JPH11206709A - Objective type eye refractive power measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe the anterior part of an eye to be examined in colors. SOLUTION: This eye refractive power measurement device objectively measures the refractive power of the eye E to be examined. In this case, it is provided with a white LED 30 (30a-30h) for projecting visible light to the eye E to be examined, an observation optical system 3 for leading the visible light projected by the white LED 30 (30a-30h) and reflected at the eye E to be examined, a color CCD camera 34 for picking up the image of the visible light led by the observation optical system 3 and a color monitor for displaying the image picked up by the color CCD camera 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective eye refractive power measuring apparatus provided with objective measuring means for objectively measuring the refractive power of an optical system to be inspected, and particularly for observing an anterior eye. The present invention relates to an objective eye-refractive-power measuring device that can perform the measurement.

[0002]

2. Description of the Related Art Conventionally, an objective measurement apparatus for objectively measuring the refractive power of an eye to be examined has been widely used. Among such objective eye-refractive-power measuring devices, near-infrared light is projected onto the anterior segment of the subject's eye, and near-infrared rays reflected by the anterior segment are imaged by a monochrome CCD camera or the like, and the monochrome There has been proposed an apparatus that can observe an alignment state of the apparatus with respect to an eye to be examined by displaying the image on a monitor.

[0003] The reason that near infrared rays are used as a light source for observation in such a measuring device is that when visible light is projected, the subject's eye is miotically mimicked by the visible light, which may hinder measurement. Because there is.

[0004]

However, in such a conventional objective eye refractive power measuring device, a near-infrared light source is used as a light source for observing the state of the eye to be inspected. Even if the state of the eye to be inspected is displayed, the image becomes a black and white image, so that there is a problem that the actual color change is difficult to see and the state of the eye to be inspected cannot be observed in detail.

The present invention has been made in view of the above-mentioned problems in the conventional objective eye refractive power measuring apparatus, and is an objective eye capable of observing the state of the anterior segment with visible light. It is an object of the present invention to provide a refractive power measuring device.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems in the conventional objective type eye refractive power measuring apparatus, the present invention according to claim 1 objectively measures the refractive power of the eye to be examined. In an objective eye refractometer, a visible light source for projecting visible light to the eye to be examined, an observation optical system for guiding visible light projected from the visible light source and reflected by the eye to be examined, and It is characterized by comprising imaging means for imaging visible light guided by the observation optical system, and display means for displaying an image imaged by the imaging means.

[0007] The present invention described in claim 2 provides the present invention.
In the present invention, the visible light source is a white LED.

[0008] The present invention according to claim 3 provides the present invention.
Alternatively, in the present invention according to claim 2, a plurality of the visible light sources are provided, and the plurality of visible light sources are arranged at positions where visible light can be projected to the subject's eye at different angles from each other. ing.

The present invention according to claim 4 provides the present invention according to claim 1.
According to the present invention, the image pickup means is a color image pickup device.

[0010] The present invention described in claim 5 provides the present invention in claim 1.
The present invention according to any one of claims 4 to 6, further comprising a light amount adjusting unit for arbitrarily adjusting the amount of visible light projected from the visible light source.

[0011]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing the optical configuration of the objective eye refractive power measuring device from the side, FIG. 2 is an enlarged view around the measurement window viewed from the subject, and FIG. 3 is a screen displayed on the color monitor 4. FIG. 4 is a block diagram showing an electrical configuration of an objective eye refractive power measuring device.

First, the configuration of the objective eye refractive power measuring device will be described, and then the measuring procedure by the objective eye refractive power measuring device will be described. As shown in FIG. 1, the objective eye refractive power measuring device includes a measuring unit 1 serving as an objective measuring means for objectively measuring the refractive power of the eye E, and fixing the eye E in a predetermined direction. A fixation optical system 2 for visualizing, a white LED 30 and an infrared light source 31 which are light sources for projecting observation light to the eye E to observe the state of the anterior segment of the eye E
An observation optical system 3 for guiding the light projected by the visible light source 30 or the infrared light source 31 and reflected by the eye E through a common path, and a light guided by the observation optical system 3. A color CCD camera 34 serving as an image pickup means for picking up an image, a color monitor 4 serving as a display means for displaying an image picked up by the color CCD camera 34, these measuring unit 1, fixation optical system 2, and observation optics FIG. 4 for controlling the system 3 etc.
And a control unit 5 shown in FIG.

The measurement section 1 and the fixation optical system 2 are based on the same principle and configuration as those of the conventional objective measurement apparatus, and the details are omitted, and only the outline is described. Measuring unit 1
Projects the measuring light onto the eye E and receives the measuring light reflected by the eye E. Specifically, as shown in FIG. 1, the measuring unit 1 includes an infrared light source 10, lenses 11, 12,
The chopper 13 is configured to include a chopper 13, a half mirror 14, a stop 15, and a light receiver 16. The measurement light emitted from the infrared light source 10 is scanned by the chopper 13 through the lens 11, and the scanned measurement light is half The light is guided to the eye E via the mirror 14, and the measurement light reflected by the fundus of the eye E and the measurement light reflected by the cornea are received by the light receiver 16 via the half mirror 14, the lens 12 and the aperture 15. Receive light.

The light receiver 16 has two pairs of photoelectric conversion elements (not shown) for receiving the measurement light reflected from the fundus of the eye E, and a four-part split for receiving the measurement light reflected from the cornea. A light receiving element is arranged. When the measurement light is received by the photoelectric conversion element, a signal is output from the photoelectric conversion element to the control unit 5. In the control unit 5, the measurement light received by the pair of photoelectric conversion elements and the other pair of the measurement light are output. A measurement value is calculated based on a phase difference from the measurement light received by the photoelectric conversion element.

In the four-divided light receiving element, four elements are arranged at equal positions in the upper, lower, left and right directions around the optical axis. When each element receives the measurement light, a signal is output to the controller 5. The control unit 5 determines whether or not the alignment state of the subject's eye E with respect to the objective measurement device is appropriate based on the difference in the amount of measurement light received by each element.

The fixation optical system 2 is composed of a visible light source 20 for fixation, a fixation target 21, a lens 22, and half mirrors 23 and 24.
The fixation light transmitted through the first and second mirrors 21 and 2
The eye E is projected onto the eye E via the lenses 3 and 24, and fixation of the eye E is performed by showing fixation light to the subject. In the case of observing visible light here, since the subject is illuminated with visible light, the subject's eye may be miotic, so that the fixation target 21 is difficult to see and the line of sight of the subject is difficult to determine. Prone. For this reason, stable observation becomes difficult. Therefore, it is desirable to change the brightness of the visible light source 20 illuminating the fixation target in conjunction with the selection of the visible light LED and the change in the brightness. Therefore, the microprocessor 58
In the case of color observation, the brightness of the fixation target 21 is set according to the input of the white LED operation panel 57, and the brightness of the visible light source 20 is adjusted through a fixation target driving circuit (not shown). You may. The microprocessor 58
Adjusts the brightness of the visible light source 20 so that the subject's eye is sufficiently mydriatic during refraction measurement of infrared observation. Also. If a white LED is used as the visible light source 20 for illuminating the fixation target, it is convenient to control the change in brightness and the change in color temperature is small.

Here, the present apparatus is used for color observation for observing the anterior eye of the eye E to be examined with visible light, and for observing the anterior eye of the eye E with infrared light as in the prior art. It is possible to selectively perform both the infrared observation and the white LED 30 described above as a visible light source for color observation, and the red LED described above as an infrared light source for infrared observation. An outer LED 31 is provided.

As shown in FIG. 2, eight white LEDs 30 are provided around the measurement window 6 provided on the surface of the apparatus housing on the side of the subject, and the white LEDs 30 are mutually disposed with respect to the subject's eye E. They are arranged at positions that project visible light at different angles. In the present embodiment, the white LEDs 30a to 30d belonging to the first group, which are L1 away from the center position of the measurement window 6 (the optical axis position of the measurement light by the measurement unit 1), and the second LEDs, which are L2 away from the center position of the measurement window 6, White LED 30e belonging to the second group
30h are arranged. And as shown in FIG.
The visible light emitted from the white LEDs 30a to 30d belonging to the first group is at an angle α1 to the eye E, and the visible light emitted from the white LEDs 30e to 30h belonging to the second group is to the eye E. Incident at an angle α2. In the apparatus according to the present embodiment, by projecting visible light to the eye E at different angles in this way, it becomes possible to observe the miotic state of the eye E to be described later.

As the white LED 30, NSPW310AS manufactured by Nichia Corporation can be used. This white LED is different from halogen lamps and tungsten lamps commonly used in optometers,
When the brightness of the light source is changed by the current, the change in the color temperature is extremely small. Therefore, it is possible to easily obtain illumination light having a stable color balance, and it is optimal as a light source for video shooting.

Further, such a white LED has a high response speed to lighting and extinguishing, and also has a small calorific value at the time of lighting, so that the subject does not feel hot due to the heat generated by the lighting of the white LED. Since the drying of the eye E, which causes blinking of the subject, can be suppressed, the eye E can be stably observed. Furthermore, since the size is the same as that of a normal LED and small, a plurality of LEDs can be installed in the apparatus without having to consider the installation position.

On the other hand, the infrared LEDs 31 project near-infrared light in the same manner as in the prior art, and are arranged one on each side of the measurement window 6 as shown in FIG.

The observation optical system 3 includes visible light and infrared LEDs 3 projected by the white LED 30 and reflected by the eye E.
Infrared light projected at 1 and reflected by the anterior segment of the eye E to be examined (hereinafter, visible light and infrared light are simply referred to as “observation light” as necessary) is guided through a common path. Total reflection mirror 32, filter switch 33, and color CCD camera 3
4 and a lens 35 and a variable stop 36.

The observation light reflected by the anterior segment of the eye E is
The light is reflected by the half mirror 24 of the fixation optical system 2, passes through the half mirror 23 of the fixation optical system 2, is further reflected by the total reflection mirror 32 of the observation optical system 3, and has a lens 35, a variable stop 36, and a filter switch. It reaches a color CCD camera 34 as an image pickup means via the device 33. The observation light reaching the color CCD camera 34 is subjected to predetermined processing by the control unit 5, and the control unit 5 outputs an image of the anterior eye part to the color monitor 4 shown in FIGS.

Here, the filter switching unit 33 includes an infrared cut filter 37 and a dummy glass 38, and places either the infrared cut filter 37 or the dummy glass 38 on the optical axis of the observation optical system 3. They can be arranged interchangeably. The reason why the infrared cut filter 37 is arranged by the filter switching device 33 is as follows.
First, a semiconductor imaging device used in a color CCD camera or the like generally has high sensitivity in the near infrared region. Therefore, if used for color imaging as it is, an optical signal in the near-infrared region results in an image with poor color balance. For this reason, an infrared cut filter is generally inserted so as to have sensitivity only to visible light.
On the other hand, if the infrared cut filter 37 is always arranged on the optical axis of the observation optical system 3, the infrared light is blocked by the infrared cut filter 37. The anterior eye image does not reach the barrel CCD camera 34. Therefore, it is necessary to remove the infrared cut filter 37 from the optical axis of the observation optical system 3 during observation with an infrared light source. Therefore, in the present embodiment, the infrared cut filter 37 normally provided in the color CCD camera 34 is disposed outside the CCD camera 34 by the filter switch 33 so that the infrared cut filter 37 can be removed from the optical axis at any time. is there.

The reason why the dummy glass 38 is arranged by the filter switch 33 is as follows. That is, if the infrared cut filter 37 is simply removed from the optical axis of the observation optical system 3 by the filter switch 33, the wavelength of the near infrared light (750 nm to 2500 nm) and the wavelength of the visible light (550 nm)
nm) and the influence of the refractive index of the infrared cut filter 37, the image input to the CCD camera 34 is out of focus. Therefore, in the present embodiment, the dummy glass 38 made of a predetermined material and a predetermined thickness in consideration of the difference between the near-infrared wavelength and the visible light wavelength is used. That is, when performing observation using a near-infrared light source, the dummy glass 38 is disposed on the optical axis of the observation optical system 3 in place of the infrared cut filter 37 to eliminate the focus shift. As described above, the infrared cut filter 37 and the dummy glass 38 are provided in the filter switch 33 so that the infrared cut filter 37 and the dummy glass 38 can be exchanged on the optical axis of the observation optical system 3. I have.

The variable stop 36 provided between the filter switch 33 and the total reflection mirror 32 is a color CCD.
When the exposure of the camera 34 becomes excessive or insufficient, the amount of light received by the color CCD camera 34 is adjusted so that the anterior eye part can be observed with an appropriate camera exposure. The color monitor 4 displays an image captured by the color CCD camera 34 so that the image can be observed.

Next, the control section 5 shown in FIG. 4 will be described. The control unit 5 is configured by an electric circuit mainly including a microprocessor, and as shown in FIG.
A white LED control circuit 50 serving as a light amount adjusting means;
Infrared LED control circuit 51 for controlling turning off and on of D31, aperture control circuit 5 for controlling variable aperture 36 of observation optical system 3
2. A filter switching drive circuit 53 for controlling the filter switch 33 of the observation optical system 3, an image correction circuit 54 for correcting an image input to the color CCD camera 34, and a display for outputting and displaying images and characters on the color monitor 4. A circuit 55, a mode changeover switch 56 for switching an observation mode, a white LED to be turned on, and a white light L for instructing a light amount thereof
ED operation panel 57 and these white LED control circuits 5
0, infrared LED control circuit 51, aperture control circuit 52, filter switching drive circuit 53, image correction circuit 54, display circuit 5
5. A microprocessor 58 for controlling the mode changeover switch 56 and the white LED operation panel 57 is provided. The operation of each of these circuits will be described in an observation procedure described later.

Next, the procedure of observing the anterior segment of the eye E using the objective eye refractive power measuring apparatus according to the present embodiment will be described. Observation of the anterior segment is broadly divided into color observation and infrared observation as described above, and the examiner first selects one of the observations with the mode switch 56. When the examiner selects the color observation mode with the mode changeover switch 56, the signal is input to the microprocessor 58, and the microprocessor 58 sends a lighting signal to the white LED control circuit 50, a light-off signal to the infrared LED control circuit 51, Infrared cut filter 3 in filter switching drive circuit 53
7 are output on the optical axis.

The white LED control circuit 50 that has received the lighting signal turns on the white LED 30. At this time, the white LED control circuit 50 as the light amount adjusting means makes the white LED 30 a standard luminous intensity for observing the anterior segment by applying a predetermined amount of current to the white LED 30. The infrared LED control circuit 51 that has received the light-off signal turns off the infrared LED 31. Further, a filter switching drive circuit 53 which has received a signal for arranging the infrared cut filter 37 on the optical axis.
Accordingly, the filter switch 33 of the observation optical system 3 is driven, and the infrared cut filter 37 is arranged on the optical axis of the observation optical system 3.

The observation light emitted from the white LED 30 and reflected by the anterior segment of the subject's eye E is input to the color CCD camera 34 by the above operation, and the observation light is input to the display circuit 55 of the control unit 5. , The color image of the anterior segment is output to the color monitor 4, and the color image of the anterior segment is displayed on the color monitor 4.

Here, the examiner operates a white LED operation panel 57 (not shown) provided on the apparatus, whereby
The position of the white LED 30 to be turned on and the amount of light of the white LED 30 to be turned on can be adjusted. When the examiner operates the white LED operation panel 57, a signal indicating the position and the light amount of the white LED 30 according to the operation content is input to the white LED control circuit 50 via the microprocessor 58, and the white LED control circuit 50 White L to light
A predetermined white LE based on a signal regarding the position of the ED 30
White LED to turn on or off D30 and to turn on again
The luminous intensity of the white LED 30 is changed by increasing or decreasing the current flowing through the white LED 30 based on the signal related to the light amount of the white LED 30. By doing so, it becomes possible to observe the miotic state of the eye E when the position and the light amount of the visible light source are changed. In other words, the glare perceived by the subject differs depending on the position and the amount of light of the visible light source, and the size of the pupil changes accordingly. The state of the iris of the subject's eye E can be observed.

The aperture control circuit 52 of the control unit 5 detects whether the exposure of the CCD camera 34 is excessive or insufficient according to the change in the amount of light at this time. By driving the aperture 36, the color CCD camera 3
Set the exposure of 4 to an appropriate value.

Next, when the examiner selects the infrared observation mode with the mode changeover switch 56, the signal is input to the microprocessor 58, and the microprocessor 58
Therefore, the white LED control circuit 50 sends a light-off signal, infrared LE
The D control circuit 51 includes a lighting signal, a filter switching drive circuit 5,
A signal for arranging the dummy glass 38 on the optical axis is sent to 3.

The infrared LED control circuit 51 which has received the lighting signal turns on the infrared LED 31, and the white LED control circuit 50 which has received the light-off signal turns off the white LED 30 which has been lit in the above-described color observation. Further, the filter switching drive circuit 53 which has received the signal for arranging the dummy glass 38 on the optical axis drives the filter switch 33 of the observation optical system 3 and arranges it on the optical axis of the observation optical system 3 in the above-described color observation. A dummy glass 38 is arranged on the optical axis of the observation optical system 3 in place of the infrared cut filter 37 thus obtained.

The observation light emitted from the white LED 30 by the above operation and reflected by the anterior segment of the eye E to be inspected is input to the color CCD camera 34, and the display circuit 55 of the control unit 5 displays the observation light on the color monitor 4 of the apparatus. The image is displayed, and it is possible to observe the anterior eye part or observe the alignment state for measuring the refractive power.

Here, when a monochrome image is simply displayed on a normal color type monitor, only an unnatural image is displayed. Therefore, in this embodiment, as shown in FIG. 4, the output from the color CCD camera 34 is output to the display circuit 55 via the image correction circuit 54. At the time of infrared observation, a control signal is output from the microprocessor 58 to the image correction circuit 54, and correction is performed so as to eliminate unnaturalness when displaying near infrared light on the color monitor 4.

After performing the infrared observation as described above, when the refractive power of the eye E is measured by the same procedure as the conventional one,
As shown in FIG. 3, the value obtained by the measurement is
(The value obtained by the measurement is indicated by reference numeral 4a). Here, in this embodiment, since the color monitor 4 is used as the display means,
The value 4a obtained by the measurement is displayed in a predetermined color different from other display contents, which makes it easier for the examiner to identify. It is also possible to display the value 4a obtained by the measurement in different colors depending on whether the value is normal or abnormal, thereby preventing an overlook of an abnormal value at the time of mass screening such as at a mass screening. it can. In addition, not only the value selected by the measurement but also the abnormality of the device, the state of the battery, and the like may be displayed in color.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea. Therefore, these different modes will be described below.

First, the visible light source is not limited to a white LED, and another visible light source may be used. Further, the number, arrangement position, and projection angle of the white LEDs 30 are not limited to those shown in FIG. 2, but can be provided in any number, arrangement position, and projection angle. In addition, as for the configuration and arrangement of the observation optical system, any known ones may be applied. The color CCD camera may be any color imaging device such as a color solid-state imaging device or a color semiconductor imaging device.

[0040]

As described above, according to the first and fourth aspects of the present invention, a visible light source for projecting visible light to an eye to be inspected, and a visible light projected from the visible light source and reflected by the eye to be inspected. An observation optical system for guiding the image, an imaging unit for imaging the visible light guided by the observation optical system, and a display unit for displaying an image taken by the imaging unit. , The anterior segment of the subject's eye can be observed in color,
It is possible to obtain color information that has been missing in the conventional infrared observation, and also to easily observe the subject's eye in the miotic state.

Further, according to the present invention, since the visible light source is a white LED, illumination light having a stable color balance can be supplied. In addition, since the calorific value can be reduced and the drying of the subject's eye can be suppressed, there is also an effect that a stable observation of the subject's eye can be performed,
Further, since the visible light source can be made smaller, a plurality of visible light sources can be installed in the apparatus without having to consider the installation position of the visible light source.

Further, the present invention according to claims 3 and 5 is characterized in that a plurality of visible light sources are provided, and the plurality of visible light sources are arranged at positions where visible light can be projected at different angles to the subject's eye. Since the angle at which visible light is incident on the subject's eye and the amount of light can be changed, it is possible to measure not only the anterior segment but also the speed of dark adaptation and light adaptation,
It is also possible to observe the state of the iris of the subject's eye in the state of miosis.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an optical configuration of an objective eye refractive power measuring device viewed from a side.

FIG. 2 is an enlarged view of the vicinity of a measurement window viewed from a subject.

FIG. 3 is a diagram illustrating a screen displayed on a color monitor.

FIG. 4 is a block diagram showing an electrical configuration of an objective eye refractive power measuring device.

[Explanation of symbols]

 Reference Signs List 1 measurement unit 2 fixation optical system 3 observation optical system 4 color monitor 5 control unit 30 white LED 31 infrared LED 33 filter switch 34 color CCD camera 50 white LED control circuit 51 infrared LED control circuit 52 aperture control circuit 53 filter Switching drive circuit 54 Image correction circuit 55 Display circuit

Claims (5)

[Claims] 1. An objective eye refractive power measuring apparatus for objectively measuring the refractive power of an eye to be inspected, comprising: a visible light source for projecting visible light to the eye to be inspected; and the eye to be inspected projected from the visible light source. An observation optical system for guiding the visible light reflected by the imaging device, an imaging unit for imaging the visible light guided by the observation optical system, and an image for displaying an image captured by the imaging unit. An objective eye refractive power measuring device, comprising: a display unit. 2. The objective type eye refractive power measuring device according to claim 1, wherein said visible light source is a white LED. 3. The apparatus according to claim 1, wherein a plurality of the visible light sources are provided, and the plurality of the visible light sources are arranged at positions where the visible light can be projected onto the eye to be examined at different angles. Objective eye refractive power measuring device according to Item 1. 4. An objective type eye refractive power measuring apparatus according to claim 1, wherein said image pickup means is a color image pickup device. 5. The objective eye refractive power measurement according to claim 1, further comprising a light amount adjusting means for arbitrarily adjusting the amount of visible light projected from said visible light source. apparatus.