JP5483989B2 - Ophthalmic equipment - Google Patents

Description

  The present invention relates to an ophthalmologic apparatus that performs alignment in a predetermined positional relationship with an eye to be examined when measuring the eye to be examined.

  In ophthalmic examinations, an apparatus that performs alignment (positioning) on an eye to be examined by moving an optometric part relative to a fixed base while observing an image of the eye to be examined on a monitor is the mainstream.

  As an alignment mechanism of this type of apparatus, an alignment index is projected from the visual axis direction of the eye to be examined, and a reflected bright spot near the corneal apex formed by corneal reflection is imaged by a TV camera and displayed on an observation TV monitor. This is known. The operator performs alignment adjustment in the vertical and horizontal directions by introducing the corneal reflection bright spot described above to a predetermined position of the TV monitor. In addition, alignment in the working distance (front-rear) direction is performed by focusing on the corneal reflection bright spot. In recent years, a device has appeared that detects a reflection image of the above-described index light beam with a light receiving element and automatically performs alignment based on the detection result.

  However, in an apparatus that performs alignment based on the result of detecting the reflected image of the index light beam by the light receiving element, disturbance light other than the index light beam is incident on the light receiving element during alignment adjustment. May cause erroneous operation in alignment adjustment.

In order to solve the above-described problem, first detection means for detecting the alignment state of the eye to be inspected by causing the corneal reflection light beam of the alignment index light to enter the position detection element capable of detecting the center of gravity position of the incident light beam, and the light amount of the incident light beam And a second detection means for detecting the alignment state of the eye to be inspected by causing the corneal reflection light beam to enter the light quantity detection element capable of detecting the light amount, and based on the detection results of the first detection means and the second detection means. Japanese Patent Application Laid-Open No. H10-228707 discloses an apparatus including a determination unit that determines whether the light is an alignment index light or disturbance light.
However, this apparatus requires a light amount detection element in addition to a position detection element that detects the position of the corneal reflected light beam as an alignment index, and thus there is a problem that the configuration becomes complicated as the number of parts increases and the manufacturing cost increases.

JP 11-318828 A

  The present invention has been made in view of the above circumstances, and in an ophthalmologic apparatus that acquires an alignment state between an apparatus and a subject's eye from an observation image of the subject's eye, alignment adjustment is performed by eliminating the influence of ambient light incident on the position detection element. Provided is a device capable of preventing malfunction of the device.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

A first aspect of the ophthalmologic apparatus according to the present invention is an optometry unit incorporating an optometry optical system for inspecting or measuring an eye to be examined, a moving means for moving the optometry unit three-dimensionally, and illuminating the eye to be examined. A plurality of illumination light sources, an observation optical system for receiving and observing an eye image illuminated by the plurality of illumination light sources on an image sensor, display means for displaying the eye image received on the image sensor, and Light source lighting control means for blinking the plurality of illumination light sources in synchronization with a control signal of the image sensor, and a reflection image of the illumination light source superimposed on the eye image to be detected by a two-dimensional position detection element to detect the optometry unit And at least a part of acquiring the alignment state of the eye to be inspected includes an alignment state acquisition unit that is also used as the observation optical system, and is detected by the alignment state acquisition unit. The ophthalmic apparatus which performs the movement of the eye unit based on the alignment state, the light source lighting control means for lighting the first state and the total number of turns on the half of the plurality of illumination light sources in the imaging cycle of the imaging element When the state of 2 is switched and the transition to the next imaging cycle is performed, control is performed so that turning on and off of the first state is reversed, and the alignment state acquisition unit is configured for each period corresponding to the imaging cycle of the imaging device. The alignment state is acquired based on information obtained by subtracting two signals output from the two-dimensional position detecting element.

According to a second aspect of the ophthalmic apparatus of the present invention, in the ophthalmic apparatus according to the first aspect, switching between the first state and the second state is synchronized with field switching of the image sensor or electronic shutter timing. It is characterized by being performed.

According to a third aspect of the ophthalmologic apparatus of the present invention, in the ophthalmologic apparatus according to the first or second aspect, the plurality of illumination light sources are arranged at positions that are point-symmetric with respect to the optical axis of the optometry optical system. The two-dimensional position detection element is arranged so as to be inclined by 45 ° with respect to a straight line connecting the light source that is turned on and the light source that is turned off in the first state.

According to a fourth aspect of the ophthalmologic apparatus of the present invention, in the ophthalmologic apparatus according to the first to third aspects, the imaging element is also used as the two-dimensional position detection element.

  According to the present invention, it is possible to extract only a signal originating from the light source that illuminates the eye to be examined from the signal output from the two-dimensional position detection element of the alignment information detection means. It becomes unnecessary to identify disturbance light.

  In addition, according to the present invention, by turning on the plurality of light sources that illuminate the eye to be examined and synchronizing the timing of acquiring signals from the two-dimensional position detection element with the imaging cycle of the imaging element that receives the observation image of the eye to be examined, Since it is possible to suppress the flickering of the display screen due to the lighting control of the light source, it is possible to reduce the burden on the operator who watches the display screen in the alignment operation.

It is an external view of the ophthalmologic apparatus which is embodiment of this invention. It is a figure which shows the optical power measurement optical system which is an example of the optical system accommodated in the optometry part of the ophthalmologic apparatus which is embodiment of this invention. It is a block diagram which shows control of the ophthalmologic apparatus which is embodiment of this invention. It is a flowchart in connection with control of the illumination light source which observes a to-be-tested eye, and CCD for observation. It is a timing chart regarding control of the illumination light source which observes a to-be-tested eye, and CCD for observation. It is a flowchart in connection with alignment control. It is an observation image of the eye to be examined that is observed on a monitor when illuminated with four illumination light sources. It is a figure which shows the example of the luminance distribution of the eye to be examined light-received by CCD for observation. It is the figure which showed the projection data of the luminance distribution information of the eye to be examined received by CCD for observation. It is the figure which showed the relationship of the detection range of the two-dimensional position detection element with respect to the display screen of a monitor. It is the figure which showed the projection data of the luminance distribution information detected by a two-dimensional position detection element. It is the figure which showed the positional relationship of the cylindrical lens and the two-dimensional position detection element seen from the optical axis direction of the alignment optical system, and the reflected image of the illumination light source guide | induced to a two-dimensional position detection element. It is explanatory drawing of the alignment optical system employ | adopted in order to detect the alignment state of a Z direction. It is the figure which showed the change of the detection information of the two-dimensional position detection element accompanying the change of the alignment state of a Z direction. It is the figure which showed the relationship between the output of a two-dimensional position detection element, and the alignment state of the front-back (Z) direction when the position of a left-right up-down (XY) direction is appropriate. It is the figure which showed the relationship between the output of a two-dimensional position detection element when the position of a left-right and up-down (XY) direction is not appropriate, and the alignment state of the front-back (Z) direction. It is the figure which showed the relationship between the output of a two-dimensional position detection element when the position of the front-back (Z) direction is appropriate, and the alignment state of the left-right up-down (XY) direction. It is an observation image of the eye to be examined that is observed on a monitor when illuminated with two illumination light sources. 6 is a timing chart relating to control of an illumination light source for observing an eye to be examined and an interline observation CCD when a two-dimensional position detection element is not used.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic external view of an eye refractive power measuring apparatus according to an embodiment. Reference numeral 1 denotes a main body, and a chin rest unit 2 for fixing an eye to be examined is fixed to the main body 1. Reference numeral 3 denotes an optometry unit that houses an optical system to be described later. Reference numeral 4 denotes a joystick for moving the optometry unit 3. The joystick 4 includes a lever part 4A that can slide and move in a horizontal direction within a predetermined range with respect to the main body part 1, a plate part 4B that can slide in a horizontal direction, and a rotatable ring part 4C. . A measurement switch 5 is provided at the tip of the joystick 4. Inside the main body 1, there are provided detection means for detecting the amount of movement due to the above-described tilting, sliding and rotation of 4A to C, and driving means for moving the optometry part 3 in accordance with the amount of movement, and a joystick 4, the optometry unit 3 moves in the left-right direction (X direction), the up-down direction (Y direction), and the front-rear direction (Z direction) with respect to the main body unit 1. For details, refer to Japanese Patent Application Laid-Open No. 2006-130227 filed by the present applicant. An operation panel 6 is a collection of switches for performing various settings. Reference numeral 7 denotes a monitor for displaying information on alignment and measurement. Here, the information regarding the alignment includes an observation image of the eye to be examined.

FIG. 2 shows an optical system for measuring the refractive power of the eye E as an example of the optical system housed in the optometry unit 3. The optical system shown here includes an observation optical system 20 that observes the eye E, an alignment optical system 30 that branches from the observation optical system 20 and detects an alignment state in the XYZ directions, and an eye refractive power measurement optical system. 40, a target optical system 50 that presents a target for gazing at the eye E, and the optical axis of each optical system is coupled to the same axis O ₁ immediately before the eye E. The configuration of each optical system will be described below.

  The observation optical system 20 includes illumination light sources 21L, 21R, 22L, and 22R that emit light in the infrared region, a wavelength selection mirror 23, a lens 24, a wavelength selection mirror 25, a light splitting mirror 26, a lens 27, and an observation CCD 28. Has been. Here, the wavelength selection mirror 23 has a characteristic of transmitting the wavelength in the infrared region and reflecting the wavelength in the visible region of the target light source 61 described later. The wavelength selection mirror 25 transmits light in the infrared region wavelength emitted from the illumination light sources 21L, 21R, 22L, and 22R, and reflects light in the infrared region wavelength emitted from the measurement light source 41 described later. It is a characteristic. The observation CCD 28 in this embodiment is assumed to perform progressive (non-interlace) output.

  The alignment optical system 30 includes a lens 31, a cylindrical lens 32, and a two-dimensional position detection element 33, and guides the image of the eye E to be examined divided by the light dividing mirror 26 of the observation optical system 20 to the two-dimensional position detection element 33. . Here, the two-dimensional position detection element 33 is assumed to be of a charge storage type capable of outputting received light information as luminance distribution information.

The eye refractive power measurement optical system 40 includes a measurement light projection system 40t that projects measurement light onto the fundus of the eye E and a fundus reflection light receiving system 40r that receives the reflected light from the fundus of the eye E.
The measurement light projection system 40t is composed of a measurement light source 41, a lens 42, a ring diaphragm 43, a light splitting mirror 44, and a lens 45 that emit wavelengths in the infrared region having different bands from the illumination light sources 21L, 21R, 22L, and 22R. The light from the measurement light source 41 (measurement light) is reflected by the wavelength selection mirror 24 of the observation optical system 20 and guided to the fundus of the eye E to be examined.
The fundus reflection light receiving system 40r includes a lens 45, a light splitting mirror 44 that is also used as a measurement light projection system 40t, a diaphragm 46, a lens 47, and a measurement CCD 48 that can move in the optical axis direction. The measurement light reflected by the fundus of E is guided to the measurement CCD 48.

  The target optical system 50 includes a target light source 51 that emits light including at least wavelengths in the visible region, a target 52 that can move in the optical axis direction, and a lens 53, and the wavelength selection mirror 22 of the observation optical system 40. The visual target image is guided to the eye E to be examined. When the target light source 51 emits light including a wavelength other than the visible region, a filter that prevents the light E having a wavelength outside the visible region from being irradiated to the eye E may be disposed in the target optical system. .

  FIG. 3 shows a block diagram of the apparatus. The control means 70 for controlling the apparatus includes a microprocessor (not shown) and a ROM for storing a program, a memory for holding data, an interface for peripheral devices, and the like, and includes illumination light sources 21L, 21R, 22L, 22R, a measurement light source 41, a target light source 51, a joystick 4 (a position detection element (not shown) provided therein), a measurement switch 5, an operation panel 6, and an observation CCD 28 for the eye E are connected. The measurement CCD 48 is connected to the control circuit 70 via the image processing circuit 72. Further, the CCD motor 81 for driving the measurement CCD 48, the target motor 82 for driving the target 52, the X-axis motor 83 for driving in the left-right direction, the Y-axis motor 84 for driving in the up-down direction, and the driving for the front-rear direction. The Z-axis motor 85 is connected to the control circuit 70 via drive circuits 74 to 78, respectively. In addition to this, the monitor 7 is connected to the control circuit 70 via a combination circuit 73 which is also connected to the graphic display circuit 72 and the aforementioned observation CCD 28.

  The operation of the apparatus having the above configuration will be described. First, the operator aligns the apparatus with respect to the eye E by operating the joystick 4 while confirming the image of the eye E to be examined observed by the observation CCD 28 on the monitor 7. Some recent ophthalmic devices employ a configuration in which an alignment state is automatically detected by providing a means for detecting the alignment state. However, even in these devices, the alignment state cannot be detected. When the automatic alignment setting is canceled, the operator performs alignment while observing the eye E.

  4 and 5 show a flow chart and timing chart of light reception control of the observation CCD 28 and the two-dimensional position detection element 33 provided in the observation optical system 20 and the alignment optical system 30. FIG. The light reception control of the observation CCD 28 and the two-dimensional position detection element 33 is performed based on the frame switching timing of the observation CCD 28. The contents of the control will be described below mainly based on FIG. In the following description, 21L and 21R in FIG. 2 correspond to the illumination light source 1, and 22L and 22R in FIG.

When the control circuit 70 detects an observation screen display signal generated after an initialization process at the time of power-on or by an operation for switching to a state in which measurement is performed, the control circuit 70 starts monitoring the frame switching signal (synchronization signal) of the observation CCD 28. . The control circuit 70, a zero control reference time T _p which is set to use as a reference for the timing of the subsequent control upon detecting a frame switching signal.

The illumination light source is controlled simultaneously with the above-described control reference time T _{p being set} to zero. The illumination light source to be controlled and the control content are selected based on the latest lighting light source information for identifying (specifying) the illumination light source that has been turned on immediately before. The latest lighting light source information is updated every time the illumination light source is turned on. However, since the illumination light source is not turned on when the observation screen display signal is detected, the latest lighting light source information is not set. Therefore, the control content when the latest lighting light source information is not set is set to lighting of one illumination light source (illumination light source 1 in this embodiment). As a result, the latest lighting light source information is set and held in the memory as the illumination light source is turned on. Here, since the illumination light source 1 is turned on, “1” is set as the latest illumination light source information. However, the information is not limited to a numerical value as long as the illuminated illumination light source can be specified. For example, if the eye E is illuminated from the left and right with two illumination light sources, the latest lighting light source information can be set to “L” or “R”.

Charge accumulation of the two-dimensional position detection element 33 is started in accordance with the control of the illumination light source described above. At this time, information on the eye E illuminated by the illumination light source is also received by the observation CCD 28.
FIG. 6 shows a state in which the observation image of the eye E to be received by the observation CCD 28 is displayed on the monitor 7 in a state where the apparatus is aligned with the eye E. Here, the intersection of the vertical and horizontal center lines of the display range of the monitor 7 is set to coincide with the optical axis O ₁ of the optical system shown in FIG.
FIG. 6A shows a state in which the illumination light source 1 and the illumination light source 2 are turned on. Reflected images R _21L and R _21R of the illumination light source 1 and reflected images R _22L and R _22R of the illumination light source 2 are displayed on the eye E. Observed. Note that the reflection image of the illumination light source is indicated by “●” and “◯”, so that it can be identified whether it is caused by the illumination light source 1 or the illumination light source 2 depending on the presence or absence of the internal paint.
6B and 6C are observation images of the eye E in a state where only one of the illumination light source 1 or the illumination light source 2 is turned on. Here, the eye E displayed on the monitor 7 becomes brighter as it is closer to the reflected image of the superimposed illumination light source. For example, in the case of FIG. 6B, the upper left and lower right areas are brighter and the lower left and upper right areas are darker, and in the case of FIG. Therefore, during the period when only one illumination light source is lit and the brightness is non-uniform, the observation information of the eye E is discarded by putting the observation CCD 28 in a charge sweeping state. Thereby, it is possible to prevent the observation image of the eye E to be displayed displayed on the monitor 7 from flickering due to the lighting state of the illumination light source.

When T _p reaches a predetermined time T _sub that is arbitrarily set within a range not exceeding one frame scanning time, the control circuit 70 sweeps out the electric charge accumulated in the two-dimensional position detection element 33 and holds it in the memory as alignment information. . At this time, the latest lighting light source information is associated and used for alignment control described later. At the same time, the control circuit 70 switches the state of the two-dimensional position detection element 33 to charge sweeping and the observation CCD 28 to charge storage. The control circuit 70 controls the illumination light source based on the latest lighting light source information. Here, an illumination light source different from the illumination light source held as the latest lighting light source information is turned on.
Therefore, when the latest lighting light source information is “1” (corresponding to the time when T _{sub of} Frame [i] has elapsed in FIG. 5), the illumination light source 2 is turned on and the illumination light sources 1 and 2 are turned on. The monitor 7 displays an observation image (corresponding to FIG. 6A) of the eye E with uniform brightness on the entire screen. Further, when the illumination light source is turned on, the latest illumination light source information is updated. If the illumination light source 2 is illuminated, the latest illumination light source information is rewritten to “2” and held in the memory. The states of the illumination light source 1 and 2 / observation CCD 28 / two-dimensional position detection element 33 are continuously maintained until the control circuit 70 detects the next frame switching signal from the observation CCD 28.

The control circuit 70 is a T _p to 0 when it detects a new frame switching signal from the observation CCD 28. Further, the control circuit 70 sweeps out the charges accumulated in the observation CCD 28. Here, an observation screen of the eye E is displayed on the monitor 7 based on the electric charges swept from the observation CCD 28.

Thus, the acquisition of the alignment information by the two-dimensional position detection element 33 and the observation information of the eye E to be examined by the observation CCD 28 during one frame scanning time of the observation CCD 28 is completed. However, in order to acquire the difference information from the alignment information by the two-dimensional position detection element 33, two pieces of alignment information acquired in the respective states in which different illumination light sources are turned on are necessary. The illumination light source is controlled so that charges are accumulated in the two-dimensional position detection element 33 in a state where different illumination light sources are turned on. Here, since the illumination light source held as the latest lighting light source information is turned on after the alignment information is acquired by the immediately preceding two-dimensional position detection element 33, the immediately preceding alignment information is held as the latest lighting light source information. It is acquired with the illumination light source not turned on. (At the time of switching between Frame [i] and Frame [i + 1] in FIG. 5, the latest lighting light source information is “2”, and the two-dimensional position detection element 33 turns on the illumination light source 1 within the scanning period of Frame [i]. (Get the information in the state you did)
Accordingly, the illumination light source that is not held as the latest lighting light source information is turned off, and then the processing after paragraph [0030] is performed, so that the alignment information by the two-dimensional position detection element 33 in the continuous frame scanning time is the previous frame scanning time. The observation information of the eye E to be obtained acquired by the observation CCD 28 in a state where any illumination light source is lit is displayed on the monitor 7. .

  By repeating the above paragraphs [0030] to [0033], alignment information in a state where the illumination light sources 1 and 2 are alternately turned on every frame scanning period is acquired from the two-dimensional position detection element 33. By performing a differential process on the two pieces of alignment information acquired during the two-frame scanning period, it is possible to acquire alignment information from which only information on the illumination light source is extracted and perform accurate alignment. Although the procedure to the end is not described in the flow shown in FIG. 4, the procedure is forcibly terminated by the occurrence of interrupt processing such as completion of measurement or switching to a setting change screen inside the apparatus.

  Subsequently, a procedure for detecting the alignment state based on the alignment information described above will be described. FIG. 7 shows a control flow related to alignment.

First, alignment information associated with the latest lighting light source information acquired in the above paragraph [0031] will be described. The observation light beam of the eye E guided to the two-dimensional position detection element 33 is also received by the observation CCD 28. FIG. 8 shows the luminance distribution information of the eye E acquired by the observation CCD 28 when the observation image shown in FIG. 6 is displayed on the monitor 7. FIG. 8A shows the luminance distribution obtained by the lines between XX (horizontal direction) and Y-Y (vertical direction) in the central portion of the observation CCD 28 in the vertical and horizontal directions. It is understood that the eye E has different luminance at each part of the pupil E _p , iris E _i , sclera E _s , and 瞼 E _l . FIG. 8B is acquired by lines between X′-X ′ (horizontal direction) and Y′-Y ′ (vertical direction) including the image of the illumination light source 1 or 2 in the vertical and horizontal directions of the CCD 28 for observation. The luminance distribution is shown. The brightness of the reflected image of the illumination light source 1 or 2 is higher than the brightness of each part of the eye E. This is because the image of the eye E is formed by the light beam emitted from the illumination light source 1 or the illumination light source 2 and back-scattered in the cornea. (The image of the backscattered light has a lower luminance distribution than the virtual image of the light source by specular reflection.) Therefore, it is possible to specify the signal of the image of the illumination light source by comparing the luminance values.

By the way, the luminance distribution information shown in FIG. 8A or FIG. 8B reflects only the luminance acquired in one line in the horizontal (X) direction or vertical (Y) direction of the light receiving region. In order to acquire the position information of the illumination light source reflecting the luminance distribution information of the entire light receiving area, it is necessary to evaluate the luminance distribution information in all lines. However, depending on the specifications of the two-dimensional position detection element, the number of lines may be several hundred, so it takes time to evaluate the luminance distribution information of all the lines and acquire the position information reflecting the entire light receiving area. It will be.
Here, attention is paid to luminance projection data acquired in the horizontal or vertical direction. Luminance projection data is obtained by summing all luminance values existing in one line.
FIG. 9 shows the distribution of the projection data acquired from the information of the observation CCD 28 shown in FIG. According to this, the horizontal position Cx1, Cx2 or the vertical position Cy1, Cy2 of the illumination light source specified in FIG. 9 is between X′-X ′ and Y′-Y ′ in FIG. It is understood that the position of the illumination light source specified from the luminance distribution is reflected. Therefore, the position of the illumination light source may be specified based on the distribution information of the brightness projection data obtained from the alignment information.
9 shows the projection data acquired based on the signal from the observation CCD 28. As described above in the description of the optical system, the two-dimensional position detection element 33 outputs luminance distribution information. Projection data can be obtained. In addition, products that directly output luminance projection data are also provided for two-dimensional position detection elements that output luminance distribution information. By using this product, the process of summing luminance information for each line is omitted. Is also possible.

Here, the arrangement of the two-dimensional position detection elements 33 employed in this embodiment will be described with reference to FIG.
FIG. 10A shows the relationship between the display range of the monitor 7 (in other words, the light receiving area of the observation CCD 28) and the light receiving area of the two-dimensional position detection element 33. FIG. The two-dimensional position detection element 33 is inclined at an angle of 45 ° with respect to the coordinate system of the display range (observation screen) of the monitor 7 and the center of the light receiving area of the two-dimensional position detection element 33 corresponds to (matches) the center O of the display range. ) Is arranged to be. The range displayed on the monitor 7 at the in-focus position of the observation optical system is the horizontal direction Dw and the vertical direction Dh.
FIG. 10B shows the light receiving region of the two-dimensional position detection element 33, which is a square region composed of m columns in the horizontal (PSx) direction and m rows in the vertical (PSy) direction. Column and row numbers start at 0. In addition, the code | symbol with a parenthesis in a figure has shown the number of the column or row which refers to the pixel of the two-dimensional position detection element 33. FIG. Further, the length of one side of the light receiving region of the two-dimensional position detection element 33 is PSL.
Here, since the position information detected by the two-dimensional position detection element 33 is information in a coordinate system that does not correspond to the movement direction of the alignment, it needs to be converted to information in the coordinate system corresponding to the movement direction of the alignment. It becomes.
FIG. 10C shows a point P detected by the two-dimensional position detection element 33 as a coordinate system PS (hereinafter referred to as a coordinate system PS) of the two-dimensional position detection element 33 and a coordinate system D ( Hereinafter, this is indicated by a coordinate system D), and the conversion procedure will be described based on this figure. The reference position PS0 of the coordinate system PS is set to a distance Dx0 from the reference position 0 of the coordinate system D in the horizontal (Dx) direction. First, the position of the point P in the coordinate system PS will be examined. The two-dimensional position detection element 33 detects a point P at a position where the PSx direction is PSx1 and the PSy direction is PSy1. Here, if the length of a line segment connecting the reference position PS0 and the point P of the two-dimensional position detection element 33 is LP and the inclination angle with respect to the PSx direction is θ, the polar coordinates are displayed.
PSx1 = LP · cos θ
PSy1 = LP · sinθ
It becomes. Next, the position of the point P in the coordinate system D is examined. When the position in the Dx direction is represented by polar coordinates with the position in the Dx1 direction and the position in the Dy direction as Dy1,
Dx1-Dx0 = LP · cos (θ + 45 °)
Dy1 = LP · sin (θ + 45 °)
Thus, the relationship between the two coordinate systems is derived by expanding the right side of the above equation based on the addition theorem.
Dx1 = (PSx1-PSy1) / √2 + Dx0
Dy1 = (PSx1 + PSy1) / √2
Thereby, the position information of the coordinate system PS is converted into the position information of the coordinate system D. Here, when the alignment reference AS0 is set at the center of the two-dimensional position detection element 33, the position of AS0 in the coordinate system D is Dx0 in the Dx direction and Dy0 in the Dy direction, and Dy0 is the light receiving area of the two-dimensional position detection element 33. Because it corresponds to half of the diagonal length,
Dy0 = PSL / √2
It becomes. Accordingly, the deviation of the point P with respect to the alignment reference AS0 in the coordinate system D is ΔPx in the Dx direction and ΔPy in the Dy direction.
ΔPx = Dx1-Dx0 = (PSx1-PSy1) / √2
ΔPy = Dy1-Dy0 = (PSx1 + PSy1-PSL) / √2
It becomes. However, the above-described deviation represents a deviation in the two-dimensional position detection element 33, and deviations Δx and Δy between the actual apparatus and the eye to be examined are
Δx = MPA · ΔPx = MPA · (PSx1−PSy1) / √2
Δy = MPA · ΔPy = MPA · (PSx1 + PSy1−PSL) / √2
It is expressed. Here, MPA is the magnification of the alignment optical system, and the vertical display range Dh of the monitor 7 shown in FIG. 10A corresponds to the diagonal of the two-dimensional position detection element 33 at the alignment reference position in the Z direction. If set to
Dh = MPA · √2 · PSL
From the relationship
MPA = Dh / (√2 · PSL)
The difference Δx, Δy between the actual device and the eye to be examined is Δx = Dh · (PSx1−PSy1) / (2 · PSL)
Δy = Dh · (PSx1 + PSy1) / (2 · PSL) −Dh / 2
It becomes.
Since the light receiving area of the two-dimensional position detection element 33 is composed of m rows × m columns of pixels as shown in FIG. 10B, the position information is acquired as the pixel column or row number. . Here, the length of one side of one pixel is PSL / m, and when the above-described PSx1 corresponds to the pixel position of the j-th column (the column number starts with 0),
PSx1 = (PSL / m) · (j + 1/2)
Can be expressed as Accordingly, the alignment shifts Δx and Δy in the coordinate system D are calculated based on the detected position information of the two-dimensional position detection element 33 in the coordinate system PS.

11 shows an observation image of the eye E and the two-dimensional position detection element 33 received by the observation CCD 28 in a state where only one of the illumination light sources 1 or 2 shown in FIG. 6B or 6C is turned on. The distribution information of the projection data of luminance acquired by the above is shown.
The dotted lines in the distribution information of the eye E and the projection data in FIGS. 11A and 11B indicate the information when the disturbance light n exists near the center of the eye E. . When disturbance light is present in this way, the method of comparing the luminance values of single alignment information cannot identify the image of the illumination light source.
However, as described in the paragraph [0034], FIG. 11B is obtained when only the illumination light source 2 is turned on from the luminance distribution information of FIG. 11A obtained when only the illumination light source 1 is turned on. 11) is subtracted for each of the vertical and horizontal directions, the disturbance light n and the information on the eye E are excluded as shown in FIG. 11C, and the reflection images (virtual images) of the illumination light source 1 and the illumination light source 2 by the cornea are excluded. Only position information is extracted. At this time, since the sign of the sign is determined by the relationship between the two alignment information in the difference processing (the drawn side and the drawn side), the latest lighting light source information associated with each alignment information in the paragraph [0031] is subjected to the difference processing. By using in, it becomes possible to specify which illumination light source the information is based on whether the sign is positive or negative. For example, the alignment information associated with “2” as the latest lighting light source information (corresponding to FIG. 11B) corresponds to the alignment information associated with “1” as the latest lighting light source information (corresponding to FIG. 11A). ) Is subtracted, the information based on the illumination light source 1 is extracted as a positive value and the information based on the illumination light source 2 is extracted as a negative value as shown in FIG. In this embodiment, the illumination light sources 21L and 21R corresponding to the illumination light source 1 or the illumination light sources 22L and 22R corresponding to the illumination light source 2 are positioned in the Y direction of the illumination light sources 21L and 21R or the illumination light source 22L in the two-dimensional position detection element 33. , 22R are arranged so that the X-direction positions thereof are the same, the Y-direction position of the reflected image of the illumination light source 1 is extracted only at one point Py3. Similarly, the X-direction position of the reflected image of the illumination light source 2 is Only one point Px3 is extracted.

A procedure for evaluating the alignment state of the apparatus and the eye E in the left / right / up / down / front / back (XYZ) directions based on the alignment information and performing the alignment control so that the eye E is positioned at the reference position of the apparatus will be described. When the difference information of the projection data is acquired from the alignment information, first, the alignment state in the front-rear (Z) direction is evaluated. First, a method for evaluating the alignment state in the front-rear (Z) direction in the present embodiment will be described.
FIG. 12A shows the positional relationship between the cylindrical lens 32 and the two-dimensional position detection element 33 viewed from the direction of the projection lens 31, and the cylindrical axis CyA of the cylindrical lens 32 is Y of the two-dimensional position detection element 33. Arranged to match the direction. FIG. 12B shows the positional relationship of the reflected image of the illumination light source irradiated on the two-dimensional position detection element 33 when the alignment state is appropriate. The reflected images of the illumination light source 1 and the illumination light source 2 are arranged so as to be at least half as long as the light receiving area of the two-dimensional position detection element 33. This arrangement makes it possible to specify the light source based on the detection area when only one reflected image of the illumination light source is detected. (Described later)
FIG. 13 shows the positional relationship between the imaging position (focal point) of the light beam passing through the cylindrical lens 32 and the two-dimensional position detection element 33 and the shape of the detected light beam.
FIG. 13A shows the focal position V _fp (corresponding to the focal point of the imaging lens 31) of the light beam (solid line) passing through the cross section including the optical axis parallel to the cylindrical axis CyA of the cylindrical lens 32 and the cylindrical lens 32. It indicates that the two-dimensional position detecting element 33 between the focal position H _fp of the light beam (dotted line) that transmits the section including the optical axis is disposed in perpendicular to the cylinder axis CyA.
FIG. 13B shows the shape of the light beam observed on the light receiving surface of V _fp and H _fp and the two-dimensional position detection element 33 when the optical system shown in FIG. Is shown. Here, a procedure for evaluating the alignment state in the front-rear (Z) direction by arranging the two-dimensional position detection element 33 as shown in FIG.
FIG. 14 shows the two-dimensional position detection element 33 when the position where the two-dimensional position detection element 33 detects a circular light beam in FIG. 13A is set as the alignment reference (Z = 0) in the front-rear (Z) direction. 2 shows that the light beam detected by the sensor changes with the position of the apparatus and the eye E to be examined. 14A shows a state where the eye E is located at the reference position, FIG. 14B shows a state where the eye E is approaching, and FIG. 14C shows a state where the eye E is separated.
When the subject eye E approaches from the reference position (Z <0), the position where the light beam of the subject eye E forms an image in the alignment optical system 30 moves backward (right in the figure). The image of the light beam perpendicular to the cylinder axis of the cylindrical lens 32 that forms an image at the position _fp gradually approaches the two-dimensional position detection element 33. Then, as shown in FIG. 14B, when the image of the light beam orthogonal to the cylindrical axis of the cylindrical lens 32 is formed on the two-dimensional position detecting element 33, the two-dimensional position detecting element 33 is H _{fp in} FIG. A vertically long luminous flux similar to the surface is detected. Conversely, when the eye E moves away from the reference position (Z> 0), the position at which the light beam of the eye E forms an image moves forward (left in the figure), and thus the light beam detected by the two-dimensional position detection element 33. In FIG. 13A, the image of the light beam parallel to the cylindrical axis of the cylindrical lens 32 that forms an image at the position of V _{fp in} FIG. 13A approaches the two-dimensional position detection element 32. Then, when an image of a light beam parallel to the cylindrical axis of the cylindrical lens 32 is formed on the two-dimensional position detection element 33 as shown in FIG. 14 (c), the two-dimensional position detection element 33 becomes V _{fp in} FIG. 13 (b). A horizontally long light beam similar to the surface is detected.
Accordingly, it is possible to evaluate the perspective of the eye E with respect to the reference position based on the shape of the light beam detected by the two-dimensional position detection element 33. However, when the eye E is closer than FIG. 14B or farther away than FIG. 14C, the light beam received by the two-dimensional position detection element 33 is diffused in the vertical and horizontal directions, and the light quantity is reduced. Cannot be identified. In this case, since the above-mentioned perspective evaluation cannot be performed, it is displayed that the alignment state in the front-rear (Z) direction cannot be detected, and the operator is prompted to perform a manual alignment operation.

FIG. 15 shows how the difference information in FIG. 11C and the shape of the image of the illumination light source detected by the two-dimensional position detection element 33 change for each position in the front-rear (Z) direction. Note that the difference information is simply shown in a bar shape as long as it can be understood about changes in height and width, and similar to the reflected image in FIG. Whether it is information or not.
FIG. 15A shows the shape and difference information when the cylindrical lens 32 is not provided, and FIG. 14B shows the shape and difference information when the cylindrical lens 32 is provided. ing. However, FIG. 15A shows a case where the two-dimensional position detection element 33 is disposed at the focal position of the imaging lens 31 (corresponding to the position of V _fp ).
When the eye to be examined is present at the reference position (Z = 0), the illumination light source image formed on the light receiving surface of the two-dimensional position detection element 33 is circular regardless of the presence or absence of the cylindrical lens 32, and FIG. ) Is obtained. When the eye to be examined is far from the reference position (Z> 0), if the cylindrical lens 32 is not provided, the shape is circular as in the case of Z = 0, but the imaging position of the light beam is V _fp ′. Therefore, the area of the light beam received by the two-dimensional position detection element 33 is expanded, and the amount of received light per area is reduced. Also in FIG. 15B, since the image of the illumination light source formed on the light receiving surface of the two-dimensional position detection element 33 extends in the X direction, the projection data in the distribution in the X direction becomes low, but the light flux in the Y direction converges. The projection data in the distribution in the Y direction is approximately the same size as the reference position. On the contrary, when the eye to be examined is closer than the reference position (Z <0), the luminous flux of the image of the illumination light source received by the two-dimensional position detection element 33 extends in the Y direction, so that the projection data in the Y direction distribution is low. However, the projection data in the distribution in the X direction is almost the same size as the reference position.
Here, when the cylindrical lens 32 is not disposed, the difference signal is almost the same as when the eye E is away from the reference position (Z> 0), and thus is acquired by the two-dimensional position detection element 33. The distance of the eye to be examined cannot be identified based on the difference information. However, by adopting a configuration in which the light beam transmitted through the cylindrical lens 32 is received by the two-dimensional position detecting element 33, at least in the X direction or the Y direction within the range having both ends in FIG. 14 (b) and FIG. 14 (c). On the other hand, projection data having a size equal to or larger than the reference position is acquired.
Therefore, the positional relationship in the front-rear (Z) direction is grasped by evaluating whether or not the size of the projection data in the X direction and the Y direction is equal to or larger than a predetermined value (broken line shown in the difference information in FIG. 15). . Note that the projection data based on the illumination light source 2 in the X direction distribution (no filling) and the projection data based on the illumination light source 1 in the Y direction (filled) are half-value because the information of the two illumination light sources overlaps. Note that it is necessary to make the above assessment based on this. For example, when only the projection data in the distribution in the X direction of the difference information, such as Z <0, is larger than a predetermined size, it is grasped that the eye E is located closer to the reference position. The control circuit 70 performs drive control of the Z-axis drive motor 85 via the drive circuit 78 so that the eye part 3 is separated from the eye E so that the eye part 3 is separated from the eye E. Then, by repeating the evaluation of the size of the projection data of the difference information and the control of the Z-axis drive motor 85 based on the evaluation, the projection data in the distribution in the Y direction in the difference information as the optometry unit 3 moves away from the eye E is also obtained. growing. When only the projection data in the distribution in the Y direction is greater than or equal to a predetermined value, drive control for causing the optometry unit 3 to approach the eye E to be examined may be performed.
Whether or not the alignment in the Z direction is in an appropriate state (Z = 0) is determined based on the size (height) in the distribution in the X direction and the distribution in the Y direction of either the positive or negative projection data of the difference information. This is done by comparison. When the reflected light beam of the illumination light source received by the two-dimensional position detection element 33 is circular, the size (height) of all projection data related to the reflected image of the illumination light source extracted in the X-direction distribution of the difference information. ) And information obtained by integrating the sizes (heights) of all projection data related to the reflected image of the illumination light source extracted in the Y-direction distribution are substantially the same. Therefore, if the difference between the information obtained by integrating the sizes (heights) of all the projection data extracted in the distribution in the X direction and the information obtained by integrating the sizes (heights) of the projection data in the Y direction is zero, It can be determined that the reference position is in the (Z) direction. For example, when Z = 0 in FIG. 15B, there is projection data with a positive sign and projection data with a negative sign in the difference information, and information of two illumination light sources is reflected in each projection data. ing. When the projection data is limited to positive projection data, there are two projection data in the X-direction distribution and one projection data in the Y-direction distribution. Here, since the projection data existing in the distribution in the Y direction overlaps the information of the two illumination light sources, the projection data is almost equal to the height obtained by integrating the two projection data recognized in the distribution in the X direction. The difference between the projection data existing in the direction distribution and the projection data existing in the Y direction distribution is zero. FIG. 15 shows an example in which all reflected images related to the illumination light source 1 and the illumination light source 2 are detected. However, any one of the reflected images of the illumination light source 1 or the illumination light source 2 is a two-dimensional position detection element 33. It is possible to evaluate the alignment state in the front-rear (Z) direction.
FIG. 16 shows that difference information acquired by the two-dimensional position detection element 33 varies depending on the alignment state in the front-rear (Z) direction in a state where only one reflected image of the illumination light source is detected due to the deviation in the vertical and horizontal (XY) directions. It shows what to do. The reflected image of the illumination light source emitted toward the eye E is confirmed in the upper right direction of the monitor 7 when the eye E is located near the upper right side of the monitor 7 as shown in FIG. The Here, since the display range of the monitor 7 and the detection range of the two-dimensional position detection element 33 have the relationship shown in FIG. 10A, only the reflected image of the illumination light source 22L is two-dimensional in the example of FIG. It is detected by the position detection element 33. FIG. 16B shows difference information acquired by the two-dimensional position detection element 33 in each state shown in FIGS. 14A to 14C. In the case of Z = 0 in FIG. 16B, since the projection data having a negative sign has the same size (height) in the X direction distribution and the Y direction distribution, the difference is almost zero.

If the alignment in the front-rear (Z) direction is in an appropriate state, the alignment state in the left-right and up-down (XY) directions and drive control are subsequently performed.
FIG. 17 shows a state in which the difference information acquired by the two-dimensional position detection element 33 changes depending on the degree of deviation in the left / right / up / down (XY) direction. FIGS. 17A to 17C show difference information when the number of reflected images of the illumination light source detected by the two-dimensional position detection element 33 changes.
First, as shown in FIG. 17A, when the alignment state in the left-right and up-down (XY) directions is greatly deviated from the appropriate position, the two-dimensional position detection element 33 detects only one reflected image of the illumination light source. By moving the intermediate point MP of all illumination light sources to the center of the two-dimensional position detection element 33, the alignment state becomes appropriate, but in the state of FIG. 17A, MP is detected by the two-dimensional position detection element 33. Since it is out of range, the amount of deviation from an appropriate alignment state cannot be recognized. However, in the example of FIG. 17A, the position of the detected reflected image R _21R of the illumination light source is + ΔPSxPP, PSy in the PSx direction with respect to the reference position (intersection of CL _X and CL _Y ) of the two-dimensional position detection element 33. It can be understood that the direction is shifted by -ΔPSyPP. Here, by performing drive control so that the reflected image R _21R of the illumination light source moves in a direction to eliminate the above-described deviation, as shown in FIG. 17B, within the light receiving region of the two-dimensional position detection element 33. An intermediate point MP is derived. When the intermediate point MP is guided into the light receiving region of the two-dimensional position detection element 33, at least one reflected image of the illumination light source 2 is also guided into the light receiving region in addition to the illumination light source 21R.
Accordingly, since the difference information includes two pieces of information from the illumination light source 1 and the illumination light source 2, the reference position of the two-dimensional position detection element 33 and the positional relationship of the MP can be grasped. Accordingly, since the movement amounts ΔPSxMP and ΔPSyMP necessary for guiding the intermediate point BP to the reference position of the two-dimensional position detection element 33 can be calculated, drive control for moving the optometry unit 3 can be performed.
By repeating the acquisition of the difference information and the drive control described above, the shift between the intermediate point BP and the reference position of the two-dimensional position detection element 33 is gradually eliminated, and finally the intermediate point BP as shown in FIG. Is close to the reference position (the center of the light receiving area) of the two-dimensional position detection element 33, so if the deviation between the intermediate point BP and the two-dimensional position detection element 33 is less than or equal to a predetermined amount, the horizontal and vertical directions Is determined to be appropriate, and the alignment drive of the optometry unit 3 is stopped. Here, by outputting a signal notifying that the alignment is in an appropriate state, it is possible to notify the operator that the measurement / inspection has been performed and to automatically perform the measurement / inspection. It becomes possible.

Subsequently, the measurement of the eye refractive power assumed by the present embodiment for the measurement / inspection will be described. When grasping the completion of the alignment, the operator operates the measurement switch 5. When the control circuit 70 connected to the measurement switch 5 detects that the measurement switch 5 is operated, the measurement light source 41 of the measurement light projection system 40t of the eye refractive power measurement optical system 40 and the target of the target optical system 50 are detected. The light source 51 is turned on. The measurement light is irradiated to the fundus of the eye E as a ring-shaped light beam via the measurement light projection system 40t. At the same time, the light of the target 52 irradiated to the target light source 51 is guided to the fundus of the eye E via the target optical system 50, the observation optical system 20, and the eye refractive power measurement optical system 40, and during the measurement. A target to be a fixation target is presented to the eye E. Further, during the measurement, the control circuit 70 moves the visual target 52 in the axial direction by controlling the visual target drive motor 82 via the drive circuit F75 in order to cause the eye E to be clouded.
The measurement light applied to the eye E is reflected on the fundus and guided to the measurement CCD 48 via the fundus reflection light receiving system 40r. Since the focus position of the fundus reflection light fluctuates due to the eye refractive power of the eye E, the control circuit 70 moves the measurement CCD drive motor 81 in the axial direction via the drive circuit C74, and the fundus is in the focused state. The reflected light image can be detected. The ring image (fundus reflection light) detected by the measurement CCD 48 in this way changes in size according to the eye refractive power of the eye E, and the eye refraction is detected by detecting the size of the ring image. Power is required. The relationship between the size of the ring image detected by the measurement CCD 48 and the eye refractive power is described in Japanese Patent Application Laid-Open No. 2003-102687 by the applicant of the present application and is not related to the present invention, so that the description thereof is omitted. The obtained eye refractive power is displayed on the monitor 7 of the main body 10 by the control circuit 70 via the graphic display circuit 72 and the synthesis circuit 73.

  The embodiment of the present invention has been described in detail above, but is not limited to any specific description in the embodiment, and various modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention, Needless to say, embodiments with modifications, improvements and the like are also included in the scope of the present invention.

  In the above-described embodiment, the illumination light source 1 and the illumination light source 2 are each composed of two light sources. However, even when the illumination light source 1 and the illumination light source 2 are each one as shown in FIG. It is possible to grasp the deviation in the up / down and front / rear (XYZ) directions and to perform alignment driving to the reference position. For the front-rear (Z) direction, drive control may be performed so that the sizes (heights) of the projection data in the PSx direction and the PSy direction are the same as described in paragraph [0041]. In the left / right / front / rear (XY) directions, the drive control is performed by changing the target guided to the reference position of the two-dimensional position detection element 33 according to the number of reflected images of the illumination light source detected in the same manner as in the paragraph [0042]. Here, when the number of detected reflected images is one, the detected reflected images are targeted, and when the number of detected reflected images is two, the intermediate point between the two reflected images may be targeted.

In the above-described embodiment, the positional relationship in the front-rear (Z) direction can be detected by disposing the cylindrical lens 32 in the alignment optical system 30. However, the positional relationship in the front-rear (Z) direction is determined from an accuracy problem. In the case where a configuration for detection is provided separately, the cylindrical lens 32 may be omitted, and the two-dimensional position detection element 33 may detect only the left, right, up and down (XY) directions. Here, the observation CCD 28 is of an interline type, and the ODD field scanning time is set as T _sub for controlling the lighting timing of the illumination light source as shown in FIG. The observation information of the eye to be examined when only the light is turned on is acquired as the output of the ODD field, and the alignment in the left / right / up / down (XY) direction based on the difference between the projection data of the output signals of the ODD field in two consecutive frames Since the state can be detected, the two-dimensional position detection element 33 (alignment optical system 30) can be omitted. However, since the ODD field in which only one illumination light source is turned on is reflected, the flicker of the observation image displayed on the monitor 7 cannot be completely eliminated unlike the case of using the progressive CCD.

  As described above, in the ophthalmologic apparatus according to the present invention, the lighting control of a plurality of light sources that illuminate the subject's eye and the element capable of detecting the two-dimensional position of the reflected image of the light source reflected by the subject's eye By synchronizing the drive control, it is possible to extract only the position information of the reflected image of the light source from the output signal of the element capable of detecting the two-dimensional position described above, thereby avoiding malfunction caused by ambient light or the like. An appropriate alignment state can be acquired.

7 Monitor 20 Observation optical system 21L, 21R, 22L, 22R Illumination light source 28 CCD for observation
DESCRIPTION OF SYMBOLS 30 Alignment optical system 32 Cylindrical lens 33 Two-dimensional position detection element 40 Eye refractive power measurement optical system 50 Index optical system 70 Control circuit

Claims (4)

An optometry unit incorporating an optometry optical system for examining or measuring the eye;
Moving means for moving the optometry unit three-dimensionally;
A plurality of illumination light sources for illuminating the eye to be examined;
An observation optical system for receiving and observing an image of the eye to be examined illuminated by the plurality of illumination light sources on an imaging device;
Display means for displaying the eye image received by the imaging device;
Light source lighting control means for blinking the plurality of illumination light sources in synchronization with a control signal of the image sensor;
Alignment in which at least a part for obtaining an alignment state between the optometry unit and the eye to be detected is detected by a two-dimensional position detection element superimposed on the eye image to be examined and used as the observation optical system. State acquisition means,
In an ophthalmologic apparatus that moves the optometry unit based on the alignment state detected by the alignment state acquisition means,
The light source lighting control unit switches between a first state in which half of the plurality of illumination light sources are lit and a second state in which all of the illumination light sources are lit within the imaging cycle of the imaging element, and when the transition to the next imaging cycle is performed. Control is performed so that turning on and off in the state 1 is reversed, and the alignment state acquisition means compares the two signals output from the two-dimensional position detection element in synchronization with the control signal of the light source lighting control means An ophthalmologic apparatus characterized by acquiring an alignment state based on information. 2. The ophthalmologic apparatus according to claim 1 , wherein switching between the first state and the second state is performed in synchronization with field switching of the image sensor or electronic shutter timing. The plurality of illumination light sources are arranged at positions that are point-symmetric with respect to the optical axis of the optometry optical system, and the two-dimensional position detection element includes a light source that is turned on and a light source that is turned off in the first state. The ophthalmic apparatus according to claim 1 , wherein the ophthalmologic apparatus is disposed so as to be inclined at 45 ° with respect to a straight line connecting the two . The imaging device is an ophthalmic apparatus according to any one of claims 1 to 3, characterized in that it is also used as the two-dimensional position detecting element.

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