JP2842999B2 - Visual stimulus display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a visual stimulus display in a visual stimulator for applying a visual stimulus to a human body.

[0002]

2. Description of the Related Art A magnetoencephalograph is a device for measuring a weak magnetic field in the brain caused by a stimulus to the human body.
It is used to diagnose mental illness and to study brain mechanisms. Conventionally, a magnetic flux sensor such as a SQUID (superconducting quantum interferometer) has been used as the detection unit. There are various methods for giving a stimulus to the human body, and one of them is a visual stimulus.

A visual stimulating device is a device for visually stimulating and inducing a magnetic field in the brain, and is described, for example, in Japanese Patent Application Laid-Open No. 6-181901. In such a conventional apparatus, a stripe pattern, a checker pattern, or the like is periodically displayed as a stimulus pattern on a visual stimulus display in reverse, so that a visual stimulus is given to a subject who looks at the display.

Since the magnetic field generated in the brain is extremely weak, the presence of a magnetic substance near the magnetic field detector is easily affected by the presence of the magnetic substance. For this reason, the visual stimulus display in the above-mentioned conventional example is constituted by a plurality of prismatic light transmitting members arranged in a two-dimensional array to which light emitting end faces from a plurality of non-magnetic optical fibers are joined.

[0005] According to the above-mentioned conventional example, a large helmet-shaped magnetic field measuring means is mounted on the head of a subject while the subject is sitting on a chair. The visual stimulus display is arranged slightly above the visual field in front of the subject sitting on the chair, and the subject looks up at the visual stimulus display.

[0006]

In the measurement of the magnetic field in the brain by visual stimulus, a viewpoint (hereinafter, referred to as a “fixed viewpoint”) is fixedly set on a display surface for displaying a stimulus pattern. It is necessary to periodically invert and display surrounding or nearby display patterns while continuously paying attention to the viewpoint. Then, it is necessary to switch and set the fixation point to various positions on the display surface.

However, Japanese Patent Application Laid-Open No. 6-181901 does not consider such formation and switching of a fixed viewpoint at all.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a display unit dedicated to visual stimulation having a fixed viewpoint for visual stimulation.

Another object of the present invention is to enable switching between a plurality of fixation points.

[0010]

In order to achieve the above object , the present invention provides a display body in which a plurality of display elements each having a rectangular light emitting surface are arranged in a two-dimensional group, and a display of the display body. a display pattern switching unit for periodically reversing the pattern, set vignetting on the display surface of the display body, wherein the display element
A plurality of light emission fixation points having a light emission surface smaller than the light emission surface of the child, and a fixation point selection for selecting light emission of the plurality of light emission fixation points.
And selecting section, only containing, selected by the fixation point selection unit
The display pattern displayed on the display body during the emission of the light emission fixation point
Turn characterized in that it is periodically highlighted.

[0011]

[0012]

Preferably, the light emitting fixation point is constituted by an end face of an optical fiber , and more preferably, the light emitting fixation point is provided.
Is constituted by an oblique end face of an optical fiber.

[0014]

According to the above arrangement, since the fixation point is formed on the display surface in advance, if the subject is continuously focused on the fixation point and the display pattern is periodically switched in that state, the object is fixed. A visual stimulus can be given to the examiner. Special
In addition, the light emission surface of the light emission fixation point is higher than the light emission surface of each display element.
Is also set small and positioned as a point light source
The individual rectangular light-emitting blocks that make up the light-emitting pattern
(Light emitting surface of the display element)
Can effectively demonstrate its original function
You.

It is desirable that the fixation points are provided at the periphery and the center of the display surface. When a plurality of fixation points are formed in this way, it is necessary to be able to select one of them.

If the fixation point is constituted by the end face of the optical fiber which is a non-magnetic member, the fixation point can be formed with a simple structure.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of a visual stimulus apparatus to which a visual stimulus display according to the present invention is applied. This visual stimulator is used in combination with a device that measures a weak magnetic field in the brain induced by visual stimulus. In this embodiment, the magnetic field in the brain is detected by applying an MRI apparatus in particular. The system is shown.

In FIG. 1, a subject 12 is laid on a movable bed 10 on his or her back. A visual stimulator 14 is fixed to the bed 10, and the visual stimulator 14 gives a visual stimulus to the subject 12. M
A cavity is formed in the gantry 16 of the RI apparatus, and the subject 12 is inserted into the cavity along with the bed 10. The diameter of the cavity of the gantry 16 is only about 50 cm, and accordingly, the height of the entire visual stimulator mounted on the bed 10 is reduced to about 35 cm. 16 will not collide.

The structure of the visual stimulus device 14 will be described. All the components of the visual stimulator described below are made of non-magnetic components. On the base 20, a prismatic frame 21 having a rectangular cross section in the horizontal direction is arranged upright. A pair of flat arms 23 (only one arm is shown in FIG. 1) is provided on the side surface of the frame 21 so as to sandwich the head. A pair of arms 23
Is rotatably supported by a pin 26, which is fixed by a lock mechanism (not shown). A knob 24 is rotatably attached to the distal ends of the pair of arms 23, and a pad (not shown) is fixed to the end of the knob 24 at the end on the head side. When the knob is rotated, the pad moves. Then, the head can be fixed by sandwiching it from the left and right.
That is, when viewed from above, the subject's head is sandwiched between the pads from both sides. This is to prevent the movement of the head during the visual stimulus and to stably detect the brain magnetic field. It should be noted that, even when an MRI image is formed, it is necessary to fix the head, which is the portion to be examined, and the above-described head holding mechanism is used. The arm 23 may be configured to be able to move up and down according to the size of the head.

A concave-shaped surface coil unit 18 for detecting a magnetic field is arranged below the head of the subject 12 and covers a part of the lower part of the head.

A base 32 is horizontally arranged above the frame 21, and the display unit 28 slides on the base 32. Specifically, the gear 36 meshes with a rack 34 formed below the display unit 28, and the rotation of the gear 36 is controlled by rotating the shaft of the gear 36 by a knob (not shown). The movement is converted into a horizontal movement of the display unit 34, and the display unit 28 can be slid to a desired position.

A display surface 38 is provided at the front of the display unit 28.
The visual stimulus display 38 according to the present invention while standing A vertically
Are arranged, and a large number of optical fibers in the optical fiber cable 30 are led to each display element. The structure of the visual stimulus display 38 will be described later in detail.

A pair of plates 33 extend above the vicinity of the nose of the subject at predetermined intervals in the width direction of the head above the frame 21, and a reflecting unit 40 is provided at the tip of the pair of plates 33. Is provided. The reflection unit 40 is for displaying the visual stimulus display image on the display surface 38A to the subject with a natural line of sight. A reflecting mirror 41 is provided in the field of view of the subject so that the angle can be adjusted. The reflecting mirror 41 is attached rotatably about a central axis 44, and is urged to the reflecting mirror 41 in a clockwise direction in FIG. On the other hand, the inclined plate 42
Is provided with an angle adjusting knob 48 as an angle adjusting mechanism, and a tip of a shaft 50 of the knob 48 is in contact with a lower part of the reflecting mirror 41. That is, the reflecting mirror 4 is
While a biasing force acts on 1 in a clockwise direction, the rotation of the reflecting mirror 41 is restricted by the shaft 50. Therefore,
By rotating the knob 48, the shaft 50 moves forward and backward, and as a result, the angle of the reflecting mirror 41 is adjusted.

In a relaxed and natural state, the human gaze does not face in the direction perpendicular to the central axis of the head (vertical direction 102 in FIG. 1), but in the direction inclined slightly toward the nose. It has been confirmed by experiments that it is facing. If the direction is defined as a natural line-of-sight direction, the natural line-of-sight direction is a direction inclined by about 20 degrees from the vertical direction 102. In FIG. 1, the natural line-of-sight direction is indicated by 100. It is considered that such inclination in the natural line of sight does not depend on whether a human is standing or lying down.

In this embodiment, a reflecting mirror 41 is provided on the natural line of sight 100. That is, the rotation axis 44 of the reflecting mirror 41 is located on the natural line of sight 100. As a result, if the subject keeps the eyeball in a natural state, the visual stimulus display image reflected on the reflector 41 can be viewed as it is. If the reflecting mirror 41 is set in the vertical direction 102, it will be slightly more noticeable than in a natural state, and the fatigue degree will increase in a long-time measurement.
The line of sight shifts to other scenes (objects) seen through the lower space.

At the upper end of the inclined plate 42, a horizontal plate 52 is formed to extend to the upper part of the eyeball. On the lower surface of the horizontal plate 52, a positioning mirror 54 is arranged on a vertical line 102.

FIG. 2 is a sectional view showing a specific structure of the positioning mirror 54. A cover 7 is provided on the lower surface of the horizontal plate 52.
The mirror 72 covered with the mirror 4 is arranged, and a part of the surface of the mirror 72 is exposed from the slit 54A. The slit 54A has an elongated shape of, for example, 80 mm × 5 mm corresponding to both eyes. Therefore, the portion that substantially functions as a mirror is the portion of the slit 54A. Of course, the mirror 72 itself may be formed horizontally long.

In FIG. 1, this positioning mirror 54 is used by the subject 12 to position his / her body (particularly the head) when the subject 12 lies on the bed 10.
Used to do. That is, in a state where the bed 10 is discharged from the cavity of the gantry 16, when the subject lies on his / her back on the bed 10, the head of the subject 12 is appropriately positioned with reference to the visual stimulator 14. Although necessary, the subject 12 can easily position the head by the subject 12 staring at the positioning mirror 54 by himself and moving his / her head so that his / her eyes can be seen there. .

As shown by reference numerals 106 and 108 in FIG. 2, when the subject's head is shifted toward the tip of the bed 10 or in the opposite direction, his / her eyes cannot be projected on the positioning mirror 54. When one's own eyes are projected, it is the proper position of the head, and the natural gaze in that state is reflected by the reflecting mirror 41.
Will pass through. In the present embodiment, since the elongated slit 54A is formed, as shown by 110 in FIG. 3, even if the center position of the head is appropriate, if the neck is bent, two eyes or one of the two eyes Your eyes will not be reflected in the mirror. Therefore, when the two eyes are projected, the head is in a straightened state and its position is also appropriate (see 104 in FIG. 2 and 112 in FIG. 3). When the head is positioned in this way, the position is fixed and maintained by the head holding mechanism as described above.

FIG. 4A shows a display surface 38A of the visual stimulus display 38 according to the present invention, and FIG. 4B shows a cross section thereof. The visual stimulus display 38 is a prismatic display element (transparent element) made of plastic, glass, or the like.
A display body 62 in which 64 are arranged two-dimensionally in a vertical and horizontal manner;
It includes a lattice-shaped light-blocking block 68 disposed behind the display 62 and a holding block 70 disposed behind the light-blocking block 68.

The display element 64 has a light-emitting surface 64B and a light-receiving surface 64A formed to be several mm × several mm, and the length is several cm. 4 of the display element to perform light separation from each other
On one side, a light reflection layer is formed as in the conventional case.

The holding block 70 holds the ends of a plurality of optical fibers 66 for guiding light to the light receiving surface 64A of each display element 64, corresponding to each display element 64. In particular,
The end of the optical fiber 66 is held so that the fiber end face is separated from the light receiving surface 64A by about 10 mm.

FIG. 5 illustrates the reason. In the comparative example shown in FIG. 5A, the light receiving surface 64 of the display element 64
A and the light exit end face 66A of the optical fiber 66 are joined. The intensity distribution of light emitted from the optical fiber 66 is shown in FIG.
(A) has a characteristic shown by reference numeral 124 in FIG.
When both surfaces are joined as in (A), only the central portion of the light emitting surface 64B has high luminance and the peripheral portions (especially, the four corners) are in a light emitting state dark as indicated by 120 in FIG. In order to increase the degree of visual stimulus to the subject, it is necessary to perform display so that the boundaries between adjacent light-emitting surfaces are as clear as possible.

Therefore, in this embodiment, after the light exit end face 66A of the optical fiber 66 is moved away from the light receiving surface 64A to increase the degree of dispersion, the light from the optical fiber 66 is transmitted to the light receiving surface 6A.
4A. By employing the structure shown in FIG. 5B, light can be uniformly emitted to the four corners of the rectangular light emitting surface as indicated by 122.

Of course, the light receiving surface 64A and the light emitting end surface 66A
A light diffusion medium may be provided between the first and second light diffusion media. However, according to the configuration of this embodiment, it is possible to avoid light attenuation and cost increase when such a light diffusion medium is used.

If the light emitting end face 66A is simply moved away, the light may sneak into the light receiving surface 64A of the adjacent display element 64. Therefore, in the present embodiment, a light-blocking block 68 that blocks and separates the space between the light-receiving surface 64A and the light-emitting end surface 66A for each display element 64 is provided. The light shielding block 68 is formed in a lattice shape, and light emitted from the light emitting end face 66A is introduced only to the light receiving surface 64A of the corresponding display element 64. If the housing surrounding the display 38, the light-blocking block 68, and the holding block 70 are integrally formed, the cost can be reduced.

In FIG. 4, (A) is displayed on the display surface 38A.
9 fixed points P1 to P at the periphery and center as shown in FIG.
9 are formed. The fixation point is a light emitting point that is noticed by the subject when a visual stimulus is given, and an image of one of the patterns as a background is obtained while the eye of the subject is focused on the fixation point. It is highlighted and it lasts for a few minutes.

In this embodiment, the fixation points P1 to P9 are formed by exposing the end faces of the optical fiber. If the area of the light emitting surface is too small and the attention on the fixation point is heavy,
As shown in (2), the end of the optical fiber for fixation may be cut off obliquely, and the exposed surface may be used as the light emitting surface. In addition, the center fixation point P5 may be obtained by cutting out the corners of the four display elements 64 as shown in FIG. 7, and the end face of the optical fiber for fixation point may be desired in the formed diamond-shaped space. . Alternatively, as shown in FIG.
The oblique end face as described above may be located at the center.

The visual stimulus display includes an inverted display of a checker pattern and an inverted display of a vertical or horizontal stripe pattern. The display color may be a color with the strongest stimulus.

A visual stimulus controller (not shown) is usually installed outside the magnetically shielded room, and a fiber optic cable 30 exiting from the display unit 28 is directly connected or connected via a photoelectric converter. The visual stimulus controller can select a fixation point, adjust the fixation point intensity, select a stimulus pattern, set a cycle of inverted display, adjust a stimulus display intensity, and the like.

Next, the operation of this embodiment will be described.

First, the subject lies on the bed 10 discharged outside the cavity of the gantry 16. At this time, the subject himself / herself adjusts the position of the head so that the two left and right eyes of the subject appear on the positioning mirror 54. After positioning the head, the head is fixedly maintained by the head holding mechanism. That is,
It is clamped by two arms 23.

When the head is positioned, the reflecting mirror 41 is positioned in the natural line of sight. Therefore, the angle of the reflecting mirror 41 is adjusted while turning the knob 48, and the display surface 3 is adjusted.
The visual stimulus image displayed on 8 </ b> A is projected on the reflecting mirror 41. In this case, the angle of the reflecting mirror 41 is adjusted according to the eye level of the subject.

When detecting a weak magnetic field, a metal (magnetic member)
The subject wearing the glasses needs to remove the glasses. According to the configuration of the present embodiment, the display unit 28 can be moved and adjusted in the horizontal direction even if the spectacles are removed, so that the display surface 38A can be moved back and forth according to the visual acuity. That is,
The total path of the line-of-sight lengths 100 and 100 'can be set freely. For example, as the line-of-sight length is 18 cm to 30 cm
Although the degree can be varied, it is needless to say that a larger variable range may be provided. In any case, in this embodiment, the visual stimulus is given by using the reflection of the mirror, so even if there is not enough space in front of the subject's head (upward in the state of FIG. 1), A sufficient gaze length can be secured.

Angle Adjustment of Reflecting Mirror 41 and Display Unit 2
After the position adjustment (gaze length adjustment) of Step 8 is completed, visual stimulation is executed, and the subject 12 is inserted into the cavity of the gantry 16 together with the bed 10 (the state of FIG. 1). Then, in that state, the measurement of the magnetic field in the brain is performed using the surface coil unit 18. M if possible
RI measurement may be performed to capture a tomographic image of the brain.

In the visual stimulus, first, one of the fixation points is turned on, and the subject is instructed to maintain the line of sight at the fixation point, and in this state, the pattern of the display surface serving as the background is shortened. This is achieved by inverting display or the like periodically. Then, if necessary, the position of the fixation point is changed, and the same display as described above is executed.

[0048]

As described above, according to the present invention,
It is possible to provide a display for visual stimulation in which the luminescent fixation point is incorporated in advance on the display surface. Further, since a plurality of fixation points can be easily switched by remote control, the total measurement time can be shortened as compared with the change of fixation points which requires an artificial operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a visual stimulus device to which a visual stimulus display according to the present invention is applied.

FIG. 2 is a sectional view of a positioning mirror.

FIG. 3 is an explanatory diagram showing a function of a positioning mirror.

FIG. 4 is a diagram showing a plane and a cross section of a visual stimulus display according to the present invention.

FIG. 5 is an explanatory diagram showing a difference between a case where an output end face of an optical fiber is close to a light receiving surface of a display element and a case where the end face is separated therefrom.

FIG. 6 is a diagram illustrating an example of an end shape of an optical fiber for a fixed viewpoint;

FIG. 7 is a diagram showing an example of forming a fixation point.

[Explanation of symbols]

 Reference Signs List 12 subject 14 visual stimulator 16 gantry 18 surface coil unit 28 display unit 30 optical fiber cable 38 visual stimulus display 40 reflecting unit 41 reflecting mirror 54 positioning mirror 62 display 64 display element 68 light shielding block 70 holding blocks P1 to P9 Fixation point

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-217941 (JP, A) JP-A 2-147045 (JP, A) JP-A-63-5724 (JP, A) JP-A-51- 53788 (JP, A) JP-A 60-104105 (JP, U) JP 6-16748 (JP, B2) JP 5 54776 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) A61B 5/05 A61B 5/16

Claims (3)

(57) [Claims] 1. A display body in which a plurality of display elements each having a rectangular light emitting surface are two-dimensionally arranged and arranged; a display pattern switching unit for periodically inverting a display pattern of the display body; setting vignetting of the display surface, the light emitting surface of the display device
A plurality of light emission fixation points having a smaller light emission surface, and a fixation point selection unit for selecting light emission of the plurality of light emission fixation points
When, only contains the fixation point emission of the selected light emitting fixation point by the selection unit
While the display pattern displayed on the display is periodically
Visual stimulus indicator, characterized in that it is highlighted. 2. The visual stimulus display device according to claim 1, wherein the light emission fixation point is constituted by an end face of an optical fiber . 3. The display according to claim 1 , wherein the light emission fixation point is formed by an oblique end face of an optical fiber.
A visual stimulus display characterized by the following.