JP5629493B2 - Scanning laser imaging device - Google Patents

Description

  The present invention relates to a scanning type laser imaging apparatus that scans a subject to be photographed to photograph the subject to be photographed.

  Conventionally, an irradiation optical system that irradiates the eye fundus with a laser beam and scans the eye fundus two-dimensionally, and an observation optical system that receives reflected light reflected from the fundus and observes the fundus A scanning laser optometry apparatus provided is known (see Patent Document 1).

  Such a scanning laser optometry apparatus generally includes a focusing lens that can move in the direction of the optical axis, and the examiner moves the focusing lens while observing the fundus image displayed on the monitor to perform laser scanning. Focusing on the light.

Japanese Patent Laid-Open No. 2-84931

  However, in such a scanning laser optometry apparatus, the examiner determines whether or not the laser beam is focused from the fundus image displayed on the monitor. There was a variation, and there was a problem that it was not known whether the laser beam was actually focused on the fundus.

  An object of the present invention is to provide a scanning laser imaging apparatus capable of reliably focusing laser light on an object to be imaged.

According to the first aspect of the present invention, there is provided an irradiation optical system that condenses laser light emitted from a laser light source in a spot shape and scans the object to be imaged two-dimensionally, and reflected light from the object to be imaged or An observation optical system for observing the object to be imaged by receiving fluorescence from the object to be imaged, and the irradiation optical system includes a focusing optical system for focusing the laser beam on the object to be imaged In a scanning laser imaging apparatus having
Condensation detection means for detecting a spot diameter of laser light condensed on the object to be imaged ,
Focusing control means for controlling the focusing optical system based on the spot diameter detected by the condensing detection means to focus the laser beam is provided .

  According to the present invention, since the condensing detection means detects the condensing state of the laser light condensed on the object to be imaged, the laser light is reliably focused on the object to be imaged. Can do.

It is an optical layout diagram showing the layout of the optical system of the scanning laser optometry apparatus according to the present invention. It is a block diagram which shows the structure of the control system of the scanning laser optometry apparatus shown in FIG. It is explanatory drawing which showed the spot image of the out-of-focus state formed on the light receiving element. It is explanatory drawing which showed the spot image of the focused state formed on the light receiving element. It is the graph which showed the relationship between the position of a focusing lens, and a spot diameter. It is explanatory drawing which showed the screen displayed on the monitor before focusing is performed. It is explanatory drawing which showed the screen displayed on a monitor at the time of focusing. It is a block diagram which shows the structure of the control system of the scanning laser optometry apparatus of 2nd Example. It is explanatory drawing which showed the spot image in case astigmatism entered. It is explanatory drawing which showed the screen of the monitor of 2nd Example. It is explanatory drawing which showed the screen of the monitor at the time of focusing. It is explanatory drawing which showed the spot image when an astigmatic axis was correct | amended. It is explanatory drawing which showed the screen of the monitor when an astigmatic axis was correct | amended. It is a graph which shows a spot diameter and its average value. It is explanatory drawing which showed the relationship between a fundus and a focus position of a laser beam. It is explanatory drawing which showed typically the spot diameter of the laser beam on a fundus. It is explanatory drawing which calculated | required and displayed the average value of the spot diameter of FIG. 12B. It is the graph which showed the spot diameter, the average value of the peripheral part of the fundus, and the average value of the central part. It is the graph which showed the brightness | luminance of the spot image. It is an optical arrangement | positioning figure which showed the optical system of the principal part of the scanning laser optometry apparatus of 3rd Example. It is the block diagram which showed the structure of the control system of the scanning laser optometry apparatus of 3rd Example. It is explanatory drawing which showed the linear condensed light beam condensed linearly on the fundus. It is explanatory drawing which showed the linear condensed light beam image in the state where the laser beam is not focused. It is explanatory drawing which showed the linear condensed light beam image of the state by which the laser beam is focused. It is the graph which showed the relationship between the position of a focusing lens, and the convergence width of a laser beam.

  Hereinafter, an embodiment which is an embodiment of a scanning laser imaging apparatus according to the present invention will be described with reference to the drawings.

[First embodiment]
FIG. 1 shows a scanning laser optometry apparatus 10 which is a scanning laser imaging apparatus. The scanning laser optometry apparatus 10 includes a fundus illumination optical system 20 that illuminates the fundus (object to be photographed) Er of the eye E, a fundus photographing optical system 30 that photographs the fundus Er, and two laser beams on the fundus Er. Irradiation optical system 40 for scanning in dimension, observation optical system 60 for observing the fundus by receiving the reflected light beam of the laser beam reflected by the fundus Er, and focus detection for detecting the focus state of the laser beam An optical system 70 and a fixation target optical system 80 that projects the fixation target onto the fundus Er are provided.

  The fundus illumination optical system 20 includes a halogen lamp 21, a condenser lens 22, a ring aperture plate 23 having a ring aperture 23a at a conjugate position with the pupil of the eye E, a relay lens 24, a reflection mirror 25, and a relay lens. 26, a perforated mirror 27, and an objective lens 28.

  The fundus photographing optical system 30 includes an objective lens 28, a focusing lens (focusing optical system) 31 movable along the optical axis direction, a quick return mirror 32, relay lenses 33 and 34, a CCD, and the like. An image sensor 35. The image sensor 35 is disposed at a conjugate position with the fundus.

  The irradiation optical system 40 transmits a visible laser light source (laser light source) 41 that emits laser light with a wavelength of 488 nm, an infrared laser light source (laser light source) 42 that emits laser light with a wavelength of 790 nm, and a laser light with a wavelength of 488 nm. A dichroic mirror 43 that reflects laser light having a wavelength of 790 nm, a relay lens 44, a half mirror (50% transmission, 50% reflection) 45, a relay lens 46, a resonant scanner 47, a relay lens 48, and a galvano scanner. 49, a half mirror 50 that reflects only visible light having a wavelength of 650 nm, a relay lens 51, a focusing lens (focusing optical system) 31, and an objective lens 28.

  The observation optical system 60 includes an objective lens 28, a focusing lens 31, a relay lens 51, a half mirror 50, a galvano scanner 49, relay lenses 48 and 46, a resonant scanner 47, a half mirror 45, and a half mirror. A mirror (50% transmission, 50% reflection) 61, a relay lens 62, a confocal stop 63 disposed at a conjugate position with the fundus Er, a relay lens 64, and a light having a wavelength of 480 to 800 are reflected. It has a dichroic mirror 65 that transmits light of 550 nm, an image construction light receiving element 66 for infrared, and an image construction light receiving element 67 for visible light. The image construction light receiving elements (light receiving elements) 66 and 67 are CCDs or the like.

  The focusing detection optical system 70 includes an objective lens 28, a focusing lens 31, a relay lens 51, a half mirror 50, a galvano scanner 49, relay lenses 48 and 46, a resonant scanner 47, and a half mirror 45. , A half mirror 61, a relay lens 71, and a spot diameter measuring light receiving element (light receiving element) 72 made of a CCD or the like.

  The fixation target optical system 80 includes a fixation target light source 81 including a plurality of light emitting diodes arranged at a conjugate position with the fundus Er, a relay lens 82, a half mirror 50, a relay lens 51, and a focusing lens 31. And an objective lens 28. The fixation target light source 81 may be a single light emitting diode.

  The emission ends of the laser light sources 41 and 42 and the light receiving surfaces of the light receiving elements 66 and 67 are in a conjugate position with the fundus Er, and the emission end of the infrared laser light source 42 and the light receiving surface of the light receiving element 66 have an infrared wavelength. Is located at a position that is conjugate to the fundus Er. In addition, E1 shown with the broken line of FIG. 1 shows the conjugate position of the fundus Er.

  FIG. 2 is a block diagram showing the configuration of the control system of the scanning laser optometry apparatus 10. In FIG. 2, reference numeral 90 denotes an arithmetic circuit that calculates the diameter of the laser beam irradiated onto the fundus Er based on the light reception signal of the light receiving element 72. The arithmetic circuit 90 is a pixel in a range in which the light receiving element 72 receives light. Find based on the number.

   91 is a focus detection circuit that detects a focus state from the diameter of the laser beam obtained by the arithmetic circuit 90, 92 is a halogen lamp 21, a fixation target light source 81, laser light sources 41 and 42, based on the operation of the operation unit 94, This is a control device (control means) for controlling the galvano scanner 49, the resonant scanner 47, and the like. The control device 92 displays the fundus image formed on the image sensor 35 on the monitor (display means) 93 or constructs the fundus image from the received light signals received by the light receiving elements 66 and 67 and displays the fundus image on the monitor 93. The focusing lens 31 is moved from one end to the other end of the moving range, or the focusing lens 31 is moved based on the focusing state detected by the focusing detection circuit 91 to perform focusing.

  That is, the control device 92 has a function of an image construction unit 92A that constructs a fundus image and a function as a focusing control unit that moves the focusing lens 31 to perform focusing.

Further, the focus detection optical system 70, the arithmetic circuit 90, and the focus detection circuit 91 constitute a light collection detection means (focus detection means) for detecting the light collection state of the laser light.
[Operation]
Next, the operation of the scanning laser optometry apparatus 10 of the above embodiment will be described.

  Now, for example, a case where the fundus Er is scanned and observed with visible laser light will be described. In this case, the quick return mirror 32 is moved to the broken line position.

  First, after alignment is performed, the operation unit 94 is operated to turn on a desired light emitting diode of the fixation target light source 81 so that the visual axis of the eye to be examined Er is directed in a predetermined direction. Next, when the visible laser light mode is set by operating the operation unit 94 and a start switch (not shown) is operated, visible laser light is emitted from the visible laser light source 41, and this laser light is emitted from the dichroic mirror 43. Through the relay lens 44 and reaches the half mirror 45 where it is reflected and reaches the resonant scanner 47.

  The laser beam is scanned in the horizontal direction by the resonant scanner 47, and the laser beam scanned in the horizontal direction reaches the galvano scanner 49 via the relay lenses 46 and 48, and this laser beam is little by little in the vertical direction by the galvano scanner 49. It will be scanned.

  The laser light scanned by the galvano scanner 49 is incident on the eye E through the half mirror 50, the relay lens 51, the focusing lens 31, the hole 27a of the aperture mirror 27, and the objective lens 28, and the laser light is spot-like. Then, the fundus Er is scanned.

  The reflected laser light reflected from the fundus Er is the objective lens 28, the hole 27a of the aperture mirror 27, the focusing lens 31, the relay lens 51, the half mirror 50, the galvano scanner 49, the relay lens 48, the relay lens 46, and the resonant scanner. It reaches the half mirror 61 via 47 and the half mirror 45. Here, the reflected laser light is divided into two, and one of the two divided divided laser beams is transmitted through the half mirror 61 and visible light through the relay lens 62, the confocal stop 63, the relay lens 64, and the dichroic mirror 65. The image construction light-receiving element 67 receives the light.

  On the other hand, the other reflected laser beam divided into two is reflected by the half mirror 61 and received by the light receiving element 72 via the relay lens 71.

  The image constructing unit 92A of the control device 92 constructs a fundus image according to the scanning of the resonant scanner 47 and the galvano scanner 49 based on the amount of light received by the light receiving element 67, and the constructed fundus image is monitored 93. To display.

  On the other hand, the arithmetic circuit 90 calculates a diameter (spot diameter) on the fundus Er of the laser light focused in a dotted manner on the fundus Er based on the light received by the light receiving element 72.

  The diameter of the laser beam is obtained from the number of pixels in the vertical and horizontal directions of the spot image S of the light receiving element 72 as shown in FIG. 3A. 3A shows the spot image S when the laser beam is not focused, and FIG. 3B shows the spot image Sa when the laser beam is focused. Note that the position of the spot image S of the light receiving element 72 is formed at a fixed position regardless of the scanning of the laser beam, but the size of the spot image S changes according to the scanning position of the laser beam. .

  The control device 92 moves the focusing lens 31 from one end to the other end of the moving range, and the spot diameter of the laser light calculated by the arithmetic circuit 90 is made to correspond to the moving position of the focusing lens 31 as shown in FIG. I will ask for it. Here, the average spot diameter is obtained for the moving position of the focusing lens 31.

  Since the spot diameter varies depending on the scanning position on the fundus, the average value is obtained.

  And the control apparatus 92 calculates | requires the minimum spot diameter which becomes the minimum from the average spot diameter shown in FIG.

  Further, the control device 92 determines an allowable value (minimum spot diameter + α) from the minimum spot diameter.

  On the other hand, as shown in FIG. 5, the fundus image Gr constructed by the image construction unit 92 </ b> A and a focused display image Ga for displaying the focused state are displayed on the monitor 93.

  The focus display image Ga includes a scale image Ga1 indicating the focus area E1 and the non-focus area E2, a cursor image K indicating the focus state, and the like. The cursor image K is moved up and down with respect to the scale image Ga1 according to the in-focus state, that is, according to the difference between the minimum spot diameter and the laser beam spot diameter.

  That is, the larger the difference is, the lower the cursor image K is displayed, and as the difference becomes smaller, the cursor image K is moved upward and displayed as shown in FIG. FIG. 5 shows an example when the laser beam is not focused, and FIG. 6 shows an example when the laser beam is focused.

  When determining the allowable value, the control device 92 moves the focusing lens 31 from the other end to the one end. During this movement, the focus detection circuit 91 obtains a difference (in-focus state) between the spot diameter calculated by the arithmetic circuit 90 and an allowable value, and when this difference becomes zero, that is, the laser beam diameter is allowable. When the value falls within the value, the control device 92 stops the movement of the focusing lens 31. At this time, the focused display image Ga shown in FIG.

  Thereafter, the fundus image constructed by the image construction unit 92A of the control device 92 is a properly focused fundus image, and this fundus image is displayed on the monitor 93. This fundus image is recorded in a memory (not shown) as necessary.

  In this way, the focusing lens 31 is moved from one end to the other end to obtain the minimum spot diameter, and then the focusing lens 31 is moved until the difference between the spot diameter of the laser beam and the minimum spot diameter becomes a predetermined value or less. Since focusing is performed by moving from one end to the other, the laser beam can be reliably focused on the fundus, and it is possible to prevent the focused state from being mixed by the examiner. it can.

  Further, since it is not necessary to provide a focus index projection optical system for projecting the focus index onto the fundus Er for focusing, the scanning laser optometry apparatus 10 can be reduced in size and weight. Further, since the focus of the laser beam is not determined based on the brightness of the reflected light from the fundus Er, the focus of the laser beam can be reliably performed.

  In this embodiment, the focusing lens 31 is automatically moved by the control device 92 in the focusing direction. However, when the focusing lens 31 is configured to move manually, the focusing lens 31 shown in FIGS. 5 and 6 is used. The focus display image Ga is useful.

  Even when the infrared mode is set and the infrared laser light is emitted from the infrared laser light source 42, the minimum spot diameter is obtained or focused in the same manner as described above, and the description thereof will be omitted.

  In the case of infrared light, an image of the choroid under the retina is observed. For this reason, the light receiving element 72 is moved to a position conjugate with the choroid position on the fundus Er or a compensation plate (not shown) is provided in the optical path. ) To conjugate the light receiving element 72 and the choroid of the fundus Er.

In the first embodiment, the focusing lens 31 is moved from one end to the other end in order to obtain the minimum spot diameter. If the minimum spot diameter is obtained during the movement, the focusing lens 31 is obtained at that time. The focusing lens 31 may be moved to the in-focus position by stopping the movement and slightly moving in the opposite direction.
[Second Embodiment]
FIG. 7 is a block diagram showing the configuration of the control system of the scanning laser optometry apparatus of the second embodiment.

  In FIG. 7, reference numeral 100 denotes a pair of cross cylinder lenses disposed so as to be rotatable around the optical axis. The cross cylinder lens 100 is disposed between the half mirror 45 and the resonant scanner 47 as indicated by a broken line in FIG. Be placed.

  190 is an arithmetic circuit for obtaining the direction and length of the major axis diameter and minor axis diameter of the laser light condensed on the fundus Er, and 191 is the length of the major axis or minor axis diameter obtained by the arithmetic circuit 190 and the minimum length. This is a focus detection circuit for obtaining a difference from the shaft diameter or the minimum short shaft diameter.

  The focus detection optical system 70 (see FIG. 1), the arithmetic circuit 190, and the focus detection circuit 191 constitute a light collection detection means (focus detection means) for detecting the laser light collection state.

  The control device 192 obtains the minimum major axis diameter or the smallest minor axis diameter, which is the smallest of the major axis diameter or the minor axis diameter obtained by the arithmetic circuit 190 when the focusing lens 31 is moved, as the minimum spot diameter. Then, an allowable value (minimum spot diameter + α) is determined from the minimum spot diameter.

  Further, the control device 192 rotates the cross cylinder lens 100 based on the direction of the major axis diameter, so that the major axis diameter and the minor axis diameter are substantially the same, that is, the spot is almost in a perfect circle state.

  As shown in FIG. 9, the monitor 193 displays an astigmatism image DS2 indicating an astigmatism state on the astigmatism display unit 2Ga, and “OK” indicating whether or not the correction display unit 2Gb has completed correction of astigmatism (see FIG. 11). And “NG” are displayed.

The cursor image K is displayed in the same manner as in the first embodiment depending on the difference between the minimum major axis diameter and the major axis diameter or the difference between the minimum minor axis diameter and the minor axis diameter.
[Operation]
Next, the operation of the scanning laser optometry apparatus according to the second embodiment will be described.

  Visible laser light is emitted from the visible laser light source 41 in the same manner as in the first embodiment, and this laser light is scanned on the fundus Er by the resonant scanner 47 and the galvano scanner 49. Then, the laser beam reflected by the fundus Er is received by the image construction light receiving element 67 and the light receiving element 72, and the image construction unit 92A of the control device 192 constructs a fundus image based on the amount of light received by the light reception element 67. The constructed fundus image is displayed on the monitor 193.

  When the subject's eye has an astigmatism axis, the spot shape of the laser light condensed on the fundus Er is elliptical, and an elliptical spot image S2 is formed on the light receiving element 72 as shown in FIG. .

  The arithmetic circuit 190 obtains the major axis diameter and the minor axis diameter of the spot diameter of the laser light based on the spot image S2 formed on the center portion of the light receiving element 72.

  For example, when the spot image S2 is scanned in the horizontal direction sequentially from the top, the position of the center of gravity in the horizontal direction is sequentially determined from the light receiving amount of each pixel of the spot image S2 in the horizontal direction. A line SL1 in a direction connecting the positions is obtained. The line SL1 indicates the major axis diameter of the ellipse, and the major axis diameter SL1 indicates the astigmatic axis. Further, the position of the center of gravity is determined in the same manner as described above along the direction orthogonal to the length of the long axis diameter SL1 at a position that is 1/2 of the long axis diameter SL1, and a line SL2 connecting the positions of the center of gravity is determined. This line SL2 indicates the minor axis diameter.

  The control device 192 moves the focusing lens 31 from one end of the moving range to the other end, obtains the major axis diameter SL1 of the spot image S2 at each position of the focusing lens 31, and determines the minimum of these. The minimum major axis diameter SL1a is obtained. Then, an allowable value (SL1a + α) is determined from the minimum major axis diameter SL1a.

  On the other hand, the image construction unit 92A of the control device 192 constructs a fundus image based on the amount of light received by the light receiving element 67, and astigmatism based on the constructed fundus image Gr and the spot image S2 on the light receiving element 72. The image DS2 and “NG” indicating that the correction of astigmatism is not completed are displayed on the monitor 193 as shown in FIG. Further, since focusing is not yet performed in this state, a focused display image Ga in which the cursor image K is positioned in the non-focused area E2 is displayed on the monitor 193 as shown in FIG.

  When determining the allowable value, the control device 192 moves the focusing lens 31 from the other end to the one end. During this movement, the focus detection circuit 191 obtains a difference between the major axis diameter SL1 calculated by the arithmetic circuit 190 and the minimum major axis diameter SL1a, and moves the cursor image K of the focus display image Ga according to this difference. I will let you. When this difference is less than or equal to a predetermined value (α or less), that is, when focused, the major axis diameter SL1 of the laser beam spot falls within the allowable value, and the control device 192 stops the movement of the focusing lens 31.

  At this time, as shown in FIG. 9A, the cursor image K of the focus display image Ga is moved to the focus area E1 and displayed on the monitor 193.

  The examiner finds that the subject's eye E has astigmatism from the astigmatism image DS2 on the monitor 193, and operates an astigmatism axis correction switch (not shown) of the operation unit 94.

  By this operation, the control device 192 rotates the pair of cross cylinder lenses 100 in the direction of correcting astigmatism based on the direction of the major axis diameter SL1 of the spot image S2 (astigmatic axis direction).

  During this rotation, the focus detection circuit 191 obtains the difference between the major axis diameter SL1 and the minor axis diameter SL2 of the spot image S2 calculated by the arithmetic circuit 190, and when this difference becomes a predetermined value or less, the control device Reference numeral 192 stops the rotation of the cross cylinder lens 100.

  Since the spot of the laser beam is corrected by the cross cylinder lens 100, a substantially perfect spot image S2a is formed on the light receiving element 72 as shown in FIG.

  Further, when the correction of astigmatism is completed, the control device 192 displays a substantially circular image DS2a on the astigmatism display unit 2Ga of the monitor 193 as shown in FIG. 11, and displays the characters “OK” on the correction display unit 2Gb.

  By these displays, the examiner will know sensoryly and visually that the astigmatism has been corrected.

  Since the laser beam is focused and the astigmatism is corrected, the spot diameter of the laser beam that scans on the fundus Er becomes the smallest and close to a perfect circle. The fundus image thus obtained becomes clearer and is displayed on the monitor 193.

  Even when the infrared mode is set and the infrared laser light is emitted from the infrared laser light source 42, the long axis diameter and the short axis diameter are obtained in the same manner as described above, focusing is performed, the astigmatic axis Will not be described. In this case, the compensation plate is placed in the optical path as in the first embodiment.

  According to the second embodiment, the laser beam can be reliably focused on the fundus even if there is an astigmatic axis, and it is possible to prevent the focused state from being mixed by the examiner.

  In the second embodiment, the focus of the laser beam is obtained from the difference between the major axis diameter and the minimum major axis diameter, but may be obtained from the difference between the minor axis diameter and the smallest minor axis diameter.

  In any of the above-described embodiments, the minimum spot diameter, the minimum long axis diameter, and the minimum short axis diameter are obtained from the diameter of the laser beam that scans the vicinity of the site (fovea) on the optical axis O1 of the fundus Er, and this is used as a reference. Although the allowable value is determined, for example, the focusing lens 31 is positioned at the position where the minimum spot diameter is obtained, and the average value of the spot diameters of the laser beams formed in each part of the fundus Er in this state The minimum major axis diameter (minimum minor axis diameter) is obtained as shown in FIG. 12, and an allowable value (average) based on this average value (spot diameter average value: minimum major axis diameter (minimum minor axis diameter) average value). The value + α) may be determined.

  By the way, as shown in FIG. 12A, the peripheral portion Erb has a lower aberration of the laser beam than the central portion Era (near the optical axis) of the fundus Er. Therefore, when focusing is performed at the central portion Era, the peripheral portion In Erb, the in-focus state may be greatly shifted. However, as shown in FIG. 12B, the diameter (spot diameter) of the spot d in each part of the light receiving element 72 after one scan is obtained, the average value of the spot diameters is obtained, and the average value of the spot diameters is obtained. If focusing is performed on the basis, the diameter of the spot d in each part of the light receiving element 72 becomes substantially the same spot diameter as shown in FIG. 12C, and the entire fundus Er can be focused.

  That is, when focusing on the position of the central portion Era shown in FIG. 12A, the focusing is greatly shifted in the peripheral portion. When focusing on the position of Eg, the focusing portion is focused on the peripheral portion of the fundus oculi Er. Although the focus is greatly deviated, focusing on the position of Ed, which is in the middle, makes it possible to focus on the entire fundus Er.

  Further, as shown in FIG. 13, the average value of the spot diameter at the center of the fundus oculi Er (average value of the center) and the average value of the spot diameter of the periphery of the fundus oculi Er (average value of the periphery) are obtained. When observing the central part of the eye, an allowable value (central part average value + α) is determined based on the central part average value, and when observing the peripheral part of the fundus Er, the peripheral part average value is used as a reference. A value (peripheral average value + α) may be determined.

  Similarly, in the case of astigmatism, the average values of the major axis and the minor axis of the center and the periphery of the fundus Er are respectively obtained, and the allowable value of the center of the fundus Er and the allowable value of the periphery are determined.

Further, a position detecting means for obtaining the position of the focusing lens 31 is provided, and the focusing lens 31 is moved when the focusing lens 31 is moved from one end to the other end to obtain the minimum spot diameter, the minimum long axis diameter, and the minimum short axis diameter. The position 31 and the size of the spot diameter, the major axis diameter, and the minor axis diameter are obtained, and when an allowable value is determined, a position corresponding to the allowable value is obtained, and the focusing lens 31 may be moved to this position. . In this case, when the focusing lens 31 is moved to that position, it is not necessary to obtain the spot diameter, the major axis diameter, and the minor axis diameter, and therefore the focusing lens 31 can be moved quickly.
[Third embodiment]
FIG. 15 shows the irradiation optical system 240, the observation optical system 260, and the focus detection optical system 270 of the scanning laser optometry apparatus of the third embodiment.

  The irradiation optical system 240 transmits a visible laser light source (laser light source) 41 that emits laser light with a wavelength of 488 nm, an infrared laser light source (laser light source) 42 that emits laser light with a wavelength of 790 nm, and a laser light with a wavelength of 488 nm. A dichroic mirror 43 that reflects laser light having a wavelength of 790 nm, a cylindrical lens 244, a half mirror (50% transmission, 50% reflection) 45, a relay lens 246, a galvano scanner 247, and the like.

  The irradiation optical system 240 condenses the laser light emitted from the laser light sources 41 and 42 into a linear shape by the cylindrical lens 244, and scans the laser light condensed in the linear shape onto the fundus Er by the galvano scanner 247. I will let you. The scanning direction is a direction orthogonal to the linear longitudinal direction, and in this embodiment is the vertical direction in FIG.

  The observation optical system 260 includes a galvano scanner 247, a relay lens 246, half mirrors 45 and 61, a relay lens 62, an image construction light receiving element (light receiving element) 261 arranged at a conjugate position with the fundus Er, and the like. doing. The image construction light receiving element 261 is a line sensor including a CCD having sensitivity to infrared light and visible light.

  The focus detection optical system 270 includes a galvano scanner 247, a relay lens 246, half mirrors 45 and 61, a relay lens 71, and a light receiving element (detecting the condensing state of laser light condensed on the fundus Er. Condensing detection means) 272 and the like. The light receiving element 272 includes a CCD having sensitivity to infrared light and visible light.

  The scanning laser optometry apparatus according to the third embodiment includes the fundus illumination optical system 20, the fundus photographing optical system 30, the fixation target optical system 80, and the like according to the first embodiment shown in FIG.

  FIG. 16 is a block diagram showing the configuration of the control system of the scanning laser optometry apparatus of the third embodiment.

In FIG. 16, reference numeral 290 denotes an arithmetic circuit for calculating the width of the laser light linearly focused on the fundus Er based on the light received by the light receiving element 272, and reference numeral 291 is focused from the width of the laser light calculated by the arithmetic circuit 290. A focus detection circuit (condensation detection means) 292 for detecting (condensation state) is a control device for constructing a fundus image from a light reception signal received by the light receiving element 261 and displaying it on the monitor 93. Control similar to that of the control device 92 of one embodiment is performed. That is, the control device 292 has a function of an image construction unit 292A that constructs a fundus image and a function as a focusing control unit that moves the focusing lens 31 to perform focusing.
[Operation]
Next, the operation of the scanning laser optometry apparatus of the third embodiment will be described.

  Now, for example, when visible laser light is emitted from the visible laser light source 41 shown in FIG. 15, the laser light passes through the dichroic mirror 43 and reaches the cylindrical lens 244, where the laser light is focused on the line. The condensed laser light reaches the galvano scanner 247 via the half mirror 45 and the relay lens 246.

  Here, the laser beam condensed on the line is scanned in the vertical direction (vertical direction) by the galvano scanner 247.

  As shown in FIG. 1, the laser beam scanned by the galvano scanner 247 enters the eye E through the half mirror 50, the relay lens 51, the focusing lens 31, the hole 27a of the aperture mirror 27, and the objective lens 28. As shown in FIG. 17, the laser beam is condensed linearly on the fundus Er, and the linear condensed light beam Rf collected on this line scans the fundus Er up and down. The quick return mirror 32 has been moved to the broken line position.

  The reflected laser light reflected from the fundus Er by the linear condensed light beam Rf is the objective lens 28, the hole 27a of the aperture mirror 27, the focusing lens 31, the relay lens 51, the half mirror 50, the galvano scanner 247, the relay lens. It reaches the half mirror 61 via 246 and the half mirror 45. Here, the reflected laser beam is divided into two, and one of the two divided laser beams is reflected by the half mirror 61 and received by the image construction light receiving element 272 via the relay lens 71.

  On the other hand, the other reflected laser beam divided into two passes through the half mirror 61 and is received by the light receiving element 261 through the relay lens 62.

  The image construction unit 292A of the control device 292 constructs a fundus image according to the scanning of the galvano scanner 247 based on the amount of light received by the light receiving element 261, and displays the constructed fundus image on the monitor 93.

  On the other hand, the arithmetic circuit 290 calculates the width of the laser light focused linearly on the fundus Er based on the light received by the light receiving element 272.

  Here, as shown in FIG. 18, the width Wa of the linear condensed light flux image Rfa formed on the light receiving element 272 is obtained. Since the width Wa differs depending on the position in the longitudinal direction of the linear condensed light flux image Rfa, an average value W (average width) of the width Wa at each position is obtained. The average width W is, for example, a value obtained by dividing the total area of pixels in which the light receiving element 272 receives the linear condensed light flux image Rfa divided by the length of the linear condensed light flux image Rfa.

  18 shows a linear condensed light beam image Rfa in a state where the laser light is not focused, and FIG. 19 shows a linear condensed light beam image Rfb in a state where the laser light is in focus.

   The control device 292 moves the focusing lens 31 from one end to the other end of the moving range, and the average width W of the linear condensed light flux image Rfa calculated by the arithmetic circuit 290 corresponds to the moving position of the focusing lens 31. As shown in FIG. Then, the control device 292 obtains the minimum width Ws that minimizes the average width W shown in FIG. Further, the control device 292 determines an allowable value (minimum width Ws + α) from the minimum width Ws.

  When determining the allowable value, the control device 292 moves the focusing lens 31 from the other end to the one end. During this movement, the focus detection circuit 291 causes the average width W calculated by the arithmetic circuit 290 and the allowable value. When the difference becomes zero, that is, when the width of the linear condensed light flux image Rfa falls within the allowable value, the control device 292 stops the movement of the focusing lens 31. .

  That is, the laser beam is focused, and the width of the linear condensed light beam Rf formed on the fundus Er shown in FIG. 17 is narrowed, and the linear condensed light beam image Rfb is formed on the light receiving element 272 as shown in FIG. Is formed.

  Thereafter, the fundus image constructed by the image construction unit 292A of the control device 292 is a properly focused fundus image, and this fundus image is displayed on the monitor 93.

  In the same manner as the first embodiment, the third embodiment displays the in-focus display image Ga on the monitor 93 as shown in FIGS. 5 and 6, and the same effect as the first embodiment can be obtained.

  In the third embodiment, the width of the linear condensed light flux image Rfa is regarded as constant with respect to the scanning of the laser light, and the average value of the width of the linear condensed light flux image Rfa is obtained. Since the width of the linear condensed light flux image Rfa varies depending on the light scanning position, an average value may be obtained for each scanning position, and the average value may be obtained from the width (average value) of each scanning position.

In any of the above-described embodiments, the focusing lens 31 is moved in the optical axis direction to focus the laser beam. However, the present invention is not limited to this. For example, a deformable mirror (wavefront correction element) is used as the focusing optical. It may be used as a system to focus laser light.
[Other examples]
In the above embodiment, the spot diameter is obtained from the size of the spot image formed on the light receiving element 72, but may be obtained from the brightness of the spot image. In this case, the luminance of the spot image formed on the light receiving element 72 is obtained corresponding to the time as shown in FIG. And average brightness | luminance is calculated | required and an average spot diameter (reference | standard spot diameter) is calculated | required from this average brightness | luminance.

  Here, a predetermined amount d (about 10%) is cut as a threshold value from the obtained luminance to obtain the average luminance Ka.

  This is because the spot image formed on the light receiving element 72 changes only in size without changing the position of the spot image on the light receiving element 72 according to the scanning position of the laser light on the fundus. This is because when measuring the diameter of a spot image, it is affected by the size of the spot image immediately before the measurement, and this effect is removed. Note that the spot diameter is obtained based on the average brightness Ka from the relationship that the brightness decreases as the spot diameter increases and the brightness increases as the spot diameter decreases.

  In any of the above-described embodiments, the scanning laser optometry apparatus that images the fundus oculi Er has been described. However, the present invention is not limited thereto, and may be a scanning laser imaging apparatus that images other parts or other objects.

  The present invention is not limited to the above-described embodiments, and design changes and additions are permitted without departing from the spirit of the invention according to each claim of the claims.

31 Focusing optical system (focusing lens)
40 Irradiation optical system 41 Visible laser light source (laser light source)
42 Infrared laser light source (laser light source)
60 Observation optical system 70 Focus detection optical system

Claims (11)

An irradiation optical system that condenses laser light emitted from a laser light source in a spot shape and scans the object to be imaged two-dimensionally, and reflected light from the object to be imaged or from the object to be imaged A scanning laser imaging apparatus having a focusing optical system for receiving the fluorescence and observing the object to be imaged, wherein the irradiation optical system focuses the laser light on the object to be imaged ,
Condensation detection means for detecting a spot diameter of laser light condensed on the object to be imaged ,
A scanning laser imaging apparatus comprising: a focusing control unit configured to control the focusing optical system based on the spot diameter detected by the condensing detection unit to focus the laser beam . The focusing optical system has a focusing lens that moves along the optical axis direction of the irradiation optical system;
The focusing control means moves the focusing lens from one end of the moving range to the other end,
The condensing detection means obtains a minimum diameter at which a spot diameter of laser light condensed on the object to be photographed by movement of the focusing lens is minimized,
Thereafter, the focusing control means moves the focusing lens to a position where the difference between the spot diameter of the laser beam on the object to be imaged and the minimum diameter is within a predetermined range. Item 2. A scanning laser imaging apparatus according to Item 1. 3. The scanning laser imaging apparatus according to claim 2, wherein the minimum diameter is an average value of the minimum diameters of the spot lights of the laser light at each part on the object to be imaged . 4. The scanning according to claim 3 , wherein a range on the object to be photographed for determining focus can be arbitrarily set, and a minimum diameter of the spot light of the laser beam is obtained in the set range. Type laser imaging device. The scanning laser imaging apparatus according to claim 4 , wherein the minimum diameter of the spot light of the laser light is an average value within the set range . An irradiation optical system that condenses laser light emitted from a laser light source in a spot shape and scans the object to be imaged two-dimensionally, and reflected light from the object to be imaged or from the object to be imaged A scanning laser imaging apparatus having a focusing optical system for receiving the fluorescence and observing the object to be imaged, wherein the irradiation optical system focuses the laser light on the object to be imaged ,
Condensation detection means for detecting the major axis diameter of the spot diameter of the laser beam condensed on the object to be imaged;
A scanning laser imaging apparatus comprising: a focusing control unit configured to control the focusing optical system based on a major axis diameter detected by the condensing detection unit to focus the laser beam. . The object to be imaged is the fundus of the eye to be examined;
A short axis diameter of a spot diameter of the laser beam condensed on the fundus is obtained, an astigmatism state is obtained based on the short axis diameter and the major axis diameter, and the astigmatism state is displayed on a display unit, The scanning laser apparatus according to claim 6. Astigmatic axis correcting means having a pair of cross cylinder lenses rotatable around the optical axis and correcting the long axis diameter and the short axis diameter of the laser beam to be the same by rotating the pair of cross cylinder lenses The scanning laser imaging apparatus according to claim 7 , wherein: An irradiation optical system for condensing laser light emitted from a laser light source into a linear shape and scanning the object to be imaged in a direction orthogonal to the linear direction, and reflected light from the object to be imaged or the object An observation optical system for observing the object to be photographed by receiving fluorescence from the object to be photographed, and the irradiation optical system has a focusing optical system for focusing the laser light on the object to be photographed In the scanning laser imaging apparatus,
Condensation detecting means for detecting the line width of the laser beam condensed linearly on the object to be imaged,
A scanning laser comprising: a focusing control unit that controls the focusing optical system based on a line width of the laser beam detected by the condensing detection unit and performs focusing of the laser beam. Shooting device. The focusing optical system has a focusing lens that moves along the optical axis direction of the irradiation optical system;
The focusing control means moves the focusing lens from one end of the moving range to the other end,
The condensing detection means obtains a minimum width at which the line width of the laser beam condensed linearly on the object to be imaged by the movement of the focusing lens is minimized,
Thereafter, the focusing control means moves the focusing lens to a position where the difference between the convergence width of the laser beam on the object to be imaged and the minimum width is within a predetermined range. Item 10. A scanning laser imaging apparatus according to Item 9. The scanning laser imaging apparatus according to claim 10, wherein the minimum width is an average value of widths at respective positions with respect to the length of the laser beam condensed linearly .

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