reception result by the light receiving unit.

  In a sixth aspect of some embodiments, in the fifth aspect, the light source control unit performs the wavelength sweep when a correlation value between the reference change information and a temporal change in a light reception result by the light receiving unit is a threshold value or less. Perform light source output stop control.

  In a seventh aspect of some embodiments, in any one of the fourth to sixth aspects, the light source control unit performs output stop control of the wavelength swept light source when the light reception result does not change over a predetermined period. Do.

  In an eighth aspect of some embodiments, in any one of the first to seventh aspects, the combined light generation unit includes a Mach-Zehnder interferometer, and combines the light output from the Mach-Zehnder interferometer. Output as light.

  In a ninth aspect of some embodiments, in any one of the first to eighth aspects, the light receiving unit includes a photodetector that receives the combined light.

  In a tenth aspect of some embodiments, in any one of the first to eighth aspects, the light receiving unit receives a first combined light obtained by branching the combined light. And a balance detector including a second light receiving element that receives the second combined light obtained by branching the combined light, the light receiving result of the first light receiving element or the light receiving result of the second light receiving element Is output.

  In an eleventh aspect of some embodiments, the light source control device according to any one of the first aspect to the tenth aspect, the second output light is divided into reference light and measurement light, and the measurement light is received. An interference optical system that irradiates the eye and detects the interference light between the return light of the measurement light from the eye to be examined and the reference light, and samples the detection result of the interference light based on the light reception result by the light receiving unit And an image forming unit that forms an image of the eye to be examined based on the detected detection result of the interference light.

  A twelfth aspect of some embodiments is a light source control method for controlling a wavelength swept light source, the light branching branching output light from the wavelength swept light source into first output light and second output light. A step of splitting the first output light into a first branched light and a second branched light, and combining the first branched light and the second branched light via optical paths having different optical path lengths from each other. And a light receiving step for receiving the combined light, and a light source control step for controlling the light quantity of the output light based on the light reception result in the light receiving step.

  In a thirteenth aspect of some embodiments, in the twelfth aspect, the light source control step controls the light amount based on a comparison result between an integration result obtained by integrating the light reception result and a threshold value.

  In a fourteenth aspect of some embodiments, in the twelfth aspect or the thirteenth aspect, the light source control step includes the output stop control or the light amount of the wavelength sweep light source when the light amount of the output light is equal to or greater than a predetermined threshold value. Decrease control is performed.

  In a fifteenth aspect of some embodiments, in the twelfth aspect, the light source control step controls the light amount based on a temporal change in the light reception result.

  In a sixteenth aspect of some embodiments, in the fifteenth aspect, the light source control step controls the light amount based on a correlation between reference change information stored in advance and a temporal change in the light reception result.

  In a seventeenth aspect of some embodiments, in the sixteenth aspect, in the sixteenth aspect, when the correlation value between the reference change information and the temporal change in the light reception result is a threshold value or less, the output of the wavelength swept light source Perform stop control.

  In an eighteenth aspect of some embodiments, in any one of the twelfth to seventeenth aspects, the light source control step performs output stop control of the wavelength swept light source when the light reception result does not change for a predetermined period. Do.

  According to the present invention, there are provided a light source control device, an ophthalmologic apparatus, and a light source control method capable of controlling the amount of light emitted to an object to be measured without causing an increase in the size of an optical system or a decrease in the amount of light. Is possible.

It is the schematic showing the example of a structure of the optical system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of a structure of the optical system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of a structure of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of a structure of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of a structure of the processing system of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is the schematic for demonstrating operation | movement of the ophthalmologic apparatus which concerns on embodiment. It is the schematic showing the example of a structure of the ophthalmologic apparatus which concerns on the modification of embodiment. It is the schematic showing the example of a structure of the ophthalmologic apparatus which concerns on the modification of embodiment. It is the schematic showing the example of a structure of the ophthalmologic apparatus which concerns on the modification of embodiment. It is the schematic showing the example of operation | movement of the ophthalmologic apparatus which concerns on the modification of embodiment.

  Examples of a light source control apparatus, an ophthalmologic apparatus, and a light source control method according to some embodiments of the present invention will be described in detail with reference to the drawings. In addition, the matter described in the literature referred by this specification, and arbitrary well-known techniques can be used for embodiment.

  The light source control device and the light source control method according to the embodiment are applied to an optical coherence tomography capable of executing swept source OCT on an object to be measured. The optical coherence tomography according to some embodiments is included in an ophthalmologic apparatus capable of performing swept source OCT on an eye to be examined as an object to be measured. An ophthalmic device according to some embodiments includes a light source control device. An ophthalmologic apparatus according to some embodiments includes a wavelength swept light source and a light source control device that controls an output light amount of the wavelength swept light source.

  The ophthalmologic apparatus according to some embodiments includes any one or more of an ophthalmologic imaging apparatus, an ophthalmologic measurement apparatus, and an ophthalmic treatment apparatus. The ophthalmologic photographing apparatus included in the ophthalmic apparatus is, for example, one or more of a fundus camera, a scanning laser ophthalmoscope, a slit lamp ophthalmoscope, a surgical microscope, and the like. The ophthalmologic measurement apparatus included in the ophthalmologic apparatus is, for example, any one or more of an eye refraction examination apparatus, a tonometer, a specular microscope, a wavefront analyzer, a perimeter, a microperimeter, and the like. The ophthalmic treatment apparatus included in the ophthalmologic apparatus is, for example, any one or more of a laser treatment apparatus, a surgical apparatus, a surgical microscope, and the like.

  Hereinafter, the case where the ophthalmologic apparatus according to the embodiment includes an optical coherence tomography and a fundus camera will be described.

<Configuration>
〔Optical system〕
As shown in FIG. 1, the ophthalmologic apparatus 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic control unit 200. The fundus camera unit 2 is provided with an optical system and mechanism for acquiring a front image of the eye E. The OCT unit 100 is provided with a part of an optical system and a mechanism for performing OCT. Another part of the optical system and mechanism for performing OCT is provided in the fundus camera unit 2. The arithmetic control unit 200 includes one or more processors that execute various types of arithmetic operations and controls. In addition to these, optional elements such as a member for supporting the subject's face (chin rest, forehead rest, etc.) and a lens unit for switching the OCT target site (for example, anterior segment OCT attachment) A unit may be provided in the ophthalmic apparatus 1.

  In this specification, the “processor” is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (eg, SPLD (Simple ProLigL). It means a circuit such as Programmable Logic Device (FPGA) or Field Programmable Gate Array (FPGA). For example, the processor implements the functions according to the embodiment by reading and executing a program stored in a storage circuit or a storage device.

[Fundus camera unit 2]
The fundus camera unit 2 is provided with an optical system for photographing the fundus oculi Ef of the eye E to be examined. The acquired image of the fundus oculi Ef (referred to as a fundus oculi image, a fundus oculi photo or the like) is a front image such as an observation image or a captured image. The observation image is obtained by moving image shooting using near infrared light. The photographed image is a still image using flash light. Furthermore, the fundus camera unit 2 can capture a front image (anterior segment image) by photographing the anterior segment Ea of the eye E.

  The fundus camera unit 2 includes an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the eye E with illumination light. The imaging optical system 30 detects the return light of the illumination light from the eye E. The measurement light from the OCT unit 100 is guided to the eye E through the optical path in the fundus camera unit 2, and the return light is guided to the OCT unit 100 through the same optical path.

  The light (observation illumination light) output from the observation light source 11 of the illumination optical system 10 is reflected by the reflection mirror 12 having a curved reflecting surface, passes through the condensing lens 13 and passes through the visible cut filter 14. Near infrared light. Further, the observation illumination light is reflected by the mirror 16 and passes through the relay lenses 17 and 18, the diaphragm 19 and the relay lens 20. The observation illumination light is reflected by the peripheral part of the perforated mirror 21 (area around the perforated part), passes through the dichroic mirror 46, and is refracted by the objective lens 22 to be examined eye E (fundus Ef or anterior eye). Illuminate part Ea). The return light of the observation illumination light from the eye E 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, and passes through the dichroic mirror 55. . The return light transmitted through the dichroic mirror 55 is reflected by the mirror 32 via the photographing focusing lens 31. Further, the return light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and forms an image on the light receiving surface of the image sensor 35 by the condenser lens. The image sensor 35 detects return light at a predetermined frame rate. Note that the focus of the photographing optical system 30 is adjusted to match the fundus oculi Ef or the anterior eye segment Ea.

An LCD (Liquid Crystal Display) 39 displays a fixation target and an eyesight measurement target. A part of the light beam output from the LCD 39 is reflected by the half mirror 33 </ b> A, reflected by the mirror 32, passes through the hole of the perforated mirror 21 through the photographing focusing lens 31 and the dichroic mirror 55. The light beam that has passed through the aperture of the aperture mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected onto the fundus oculi Ef.

  By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the eye E can be changed. Examples of fixation positions include a fixation position for acquiring an image centered on the macula, a fixation position for acquiring an image centered on the optic disc, and the fundus center between the macula and the optic disc There is a fixation position for acquiring an image centered on the eye, and a fixation position for acquiring an image of a part (a fundus peripheral portion) far away from the macula. The ophthalmologic apparatus 1 according to some embodiments includes a GUI (Graphical User Interface) for designating at least one of such fixation positions. The ophthalmologic apparatus 1 according to some embodiments includes a GUI or the like for manually moving a fixation position (a display position of a fixation target).

  The configuration for presenting the movable fixation target to the eye E is not limited to a display device such as an LCD. For example, a movable fixation target can be generated by selectively lighting a plurality of light sources in a light source array (light emitting diode (LED) array or the like). In addition, a movable fixation target can be generated by one or more movable light sources.

  The alignment optical system 50 generates an alignment index used for alignment of the optical system with respect to the eye E. The alignment light output from the LED 51 passes through the apertures 52 and 53 and the relay lens 54, is reflected by the dichroic mirror 55, and passes through the hole of the perforated mirror 21. The light that has passed through the hole of the perforated mirror 21 passes through the dichroic mirror 46 and is projected onto the eye E by the objective lens 22. The corneal reflection light of the alignment light is guided to the image sensor 35 through the same path as the return light of the observation illumination light. Manual alignment and auto-alignment can be executed based on the received light image (alignment index image).

  The focus optical system 60 generates a split index used for focus adjustment with respect to the eye E. The focus optical system 60 is moved along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path (imaging optical path) of the imaging optical system 30. The reflection bar 67 can be inserted into and removed from the illumination optical path. When performing the focus adjustment, the reflecting surface of the reflecting bar 67 is inclinedly arranged in the illumination optical path. The focus light output from the LED 61 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, is reflected by the mirror 65, and is reflected by the condenser lens 66 as a reflecting rod 67. The light is once imaged and reflected on the reflection surface. 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 reflected light of the focus light is guided to the image sensor 35 through the same path as the cornea reflected light of the alignment light. Manual focus and autofocus can be executed based on the received light image (split index image).

  The dichroic mirror 46 combines the fundus imaging optical path and the OCT optical path. The dichroic mirror 46 reflects light in a wavelength band used for OCT and transmits light for fundus photographing. In the OCT optical path (measurement light optical path), the collimator lens unit 40, the optical path length changing unit 41, the optical scanner 42, the OCT focusing lens 43, the mirror 44, in order from the OCT unit 100 side to the dichroic mirror 46 side. In addition, a relay lens 45 is provided.

  The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1 and changes the length of the OCT optical path. This change in optical path length is used for optical path length correction according to the axial length, adjustment of the interference state, and the like. The optical path length changing unit 41 includes a corner cube and a mechanism for moving the corner cube.

  The optical scanner 42 is disposed at a position optically conjugate with the pupil of the eye E. The optical scanner 42 deflects the measurement light passing through the OCT optical path. The optical scanner 42 is, for example, a galvano scanner capable of two-dimensional scanning.

  The OCT focusing lens 43 is moved along the optical path of the measurement light LS in order to adjust the focus of the OCT optical system. The movement of the photographing focusing lens 31, the movement of the focus optical system 60, and the movement of the OCT focusing lens 43 can be controlled in a coordinated manner.

[OCT unit 100]
As illustrated in FIG. 2, the OCT unit 100 is provided with an optical system for executing the swept source OCT. This optical system includes an interference optical system. This interference optical system has a function of dividing light from a wavelength swept light source (wavelength variable light source) into measurement light and reference light, and return light of measurement light from the eye E and reference light via a reference light path. A function of generating interference light by superimposing and a function of detecting this interference light are provided. The detection result (detection signal) of the interference light obtained by the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic control unit 200.

  The light source unit 101 includes, for example, a wavelength swept light source and a light source control circuit that controls the wavelength swept light source. The light L0 output from the light source unit 101 is guided to the polarization controller 103 by the optical fiber 102 and its polarization state is adjusted. The light L0 whose polarization state has been adjusted is guided to the fiber coupler 105 by the optical fiber 104 and split into the measurement light LS and the reference light LR.

  The reference light LR is guided to the collimator 111 by the optical fiber 110 and converted into a parallel light beam, and is guided to the corner cube 114 via the optical path length correction member 112 and the dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR and the optical path length of the measurement light LS. The dispersion compensation member 113 acts to match the dispersion characteristics between the reference light LR and the measurement light LS. The corner cube 114 is movable in the incident direction of the reference light LR, and thereby the optical path length of the reference light LR is changed.

  The reference light LR that has passed through the corner cube 114 passes through the dispersion compensation member 113 and the optical path length correction member 112, is converted from a parallel light beam to a focused light beam by the collimator 116, and enters the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided to the polarization controller 118 and its polarization state is adjusted. The reference light LR is guided to the attenuator 120 by the optical fiber 119 and the amount of light is adjusted, and is guided to the fiber coupler 122 by the optical fiber 121. It is burned.

  On the other hand, the measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and converted into a parallel light beam by the collimator lens unit 40, and the optical path length changing unit 41, the optical scanner 42, the OCT focusing lens 43, and the mirror 44. And via the relay lens 45. The measurement light LS passing through the relay lens 45 is reflected by the dichroic mirror 46, is refracted by the objective lens 22, and enters the eye E. The measurement light LS is scattered and reflected at various depth positions of the eye E. The return light of the measurement light LS from the eye E travels in the reverse direction on the same path as the forward path, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

  The fiber coupler 122 combines (interferes) the measurement light LS incident through the optical fiber 128 and the reference light LR incident through the optical fiber 121 to generate interference light. The fiber coupler 122 generates a pair of interference light LC by branching the interference light at a predetermined branching ratio (for example, 1: 1). The pair of interference lights LC are guided to the detector 125 through optical fibers 123 and 124, respectively.

  The detector 125 is a balance detector. The balance detector includes, for example, a balanced photodiode. The balanced photodiode includes a pair of photodetectors that respectively detect the pair of interference lights LC, and outputs a difference between a pair of detection results obtained by these photodetectors. The detector 125 sends this output (detection signal) to a DAQ (Data Acquisition System) 130.

  The clock 130 is supplied from the light source unit 101 to the DAQ 130. The clock KC is generated in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the wavelength swept light source in the light source unit 101. The DAQ 130 samples the detection signal input from the detector 125 based on the clock KC. The DAQ 130 sends the sampling result of the detection signal from the detector 125 to the arithmetic control unit 200.

  The light source unit 101 monitors a signal for generating the clock KC or the clock KC, and the output light amount of the wavelength swept light source is controlled based on the monitoring result. Accordingly, it is not necessary to branch the light in order to monitor the light amount of the measurement light LS irradiated to the eye E, and it is possible to suppress a decrease in measurement accuracy and image quality due to the loss of the light amount of the measurement light LS. Further, since the configuration of the swept source OCT is diverted, it is not necessary to add an optical element for branching light, and the configuration of the optical system can be simplified, and the apparatus can be reduced in size and cost. .

  FIG. 3 shows a configuration example of the light source unit 101 of FIG. In FIG. 3, the same parts as those in FIG.

  The light source unit 101 includes a wavelength swept light source 300 and a light source control circuit 101A that controls an output light amount of the wavelength swept light source 300. 3, the light source control circuit 101A includes a fiber coupler 302, an interference light generation unit 310, a lens 316, a light receiving unit 320, a detection circuit 330, and a light source control unit 340. In some embodiments, the wavelength swept light source 300 is provided outside the ophthalmic apparatus 1, and the light source unit 101 includes a light source control circuit 101A.

  The wavelength swept light source 300 includes, for example, a near-infrared wavelength tunable laser that changes the wavelength of emitted light at high speed. The output light of the wavelength swept light source 300 is guided to the fiber coupler 302 by the optical fiber 301. The fiber coupler 302 branches the output light of the wavelength swept light source 300 into a first output light and a second output light. The first output light is guided to the interference light generation unit 310 via the optical fiber 303. The second output light is guided to the optical fiber 102 and is output from the light source unit 101 as light L0.

  The interference light generation unit 310 includes a Mach-Zehnder interferometer. That is, the interference light generation unit 310 branches the first output light guided by the optical fiber 303 into the first branched light and the second branched light by the fiber coupler 311. The first branched light is guided to the fiber coupler 314 via the optical fiber 312. The second branched light is guided to the fiber coupler 314 via the optical fiber 313. The two optical paths formed by the optical fibers 312 and 313 have different optical path lengths by a known method. In some embodiments, the difference between the two optical path lengths can be adjusted in response to an instruction from a control unit described later. The optical path length difference may be adjusted based on the sampling result of the detection signal from the detector 125. In some embodiments, the polarization state of at least one of the first branched light and the second branched light is adjusted by a polarization controller. The first branched light that has passed through the optical fiber 312 and the second branched light that has passed through the optical fiber 313 are combined by the fiber coupler 314 and output interference light (combined light).

  The interference light generated by the interference light generation unit 310 is guided to the lens 316 by the optical fiber 315 and received by the light receiving unit 320. The light receiving unit 320 includes a photodetector (photodiode). The photodetector outputs an electrical signal (current value) corresponding to the amount of interference light emitted from the lens 316 as a light reception result (PD signal). In some embodiments, the clock KC is generated based on the light reception result (PD signal) obtained by the light receiving unit 320.

  The detection circuit 330 smoothes (integrates) the light reception result (PD signal) obtained by the light receiving unit 320, and the detection circuit 330 calculates the integration result of the light reception result obtained by the light receiving unit 320 and a predetermined first threshold value. Compare When the integration result of the light reception result is equal to or greater than the first threshold, it can be detected that the light amount of the output light from the wavelength swept light source 300 is equal to or greater than the predetermined light amount. The detection circuit 330 outputs the detection result to the light source control unit 340.

  FIG. 4 shows a configuration example of the detection circuit 330 in FIG. In FIG. 4, the same parts as those in FIG.

  The detection circuit 330 includes an integration circuit including a resistance element 331, a capacitor 332, and an operational amplifier 333, and a comparison circuit 334. One end of a resistance element 331 is electrically connected to the inverting input terminal of the operational amplifier 333. The other end of the resistance element 331 is supplied with a PD signal that is a light reception result of the light receiving unit 320. A capacitor 332 is electrically connected between the inverting input terminal and the output terminal of the operational amplifier 333. A ground power supply is supplied to the non-inverting input terminal of the operational amplifier 333. A comparison circuit 334 is connected to the output terminal of the operational amplifier 333.

  Since the integration circuit having such a configuration is known, a detailed description thereof will be omitted. Since the inverting input terminal of the operational amplifier 333 is virtually grounded, the PD signal (current value) flowing through the resistance element 331 becomes equal to the current flowing through the capacitor 332. A voltage obtained by integrating the input voltage of the non-inverting input terminal corresponding to the resistance value of the resistance element 331 and the capacitance value of the capacitor 332 is generated at the output terminal of the operational amplifier 333. The comparison circuit 334 is supplied with a voltage TH corresponding to the first threshold value. For example, the comparison circuit 334 is a known circuit that outputs a voltage corresponding to the comparison result between the output voltage of the operational amplifier 333 and the voltage TH.

  The detection circuit 330 according to some embodiments detects whether the output of the wavelength swept light source 300 has stopped based on the light reception result (PD signal) obtained by the light receiving unit 320 or the integration result thereof. The detection circuit 330 compares the integration result of the light reception result obtained by the light receiving unit 320 with a predetermined second threshold value. When the period in which the integration result of the light reception result is equal to or less than the second threshold is continued for a predetermined period or more, the stop of the output of the wavelength sweep light source 300 can be detected. The detection circuit 330 outputs the detection result to the light source control unit 340.

  The detection circuit 330 according to some embodiments detects whether the output of the wavelength swept light source 300 has changed based on the light reception result (PD signal) obtained by the light receiving unit 320 or the integration result thereof. The detection circuit 330 can detect that the output of the wavelength swept light source 300 does not change when the light reception result or the integration result obtained by the light receiving unit 320 does not change for a predetermined period or longer. The detection circuit 330 outputs the detection result to the light source control unit 340.

  The light source control unit 340 controls the wavelength swept light source 300 based on the detection result obtained by the detection circuit 330. That is, the light source control unit 340 can control the wavelength swept light source 300 based on the light reception result of the light receiving unit 320. The light source control unit 340 can control the turning on / off of the wavelength sweep light source 300, the amount of output light, the wavelength sweep range, the wavelength sweep speed, the sweep start wavelength, the sweep end wavelength, and the like.

  Based on the detection result obtained by the detection circuit 330, the light source control unit 340 performs output stop control or light amount reduction control of the wavelength sweep light source 300 when the light amount of the output light of the wavelength sweep light source 300 is equal to or greater than the first threshold. Do. The output stop control is control for stopping the output of light. As an example of output stop control, there is stop control of output of output light to the wavelength sweep light source 300. When the light source control unit 340 can control the drive unit that drives the shutter member so that the shutter member can be inserted into and removed from the optical path of the output light, the output of the wavelength swept light source 300 is an example of output stop control. There is control for inserting a shutter member into the optical path of light. The light amount reduction control is control for reducing the light amount of the output light. As an example of the light amount reduction control, there is a reduction control of the light amount of the output light with respect to the wavelength sweep light source 300. When the light source controller 340 controls the drive unit that drives the dimming member so that the dimming member can be inserted into and removed from the optical path of the output light, the wavelength swept light source 300 is an example of the light amount reduction control. There is a control to insert a dimming member into the optical path of the output light. The light source control unit 340 performs output stop control of the wavelength swept light source 300 when the light reception result of the light receiving unit 320 does not change over a predetermined period based on the detection result obtained by the detection circuit 330.

  In this example, the optical path length changing unit 41 for changing the length of the optical path (measurement optical path, measurement arm) of the measurement light LS and the length of the optical path (reference optical path, reference arm) of the reference light LR are changed. Both corner cubes 114 are provided. However, only one of the optical path length changing unit 41 and the corner cube 114 may be provided. It is also possible to change the difference between the measurement optical path length and the reference optical path length using optical members other than these.

[Control system]
FIG. 5 shows a configuration example of the control system of the ophthalmologic apparatus 1. In FIG. 5, some of the components included in the ophthalmologic apparatus 1 are omitted. The control unit 210, the image forming unit 220, and the data processing unit 230 are provided in the arithmetic control unit 200, for example.

<Control unit 210>
The control unit 210 executes various controls. The control unit 210 includes a main control unit 211 and a storage unit 212.

<Main control unit 211>
The main control unit 211 includes a processor and controls each unit of the ophthalmologic apparatus 1 (including each element shown in FIGS. 1 to 4). For example, the main control unit 211 controls the focusing drive units 31A and 43A, the image sensors 35 and 38, the LCD 39, the optical path length changing unit 41, and the optical scanner 42 of the fundus camera unit 2. Further, the main control unit 211 controls the moving mechanism 150. Further, the main control unit 211 controls the light source unit 101 (light source control circuit 101A), the reference drive unit 114A, the detector 125, the DAQ 130, and the like of the OCT unit 100.

  The focusing drive unit 31 </ b> A receives the control from the main control unit 211 and moves the shooting focusing lens 31 along the optical axis of the shooting optical system 30. The focusing drive unit 31A is provided with a holding member that holds the photographing focusing lens 31, an actuator that generates a driving force for moving the holding member, and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. Thereby, the focusing position of the imaging optical system 30 is changed when the focusing drive unit 31A under the control of the main control unit 211 moves the imaging focusing lens 31. Note that the focusing drive unit 31A may move the imaging focusing lens 31 along the optical axis of the imaging optical system 30 by manual or user operation on the operation unit 240B.

  Under the control of the main control unit 211, the focusing drive unit 43A moves the OCT focusing lens 43 along the optical axis of the interference optical system (the optical path of the measurement light) in the OCT unit 100. The focusing drive unit 43A includes a holding member that holds the OCT focusing lens 43, an actuator that generates a driving force for moving the holding member, and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is configured by, for example, a combination of gears, a rack and pinion, or the like. As a result, the focusing drive unit 43A under the control of the main control unit 211 moves the OCT focusing lens 43, thereby changing the focus position of the measurement light. Note that the focusing drive unit 43A may move the OCT focusing lens 43 along the optical axis of the interference optical system by manual or user operation on the operation unit 240B.

  The main controller 211 can control the exposure time (charge accumulation time), gain, frame rate, and the like of the image sensor 35. The main control unit 211 can control the exposure time, gain, frame rate, and the like of the image sensor 38.

  The main control unit 211 can perform display control of the fixation target and the visual acuity measurement target for the LCD 39. Thereby, it is possible to switch the target presented to the eye E and change the type of the target. In addition, by changing the display position of the target on the LCD 39, the target display position for the eye E can be changed.

  The main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling the optical path length changing unit 41. The main control unit 211 controls the optical path length changing unit 41 so that the target site of the eye E is depicted in a predetermined range within the frame of the OCT image. Specifically, the main control unit 211 controls the optical path length changing unit 41 so that the target site of the eye E is drawn at a predetermined z position (position in the depth direction) in the frame of the OCT image. Is possible.

  The main control unit 211 can change the projection position of the measurement light LS on the fundus oculi Ef or the anterior eye part of the eye E by controlling the optical scanner 42.

  The moving mechanism 150 moves, for example, at least the fundus camera unit 2 (optical system) in a three-dimensional manner. In a typical example, the moving mechanism 150 includes at least a mechanism for moving the fundus camera unit 2 in the x direction (left and right direction), a mechanism for moving in the y direction (up and down direction), and a z direction (depth direction). And a mechanism for moving in the front-rear direction). The mechanism for moving in the x direction includes, for example, an x stage that can move in the x direction and an x moving mechanism that moves the x stage. The mechanism for moving in the y direction includes, for example, a y stage that can move in the y direction and a y moving mechanism that moves the y stage. The mechanism for moving in the z direction includes, for example, a z stage movable in the z direction and a z moving mechanism for moving the z stage. Each moving mechanism includes an actuator such as a pulse motor and operates under the control of the main control unit 211.

  In the case of manual alignment, the user moves the optical system and the eye E relative to each other by operating a user interface 240 described later so that the displacement of the eye E to the optical system is canceled. For example, the main control unit 211 controls the moving mechanism 150 to output relative movement between the optical system and the eye E by outputting a control signal corresponding to the operation content on the user interface 240 to the moving mechanism 150.

  In the case of auto alignment, the main control unit 211 controls the movement mechanism 150 so that the displacement of the eye E with respect to the optical system is canceled, thereby moving the optical system and the eye E relative to each other. In some embodiments, the main controller 211 controls the control signal so that the optical axis of the optical system substantially coincides with the axis of the eye E and the distance of the optical system with respect to the eye E is a predetermined working distance. Is output to the moving mechanism 150 to control the moving mechanism 150 to relatively move the optical system and the eye E to be examined. Here, the working distance is a predetermined value called a working distance of the objective lens 22 and corresponds to a distance between the eye E and the optical system at the time of measurement using the optical system (at the time of photographing).

  Such control of the moving mechanism 150 is used in alignment and tracking. Tracking refers to moving the apparatus optical system in accordance with the movement of the eye E. When tracking is performed, alignment and focusing are performed in advance. Tracking maintains a suitable positional relationship in which alignment and focus are achieved by moving the apparatus optical system in real time according to the position and orientation of the eye E based on an image obtained by taking a moving image of the eye E. It is a function.

  The main control unit 211 can control switching of turning on and off the output light, changing the light amount of the output light, and the like by controlling the light source unit 101. The main controller 211 can control the wavelength swept light source 300 via the light source control circuit 101A.

  The main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling the reference driving unit 114A. The main control unit 211 controls the reference driving unit 114A so that the target site of the eye E is depicted in a predetermined range within the frame of the OCT image. Specifically, the main control unit 211 can control the reference driving unit 114A so that the target site of the eye E is depicted at a predetermined z position in the frame of the OCT image. The main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling at least one of the optical path length changing unit 41 and the reference driving unit 114A. It is.

  The main controller 211 can control the exposure time (charge accumulation time), frequency response, and the like of the detector 125. Further, the main control unit 211 can control the DAQ 130.

<Storage unit 212>
The storage unit 212 stores various data. The data stored in the storage unit 212 includes eye data such as OCT data acquired using the OCT unit 100, OCT images, fundus images, anterior eye images, eye information, and the like. The eye information includes subject information such as patient ID and name, left / right eye identification information, electronic medical record information, and the like.

<Image forming unit 220>
The image forming unit 220 includes a processor and forms an image based on an output from the DAQ 130 (a sampling result of the detection signal). For example, like the conventional swept source OCT, the image forming unit 220 performs signal processing on the spectrum distribution based on the sampling result for each A line to form a reflection intensity profile for each A line, and converts these A line profiles into images. And arrange them along the scan line. The signal processing includes noise removal (noise reduction), filter processing, FFT (Fast Fourier Transform), and the like.

<Data processing unit 230>
The data processing unit 230 includes a processor and performs image processing and analysis processing on the image formed by the image forming unit 220. For example, the data processing unit 230 executes correction processing such as image luminance correction and dispersion correction.

  The data processing unit 230 can form volume data (voxel data) of the eye E by performing known image processing such as interpolation processing for interpolating pixels between tomographic images. When displaying an image based on volume data, the data processing unit 230 performs a rendering process on the volume data to form a pseudo three-dimensional image when viewed from a specific viewing direction.

<User interface 240>
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 ophthalmologic apparatus 1 or outside. The display unit 240 </ b> A may include various display devices such as a touch panel provided on the housing of the fundus camera unit 2.

  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, can be used. In that case, the operation unit 240B includes the touch panel and a computer. 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 graphical user interface (GUI) displayed on the display unit 240A and the operation unit 240B.

  The fiber coupler 302 is an example of an “optical branching unit” according to the embodiment. The interference light generation unit 310 is an example of a “combined light generation unit” according to the embodiment. The detection circuit 330 is an example of a “detection unit” according to the embodiment. The light source control circuit 101A is an example of a “light source control device” according to the embodiment. The optical system included in the OCT unit 100 illustrated in FIG. 2 is an example of the “interference optical system” according to the embodiment.

<Operation>
An operation example of the ophthalmologic apparatus 1 will be described.

  6 and 7 show an operation example of the ophthalmologic apparatus 1 according to the embodiment. FIG. 6 shows a flowchart of an operation example of the ophthalmologic apparatus 1. FIG. 7 is a flowchart illustrating an operation example of the light source control circuit 101A.

(S1: Turn on the wavelength sweep light source)
First, the main control unit 211 turns on the wavelength sweep light source 300 by controlling the light source control unit 340. Thereby, the wavelength swept light source 300 starts emission of a predetermined amount of output light.

(S2: Alignment)
Subsequently, the main control unit 211 performs alignment. For example, the main control unit 211 controls the alignment optical system 50 so as to project the alignment light onto the eye E, and controls the focus optical system 60 so as to project the focus light onto the eye E. Further, the main control unit 211 performs auto alignment and auto focus in the same manner as in the past. Thereby, alignment and focusing with respect to the fundus oculi Ef are completed.

(S3: Acquire a tomographic image)
Next, the main control unit 211 controls the optical scanner 42 and the OCT unit 100 so that OCT measurement is started. When the OCT measurement is started, the OCT unit 100 sends the data collected in each scan to the image forming unit 220. The image forming unit 220 forms a plurality of B-scan images from the data collected in each scan and sends it to the control unit 210. The control unit 210 sends a plurality of B scan images corresponding to each scan to the data processing unit 230. For example, the data processing unit 230 forms a three-dimensional image from a plurality of B scan images corresponding to each scan.

(S4: Display a tomographic image)
The main control unit 211 displays the formed two-dimensional image or three-dimensional image in a predetermined display area of the display unit 240A.

(S5: Turn off the wavelength sweep light source)
The main control unit 211 turns off the wavelength sweep light source 300 by controlling the light source control unit 340. Thereby, the wavelength sweep light source 300 stops the output of the output light. This is the end of the operation of the ophthalmologic apparatus 1 (end).

  When the wavelength swept light source 300 is turned on as in step S1 of FIG. 6, the light source control circuit 101A executes the following operation.

(S11: PD signal is detected)
As shown in step S1 of FIG. 6, when the lighting of the wavelength swept light source 300 is instructed, the wavelength swept light source 300 starts emitting output light. As described above, the interference light generation unit 310 generates interference light based on part of the output light of the wavelength swept light source 300. The light receiving unit 320 receives the interference light generated by the interference light generation unit 310 and outputs the light reception result as a PD signal.

(S12: smoothing)
The detection circuit 330 smoothes the PD signal detected in step S11, and determines whether or not the light amount of the output light from the wavelength swept light source 300 is equal to or greater than a predetermined light amount based on a comparison result between the result and the first threshold value. To detect. The detection result of the detection circuit 330 is sent to the light source control unit 340.

(S13: below threshold?)
Based on the detection result in step S12, when the smoothing result of the PD signal is equal to or smaller than the first threshold (S13: Y), the operation of the light source control circuit 101A proceeds to step S11. That is, the light source control unit 340 does not execute control for changing the light amount with respect to the wavelength swept light source 300.

  Based on the detection result in step S12, when the smoothing result of the PD signal is not less than or equal to the first threshold value (S13: N), the operation of the light source control circuit 101A proceeds to step S14.

(S14: Wavelength sweep light source is forcibly turned off)
When the smoothing result of the PD signal is not less than or equal to the first threshold value in step S13 (S13: N), the light source control unit 340 performs output stop control on the wavelength sweep light source 300. Thereafter, the operation of the light source control circuit 101A proceeds to step S11 (return).

  FIG. 8 is an operation explanatory diagram of the light source control circuit 101A according to the embodiment. In FIG. 8, the vertical axis represents the output power of the wavelength swept light source 300, and the horizontal axis represents time.

  After the wavelength sweep light source 300 is turned on, steps S11 to S14 shown in FIG. 7 are repeated. When the amount of output light of the wavelength swept light source 300 increases and exceeds the output power threshold Pth corresponding to the first threshold TH, the light source control unit 340 performs output stop control on the wavelength swept light source 300. Thereby, as shown in FIG. 8, the emission of the output light from the wavelength swept light source 300 is stopped.

<First Modification>
In the above-described embodiment, the case where the light receiving unit 320 receives the interference light formed by the interference light generating unit 310 with the photodetector has been described, but the configuration of the embodiment is not limited thereto. For example, the interference light may be received by a balance detector. Hereinafter, the configuration of the ophthalmologic apparatus according to the first modified example of the embodiment will be described focusing on differences from the embodiment.

  The configuration of the ophthalmologic apparatus according to the first modification is different from the configuration of the ophthalmologic apparatus 1 according to the embodiment in that a light source control circuit 101B is provided instead of the light source control circuit 101A.

  FIG. 9 shows a configuration example of a light source control circuit 101B according to a first modification of the embodiment. In FIG. 9, the same parts as those in FIG.

  The light source control circuit 101B according to the first modified example is different from the light source control circuit 101A according to the embodiment in that the fiber coupler 314 branches the interference light at a predetermined branching ratio (1: 1) to generate a pair of interference lights. The point to be generated is that optical fibers 351 and 352, lenses 353 and 354, and a light receiving unit 360 are provided instead of the optical fiber 315, the lens 316, and the light receiving unit 320.

  The fiber coupler 314 branches the interference light generated by combining the first branched light that has passed through the optical fiber 312 and the second branched light that has passed through the optical fiber 313, for example, into 1: 1, Interference light (first combined light) and second interference light (second combined light) are output. The first interference light is guided to the lens 353 by the optical fiber 351 and received by the light receiving unit 360. The second interference light is guided to the lens 354 by the optical fiber 352 and received by the light receiving unit 360. The light receiving unit 360 includes a balance detector. The balance detector outputs an electric signal (current value) corresponding to a light amount difference between the first interference light emitted from the lens 353 and the second interference light emitted from the lens 354 as a light reception result (PDB signal). In some embodiments, the clock KC is generated based on the light reception result obtained by the light receiving unit 360. The balance detector outputs an electric signal (current value) corresponding to the amount of the second interference light emitted from the collimator 354 as a light reception result (PD signal). The balance detector may output an electric signal (current value) corresponding to the amount of the first interference light emitted from the lens 53 as a light reception result (PD signal).

  FIG. 10 shows a configuration example of the light receiving unit 360 of FIG.

  The light receiving unit 360 includes a first photodetector 361 that receives the first branched light and a second photodetector 362 that receives the second branched light. The first photodetector 361 and the second photodetector 362 have substantially the same photoelectric conversion characteristics. Each of the first photodetector 361 and the second photodetector 362 includes a photodiode. That is, the light receiving unit 360 includes a balanced photodiode. In this case, the anode terminal of the photodiode of the first photodetector 361 is electrically connected to the cathode terminal of the photodiode of the second photodetector 362. The light receiving unit 360 cancels the common mode noise of the first branched light and the second branched light, and outputs an electrical signal (PDB signal) corresponding to a slight light amount difference.

  The cathode terminal of the photodiode of the first photodetector 361 is amplified by the amplifier 363. An electrical signal (current value) corresponding to the amount of the first interference light is output as a light reception result (PD1 signal). The current flowing through the connection node between the anode terminal of the photodiode of the first photodetector 361 and the cathode terminal of the photodiode of the second photodetector 362 is converted into a voltage signal by the current-voltage converter 364 and amplified by the amplifier 366. Is output as a light reception result (PDB signal). The PDB signal may be output as the clock KC. The anode terminal of the photodiode of the second photodetector 362 is amplified by the amplifier 366. An electrical signal (current value) corresponding to the amount of the second interference light is output as a light reception result (PD2 signal, PD signal). In FIG. 9, the PD2 signal is output as a PD signal.

  Since the operation of the ophthalmologic apparatus according to the first modified example having such a configuration is the same as that of the embodiment, detailed description thereof is omitted.

  The first interference light is an example of “first combined light” according to the embodiment. The second interference light is an example of “second combined light” according to the embodiment. The first photodetector 361 is an example of the “first light receiving element” according to the embodiment. The second photodetector 362 is an example of a “second light receiving element” according to the embodiment.

  According to the first modification, it is possible to detect a smaller amount of branched light, and thus it is possible to control the wavelength sweep light source 300 with higher accuracy than in the embodiment.

<Second Modification>
In the above embodiment or the second modification, the case where the wavelength swept light source 300 is controlled based on the light reception result of the light receiving unit or the integration result thereof has been described, but the configuration of the embodiment is not limited to this. For example, the wavelength swept light source 300 may be controlled based on a temporal change in the light reception result of the light receiving unit. Hereinafter, the configuration of the ophthalmologic apparatus according to the second modified example of the embodiment will be described focusing on differences from the embodiment.

  The configuration of the ophthalmologic apparatus according to the second modification is different from the configuration of the ophthalmologic apparatus 1 according to the embodiment in that a light source control circuit 101C is provided instead of the light source control circuit 101A.

  FIG. 11 shows a configuration example of a light source control circuit 101C according to a second modification of the embodiment. In FIG. 11, the same parts as those in FIG.

  The light source control circuit 101C according to the second modification is different from the light source control circuit 101A according to the embodiment in that an A / D converter 370 is provided instead of the detection circuit 330, and in place of the light source control unit 340. The light source control unit 380 is provided.

  The A / D converter 370 converts the light reception result (PD signal) obtained by the light receiving unit 320 into a digital value. The conversion result by the A / D converter 370 is sent to the light source control unit 380.

  The light source control unit 380 controls the amount of output light of the wavelength swept light source 300 based on the temporal change in the light reception result by the light receiving unit 320. Such a light source control unit 380 includes a storage unit 381. The storage unit 381 according to some embodiments is included in the storage unit 212 of FIG. The storage unit 381 sequentially stores the conversion results by the A / D converter 370 over a predetermined period.

  The storage unit 381 stores reference waveform information 381A in advance. The reference waveform information 381A according to some embodiments is information representing a reference temporal change in the light reception result of the light receiving unit 320. The reference waveform information 381A is stored at the time of designing or manufacturing and shipping. The light source control unit 380 according to some embodiments is based on the correlation between the reference waveform information 381A stored in the storage unit 381 and the temporal change in the light reception result by the light receiving unit 320. To control.

  The light source control unit 380 according to some embodiments calculates a correlation value between the reference waveform information 381A stored in the storage unit 381 and a temporal change in the light reception result by the light receiving unit 320, and the calculated correlation value is predetermined. When the value is equal to or less than the threshold value, output stop control of the wavelength sweep light source 300 is performed.

  The reference waveform information 381A is an example of “reference change information” according to the embodiment.

  In the second modification, when the wavelength swept light source 300 as in step S1 in FIG. 6 is turned on, the light source control circuit 101C performs the following operation.

  FIG. 12 shows an operation example of the light source control circuit 101C according to the second modification of the embodiment. FIG. 12 is a flowchart illustrating an operation example of the light source control circuit 101C according to the second modification.

(S21: PD signal detected)
As shown in step S1 of FIG. 6, when the lighting of the wavelength swept light source 300 is instructed, the wavelength swept light source 300 starts emitting output light. As described above, the interference light generation unit 310 generates interference light based on part of the output light of the wavelength swept light source 300. Similarly to step S11, the light receiving unit 320 receives the interference light generated by the interference light generation unit 310, and outputs the light reception result as a PD signal.

(S22: A / D conversion process)
The A / D converter 370 performs A / D conversion processing on the PD signal detected in step S <b> 11 and outputs a digital value of the PD signal to the light source control unit 380.

(S23: Save)
The light source control unit 380 sequentially stores the A / D conversion processing results in step S22 in the storage unit 381.

(S24: Has the predetermined period passed?)
The light source control unit 380 determines whether a predetermined period has elapsed with respect to the reference time. The reference time may be a lighting start time of the wavelength sweep light source 300 or a time when it is determined that the previous predetermined period has passed.

  When it is determined that the predetermined period has elapsed (step S24: Y), the operation of the light source control circuit 101C proceeds to step S25. When it is determined that the predetermined period has not elapsed (step S24: N), the operation of the light source control circuit 101C proceeds to step S21.

(S25: Comparison with reference waveform information)
When it is determined in step S24 that the predetermined period has elapsed (step S24: Y), the light source control unit 380 compares the reference waveform information 381A and the light reception result by the light receiving unit 320 sequentially stored in the storage unit 381. . The light source control unit 380 according to some embodiments calculates a correlation value between the reference waveform information 381A and the light reception result by the light receiving unit 320 sequentially stored in the storage unit 381, and calculates the calculated correlation value and the threshold value. Compare.

(S26: Forced stop?)
The light source control unit 380 determines whether or not the temporal change in the light reception result by the light receiving unit 320 greatly deviates from the reference waveform information 381A based on the comparison result in step S25. The light source control unit 380 determines to forcibly stop the output of the wavelength swept light source 300 when it is determined that the temporal change in the light reception result by the light receiving unit 320 greatly deviates from the reference waveform information 381A.

  The light source control unit 380 according to some embodiments determines whether the output light amount of the wavelength swept light source 300 has changed over a predetermined period based on the comparison result in step S25. The light source control unit 380 determines to forcibly stop the output of the wavelength swept light source 300 when it is determined that the output light amount has not changed.

  When it is determined that the output of the wavelength swept light source 300 is forcibly stopped (S26: Y), the operation of the light source control circuit 101C proceeds to step S27. When it is determined that the output of the wavelength swept light source 300 is not forcibly stopped (S26: N), the operation of the light source control circuit 101C proceeds to step S21 (return).

(S27: The wavelength sweep light source is forcibly turned off)
When it is determined in step S26 that the output of the wavelength sweep light source 300 is forcibly stopped (S26: Y), the light source control unit 380 performs output stop control on the wavelength sweep light source 300. Thereafter, the operation of the light source control circuit 101C proceeds to step S21 (return).

  In the second modification, the case where the light receiving unit 320 receives the interference light as illustrated in FIG. 11 has been described. However, the light receiving unit 360 according to the first modification can also receive the interference light.

  According to the second modification, the light amount of the output light from the wavelength swept light source 300 can be reduced based on the temporal change in the light amount of the output light from the wavelength swept light source 300. Therefore, as shown in FIG. 8, the output of the wavelength sweep light source 300 can be stopped as in the embodiment.

<Action and effect>
Operations and effects of the light source control device, the ophthalmologic apparatus, and the light source control method according to the embodiment will be described.

  The light source control devices (light source control circuits 101A to 101C) according to some embodiments are used to control the wavelength swept light source (300). The light source control device includes an optical branching unit (fiber coupler 302), a combined light generation unit (interference light generation unit 310), a light receiving unit (320, 360), and a light source control unit (340, 380). The optical branching unit branches the output light from the wavelength swept light source into the first output light and the second output light. The synthesized light generation unit divides the first output light into the first branched light and the second branched light, and synthesizes the first branched light and the second branched light that have passed through optical paths having different optical path lengths. (Interference light) is generated. The light receiving unit receives the combined light. The light source control unit controls the amount of output light based on the light reception result by the light receiving unit.

  According to such a configuration, since the OCT scan result acquired by the swept source OCT can be sampled based on the light reception result of the light receiving unit, the OCT optical system is used to monitor the light amount of the output light of the wavelength swept light source. There is no need to split light in the system. As a result, it is possible to suppress the loss of light amount and prevent the measurement accuracy and image quality from being lowered. Further, it is necessary to add an optical element for branching light, so that the configuration of the optical system can be simplified, and the size and cost of the apparatus can be reduced.

  The light source control device according to some embodiments includes a detection unit (detection circuit 330) that compares the integration result obtained by integrating the light reception result of the light reception unit with a threshold value, and the light source control unit includes the detection unit The amount of light is controlled based on the comparison result obtained by the above.

  According to such a configuration, since the wavelength swept light source is controlled based on the integration result of the light reception result, the wavelength swept light source can be controlled with high accuracy even when the light reception result changes slightly. become.

  In the light source control device according to some embodiments, the light source control unit performs output stop control or light amount reduction control of the wavelength sweep light source when the light amount of the output light is equal to or greater than a predetermined threshold.

  According to such a configuration, even when the amount of output light of the wavelength swept light source exceeds a threshold value, the amount of light irradiated to the object to be measured is reduced without causing an increase in the size of the optical system or a decrease in the amount of light. It becomes possible to control.

  In the light source control device according to some embodiments, the light source control unit controls the amount of light based on a temporal change in the light reception result by the light receiving unit.

  According to such a configuration, the wavelength swept light source can be controlled based on the temporal change in the light amount of the output light of the wavelength swept light source, so that the details can be obtained without causing an increase in the size of the optical system and a decrease in the light amount. Light quantity control becomes possible.

  The light source control device according to some embodiments includes a storage unit (381, storage unit 212) that stores in advance reference change information (reference waveform information 381A) of a light reception result by the light receiving unit, and the light source control unit includes a storage unit The amount of light is controlled based on the correlation between the reference change information stored in and the temporal change in the light reception result by the light receiving unit.

  According to such a configuration, the change in the output light of the wavelength swept light source can be analyzed based on the correlation with the reference change information defined in advance, so that the wavelength swept light source can be controlled with high accuracy.

  In the light source control device according to some embodiments, the light source control unit performs output stop control of the wavelength swept light source when the correlation value between the reference change information and the temporal change in the light reception result by the light receiving unit is equal to or less than a threshold value.

  According to such a configuration, since the correlation value between the reference change information and the temporal change in the light reception result by the light receiving unit is calculated, the wavelength sweep light source can be controlled with high accuracy by a simple process. .

  In the light source control device according to some embodiments, the light source control unit performs output stop control of the wavelength swept light source when the light reception result does not change over a predetermined period.

  According to such a configuration, even when the light amount of the output light from the wavelength swept light source does not change, more detailed light amount control can be performed without causing an increase in the size of the optical system or a decrease in the light amount.

  In the light source control apparatus according to some embodiments, the combined light generation unit includes a Mach-Zehnder interferometer, and outputs light output from the Mach-Zehnder interferometer as combined light.

  According to such a configuration, a known Mach-Zehnder interferometer can be used to control the amount of light irradiated to the object to be measured without causing an increase in the size of the optical system or a decrease in the amount of light. Become.

  In the light source control device according to some embodiments, the light receiving unit includes a photodetector that receives the combined light.

  According to such a configuration, it is possible to control the amount of light irradiated to the object to be measured with a simple configuration without causing an increase in the size of the optical system or a decrease in the amount of light.

  In the light source control device according to some embodiments, the light receiving unit receives the first combined light (first interference light) obtained by branching the combined light, and the first light receiving element (first photodetector 361). ) And a second light receiving element (second light detector 362) that receives the second combined light (second interference light) obtained by branching the combined light, The light reception result of the element or the light reception result of the second light receiving element is output.

  According to such a configuration, it is possible to detect a smaller amount of branched light, and thus it is possible to control the wavelength swept light source with high accuracy.

  An ophthalmologic apparatus (1) according to some embodiments includes the light source control device described above, an interference optical system (an optical system included in the OCT unit 100), and an image forming unit (220). The interference optical system divides the second output light (L0) into reference light (LR) and measurement light, irradiates the measurement light to the eye (E), and returns the measurement light from the test eye and the reference light. Interference light (LC) is detected. The image forming unit samples the detection result of the interference light based on the light reception result by the light receiving unit, and forms an image of the eye to be inspected based on the sampled detection result of the interference light.

  According to such a configuration, it is possible to provide an ophthalmologic apparatus capable of controlling the amount of light irradiated to the object to be measured without causing an increase in the size of the optical system or a decrease in the amount of light.

  The light source control method according to some embodiments includes a light branching step for branching output light from the wavelength swept light source (300) into first output light and second output light, and the first output light as first branched light. A combined light generation step of generating a combined light (interference light) by combining the first branched light and the second branched light that are branched into the first branched light and the second branched light and passed through optical paths having different optical path lengths. And a light source control step for controlling the amount of output light based on the light reception result in the light receiving step.

  According to such a configuration, since the OCT scan result acquired by the swept source OCT can be sampled based on the light reception result of the light receiving unit, the OCT optical system is used to monitor the light amount of the output light of the wavelength swept light source. There is no need to split light in the system. As a result, it is possible to suppress the loss of light amount and prevent the measurement accuracy and image quality from being lowered. Further, it is necessary to add an optical element for branching light, so that the configuration of the optical system can be simplified, and the size and cost of the apparatus can be reduced.

  In the light source control method according to some embodiments, the light source control step controls the amount of light based on the comparison result between the integration result obtained by integrating the light reception result and the threshold value.

  According to such a configuration, since the wavelength swept light source is controlled based on the integration result of the light reception result, the wavelength swept light source can be controlled with high accuracy even when the light reception result changes slightly. become.

  In the light source control method according to some embodiments, the light source control step performs output stop control or light amount reduction control of the wavelength swept light source when the light amount of the output light is equal to or greater than a predetermined threshold value.

  According to such a configuration, even when the amount of output light of the wavelength swept light source exceeds a threshold value, the amount of light irradiated to the object to be measured is reduced without causing an increase in the size of the optical system or a decrease in the amount of light. It becomes possible to control.

  In the light source control method according to some embodiments, the light source control step controls the amount of light based on a temporal change in the light reception result.

  According to such a configuration, the wavelength swept light source can be controlled based on the temporal change in the light amount of the output light of the wavelength swept light source, so that the details can be obtained without causing an increase in the size of the optical system and a decrease in the light amount. Light quantity control becomes possible.

  In the light source control method according to some embodiments, the light source control step controls the light amount based on the correlation between the reference change information stored in advance and the temporal change in the light reception result.

  According to such a configuration, the change in the output light of the wavelength swept light source can be analyzed based on the correlation with the reference change information defined in advance, so that the wavelength swept light source can be controlled with high accuracy.

  In the light source control method according to some embodiments, the light source control step performs output stop control of the wavelength swept light source when the correlation value between the reference change information and the temporal change in the light reception result is equal to or less than a threshold value.

  According to such a configuration, since the correlation value between the reference change information and the temporal change in the light reception result by the light receiving unit is calculated, the wavelength sweep light source can be controlled with high accuracy by a simple process. .

  In the light source control method according to some embodiments, the light source control step performs output stop control of the wavelength swept light source when the light reception result does not change for a predetermined period.

  According to such a configuration, even when the light amount of the output light from the wavelength swept light source does not change, more detailed light amount control can be performed without causing an increase in the size of the optical system or a decrease in the light amount.

  The embodiment described above is merely an example of the present invention. A person who intends to implement the present invention can arbitrarily make modifications (omission, replacement, addition, etc.) within the scope of the present invention.

  A program that causes a computer to execute the light source control circuit or the ophthalmologic apparatus control method according to the above-described embodiment is stored in the storage unit 212. Such a program may be stored in any recording medium readable by a computer. The recording medium may be an electronic medium using magnetism, light, magneto-optical, semiconductor, or the like. Typically, the recording medium is a magnetic tape, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, a solid state drive, or the like.

DESCRIPTION OF SYMBOLS 1 Ophthalmology apparatus 2 Fundus camera unit 3 Display apparatus 100 OCT unit 101 Light source unit 101A, 101B, 101C Light source control circuit 102, 301, 303, 312, 313, 351, 352 Optical fiber 210 Control part 211 Main control part 212 Storage part 300 Wavelength swept light source 302, 311, 314 Fiber coupler 310 Interference light generation unit 316, 353, 354 Lens 320, 360 Light receiving unit 330 Detection circuit 340, 380 Light source control unit 370 A / D converter 381 Storage unit 381A Reference waveform information

Claims (18)

A light source control device for controlling a wavelength swept light source,
An optical branching unit for branching the output light from the wavelength swept light source into a first output light and a second output light;
The first output light is branched into first branched light and second branched light, and the first branched light and the second branched light that have passed through optical paths having different optical path lengths are combined to generate combined light. A combined light generator;
A light receiving portion for receiving the combined light;
A light source controller that controls the amount of the output light based on a light reception result by the light receiver;
A light source control device. A detection unit that compares the integration result obtained by integrating the light reception result by the light receiving unit with a threshold value;
The light source control device according to claim 1, wherein the light source control unit controls the light quantity based on a comparison result obtained by the detection unit. 3. The light source according to claim 1, wherein the light source control unit performs output stop control or light amount reduction control of the wavelength swept light source when the light amount of the output light is equal to or greater than a predetermined threshold value. Control device. The light source control device according to claim 1, wherein the light source control unit controls the light amount based on a temporal change in a light reception result by the light receiving unit. A storage unit that stores in advance reference change information of a light reception result by the light receiving unit;
The light source control unit controls the light quantity based on a correlation between the reference change information stored in the storage unit and a temporal change in a light reception result by the light receiving unit. Light source control device. The said light source control part performs output stop control of the said wavelength sweep light source, when the correlation value of the said reference change information and the temporal change of the light reception result by the said light-receiving part is below a threshold value. The light source control device described. The light source control unit according to any one of claims 4 to 6, wherein the light source control unit performs output stop control of the wavelength swept light source when the light reception result does not change over a predetermined period. apparatus. The combined light generation unit includes a Mach-Zehnder interferometer, and outputs light output from the Mach-Zehnder interferometer as the combined light. Light source control device. The light source control apparatus according to any one of claims 1 to 8, wherein the light receiving unit includes a photodetector that receives the combined light. The light receiving unit receives a first light receiving element that receives the first combined light obtained by branching the combined light, and a second light receiving unit that receives the second combined light obtained by branching the combined light. The light receiving result of the said 1st light receiving element or the light receiving result of the said 2nd light receiving element is output including the balance detector containing an element. The Claim 1 characterized by the above-mentioned. Light source control device. The light source control device according to any one of claims 1 to 10,
Interference optics that divides the second output light into reference light and measurement light, irradiates the measurement eye with the measurement light, and detects interference light between the return light of the measurement light from the eye to be examined and the reference light The system,
Sampling the detection result of the interference light based on the light reception result by the light receiving unit, and forming an image of the eye to be examined based on the sampled detection result of the interference light;
An ophthalmic apparatus characterized by comprising: A light source control method for controlling a wavelength swept light source,
A light branching step for branching the output light from the wavelength swept light source into a first output light and a second output light;
The first output light is branched into first branched light and second branched light, and the first branched light and the second branched light that have passed through optical paths having different optical path lengths are combined to generate combined light. A synthetic light generation step;
A light receiving step for receiving the combined light;
A light source control step for controlling a light amount of the output light based on a light reception result in the light reception step;
A light source control method including: The light source control method according to claim 12, wherein the light source control step controls the light quantity based on a comparison result between an integration result obtained by integrating the light reception result and a threshold value. 14. The light source according to claim 12, wherein the light source control step performs output stop control or light amount reduction control of the wavelength swept light source when the light amount of the output light is equal to or greater than a predetermined threshold value. Control method. The light source control method according to claim 12, wherein the light source control step controls the light amount based on a temporal change in the light reception result. The light source control method according to claim 15, wherein the light source control step controls the light amount based on a correlation between reference change information stored in advance and a temporal change in the light reception result. The light source control step performs output stop control of the wavelength-swept light source when a correlation value between the reference change information and a temporal change in the light reception result is equal to or less than a threshold value. Control method. The light source control step according to any one of claims 12 to 17, wherein the light source control step performs output stop control of the wavelength swept light source when the light reception result does not change for a predetermined period. Method.

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