JP2012183289A - Visual target presentation device - Google Patents

Abstract

An object of the present invention is to reduce the width of an apparatus while presenting an image of an observation target as a target without worrying about distortion of the target to the observer.
An optotype presenting apparatus is an apparatus that presents an observation target image as an optotype to an observer. The optotype presenting apparatus projects a display device 1 that projects an observation target, a beam splitter 2 that has a split surface 21 that divides light emitted from the display device 1 into reflected light and transmitted light, and reflected light. And a concave mirror 3 having a mirror surface 31 for forming an image. The beam splitter 2 and the concave mirror 3 are arranged so that the reflected light 24 projected onto the center point 32 of the mirror surface 31 is inclined toward the display device 1 with respect to the normal 33 at the center point 32. The dividing surface 21 of the beam splitter 2 is formed in a non-planar surface.
[Selection] Figure 1

Description

  The present invention relates to an optotype presenting apparatus that presents an observer with an image to be observed as an optotype.

  In recent years, with the advancement of information technology, work using a visual terminal device (VDT: Visual Display Terminal) (hereinafter referred to as “VDT work”) is increasing. Advances in information technology can greatly improve work efficiency and work accuracy.

  However, long-time VDT work gives eyestrain to the worker. Similar eye fatigue occurs when a television monitor is viewed for a long time. When the user gazes at the display screen of the visual terminal device or the television monitor at a short distance, the ciliary muscle that is the driving source of the focus adjustment function of the eye is in a tension state. The tension state of the ciliary muscle contributes to eye strain.

  In order to reduce eye strain as described above, it is desirable for the user to view far away.

  In view of this, conventionally, there has been proposed an optotype presenting apparatus that reduces the eye strain by presenting the optotype at a distance using a concave mirror and a half mirror (for example, Patent Document 1). As shown in FIG. 17, the conventional optotype presenting apparatus includes a half mirror 92 obliquely intersecting with the optical axis of the light emitted from the display device 91 at 45 ° (angle θ2 = 45 °) with the display device 91. It is arranged between the concave mirror 93. The mirror surface 931 of the concave mirror 93 is a spherical surface. The optical axis 933 of the concave mirror 93 coincides with the optical axis of the reflected light divided by the half mirror 92 and projected onto the center point 932 of the concave mirror 93. The light for projecting the observation target is reflected by the half mirror 92 toward the concave mirror 93, and a virtual image of the observation target is formed by the concave mirror 93. The observer can observe the virtual image of the observation object through the half mirror 92.

  The principle of the target presentation when the concave mirror 93 is used as in the target presentation apparatus will be described. When the observation target is closer to the concave mirror 93 than the focal position of the concave mirror 93, the concave mirror 93 forms a virtual image of the observation target. The distance A2 between the concave mirror 93 and the virtual image is expressed by the distance A1 between the concave mirror 93 and the observation target and the focal length f as shown in Expression (1). In addition, the size B2 of the virtual image to be observed is expressed as in Expression (2) by the size B1 of the observation target and the focal length f.

A2 = A1 * f / (A1-f) (1)
B2 = B1 × | f | / | A1-f | (2)
In the target presentation device, a virtual image formed when an observation target is placed between the center point 932 of the concave mirror 93 and the focal position is used as a target. For example, when a concave mirror 93 composed of a spherical surface having a focal length f = 150 mm and a curvature radius of 300 mm is used, the distance A2 = −0.3 m when the distance A1 = 100 mm, and the distance A2 = −11. 0m. The position of the virtual image can be farther than the observation target.

  As described above, the conventional optotype presenting apparatus can distant the position of the virtual image as the optotype on the observer's line of sight, and can reduce the eye strain of the observer gazing at the optotype. .

International Publication No. 2010/050504

  The target presentation device as described above is used when an observer observing the target performs a VDT work or a viewing act. Therefore, it is necessary to consider installation in a general VDT workplace or residence.

  However, the conventional optotype presenting apparatus is arranged so that the half mirror 92 is obliquely crossed at 45 ° (angle θ2 = 45 °) with respect to the optical axis 933 of the display device 91 and the concave mirror 93 as shown in FIG. Therefore, there is a problem that the depth of the apparatus (width in the direction of the optical axis 933) becomes thick and the installation place is limited.

  When solving the above problem, it is not preferable that the distortion of the visual target increases as compared with the conventional visual target presenting apparatus.

  The present invention has been made in view of the above points, and an object of the present invention is to reduce the width of the apparatus while presenting an image of an observation target as a target without causing the observer to worry about distortion of the target. An object of the present invention is to provide an optotype presenting apparatus capable of performing the above.

  An optotype presenting apparatus according to the present invention is an optotype presenting apparatus that presents an observer with an image of an observation target as a target, and reflects a light emitted from the projection unit that projects the observation target and the projection unit A beam splitter having a split surface that divides light into transmitted light and a concave mirror that has a mirror surface on which the reflected light is projected and forms the image, and the reflected light projected on a center point of the mirror surface The beam splitter and the concave mirror are disposed so as to be inclined toward the projection unit with respect to a normal line at the center point, and the splitting surface of the beam splitter is formed in a non-planar shape.

  In this optotype presenting apparatus, the image is preferably a virtual image.

  In this optotype presenting apparatus, it is preferable that the split surface of the beam splitter is formed to be convex toward the concave mirror side.

  In this optotype presenting apparatus, the image is preferably a real image.

  In this optotype presenting apparatus, it is preferable that the split surface of the beam splitter is formed to be convex toward the side opposite to the concave mirror.

  In this optotype presenting apparatus, it is preferable that the mirror surface of the concave mirror is formed as an aspherical surface.

  The target presentation device preferably includes a distance adjusting unit that changes an optical distance between the observation target and the concave mirror.

  In this optotype presenting apparatus, the projection unit includes a light source that emits light for projecting the observation target, a projection-side beam splitter that divides the light emitted from the light source into reflected light and transmitted light, and It is preferable to have a projection-side concave mirror that reflects the reflected light divided by the projection-side beam splitter to the beam splitter side.

  In this optotype presenting apparatus, it is preferable to include a projection-side distance adjusting unit that changes an optical distance between the light source and the projection-side concave mirror.

  In the present invention, the beam splitter and the concave mirror are arranged so that the reflected light projected on the center point of the mirror surface of the concave mirror is inclined to the projection unit side with respect to the normal line, and the split surface of the beam splitter is formed to be non-planar. Yes. Thereby, in this invention, the width | variety of an apparatus can be made thin, without increasing the distortion of the image used as a target. That is, according to the present invention, the width of the device is reduced compared to the width of the conventional target presenting device while presenting the image of the observation target as a target without worrying about the distortion of the target to the observer. can do.

1 is a schematic diagram of an optotype presenting apparatus according to Embodiment 1. FIG. It is sectional drawing which shows the structure of the optotype presenting apparatus which concerns on the same as the above. It is a figure explaining the design parameter of the optotype presenting apparatus which concerns on the same as the above. In the optotype presenting apparatus according to the above, (a) is a diagram showing a distortion lattice of a virtual image when the viewing distance is 0.5 m, and (b) is a distortion lattice of the virtual image when the viewing distance is 5.0 m. FIG. It is the schematic of the optotype presenting apparatus concerning Embodiment 2. It is a figure explaining the design parameter of the optotype presenting apparatus which concerns on the same as the above. In the optotype presenting apparatus according to the above, (a) is a diagram showing a distortion lattice of a virtual image when the viewing distance is 1.0 m, and (b) is a distortion lattice of the virtual image when the viewing distance is 5.0 m. FIG. It is the schematic of the optotype presenting apparatus concerning Embodiment 3. It is the schematic of the optotype presenting apparatus concerning Embodiment 4. It is the schematic of the optotype presenting apparatus concerning Embodiment 5. It is the schematic of the optotype presenting apparatus concerning Embodiment 6. It is a figure explaining the design parameter of the optotype presenting apparatus which concerns on the same as the above. In the optotype presenting apparatus according to the above, (a) is a diagram showing a real image distortion grid when the viewing distance is 400 mm, and (b) is a diagram showing a real image distortion grid when the viewing distance is 410 mm. . It is the schematic of the optotype presenting apparatus whose division surface of a beam splitter is a plane. In the optotype presenting apparatus in which the split plane of the beam splitter is a plane, (a) is a diagram showing a distortion grating of a virtual image when the viewing distance is 0.5 m, and (b) is a case where the viewing distance is 5.0 m. It is a figure which shows the distortion grating | lattice of a virtual image. In an optotype presenting apparatus in which the splitting plane of the beam splitter is a plane, (a) is a diagram showing a real image distortion grating when the viewing distance is 400 mm, and (b) is a real image distortion when the viewing distance is 410 mm. It is a figure which shows a grating | lattice. It is the schematic of the conventional optotype presenting apparatus.

  In the following first to sixth embodiments, an optotype presenting apparatus that presents an observer with an image to be observed as an optotype will be described.

(Embodiment 1)
As shown in FIG. 1, the optotype presenting apparatus according to the first embodiment includes a display device 1 that displays an observation target, and a beam splitter 2 that divides light emitted from the display device 1 into reflected light and transmitted light. And a concave mirror 3 on which the reflected light (all reflected light including the reflected light 24) divided by the beam splitter 2 is projected. Furthermore, the optotype presenting apparatus according to the present embodiment includes a moving device 4 that moves the display device 1 as shown in FIG. The optotype presenting apparatus according to the present embodiment presents a virtual image formed by the concave mirror 3 to the observer as an optotype.

  The display device 1 is a small flat panel display and includes a display surface 11 for displaying an observation target as shown in FIG. Examples of the small flat panel display used as the display device 1 include a liquid crystal panel or an organic electro-luminescence (hereinafter referred to as “organic EL”) display. The display surface 11 is a flat surface, and light emitted from the display surface 11 is light having the normal line of the display surface 11 as an optical axis. The display device 1 displays the observation target on the display surface 11 and projects it onto the beam splitter 2. The display device 1 of this embodiment has a function of a projection unit. The observation target displayed on the display surface 11 of the display device 1 is not particularly limited, and may be an image according to the preference of the observer, such as a document, a still image (photo, picture), a moving image (video), or a game.

  The display device 1 has a function of easily controlling switching of a display image (observation target), image processing on the display image, and the like. The display device 1 also has a function for correcting distortion, brightness, and display size of the display image in accordance with the position of the virtual image. Thereby, the observer's consciousness about the movement of the virtual image can be reduced, and the observer can be concentrated on the VDT work or the viewing act like the conventional VDT or television monitor.

  The beam splitter 2 is a half mirror, and has a dividing surface 21 that divides light emitted from the display device 1 into reflected light and transmitted light. The concave mirror 3 has a mirror surface 31 on which the reflected light (all reflected light including the reflected light 24) divided by the beam splitter 2 is projected.

  The beam splitter 2 and the concave mirror 3 are arranged as shown in FIG. That is, the beam splitter 2 and the concave mirror are arranged such that the reflected light 24 projected onto the center point 32 of the mirror surface 31 of the concave mirror 3 is inclined toward the display device 1 (upper side in FIG. 1) with respect to the normal 33 at the center point 32. 3 is arranged. In other words, the reflected light 24 is inclined counterclockwise with respect to the normal 33 around the Y axis in FIG. The splitting surface 21 of the beam splitter 2 rises in a direction facing the mirror surface 31 of the concave mirror 3 (left side in FIG. 1) as compared to the conventional half mirror 92.

  The beam splitter 2 is arranged as described above with respect to the concave mirror 3, and the angle θ <b> 1 formed by the tangent plane 23 of the point 22 on the dividing surface 21 and the optical axis of the display device 1 with respect to the display device 1. Is arranged to be less than 45 °. A point 22 on the dividing surface 21 is a point where the reflected light 24 projected on the center point 32 of the mirror surface 31 of the concave mirror 3 is generated. The beam splitter 2 is not necessarily a half mirror, and may be a non-planar plate-like beam splitter other than the half mirror.

  The splitting surface 21 of the beam splitter 2 is formed to be non-planar (curved surface) so as to reduce the distortion of the virtual image of the display image (observation target) imaged by the concave mirror 3 as compared with the case where the splitting surface is a flat surface. ing. Specifically, the splitting surface 21 of the beam splitter 2 is formed in a spherical surface that is convex toward the concave mirror 3 side.

  The concave mirror 3 is arranged so that the optical distance between the virtual image (hereinafter referred to as “second virtual image”) formed by the beam splitter 2 and the concave mirror 3 is shorter than the focal length. The second virtual image is an image formed by the reflected light reflected by the beam splitter 2 out of the light emitted from the display device 1. The concave mirror 3 forms a virtual image of the display image by projecting the second virtual image. That is, the concave mirror 3 forms a virtual image of the display image by projecting the display image (observation target) displayed on the display device 1 through the beam splitter 2. The mirror surface 31 of the concave mirror 3 is formed in an elliptical surface (aspherical surface) so as to reduce distortion of the virtual image of the display image from the spherical surface. That is, the concave mirror 3 of the present embodiment is an elliptical mirror (aspherical mirror) shaped so as to reduce the distortion of the virtual image of the display image as compared with the case of the spherical mirror. The mirror surface 31 of the concave mirror 3 does not necessarily have to be an elliptical surface as described above, and may be an aspherical surface that reduces the distortion of the virtual image of the display image from the spherical surface.

  The virtual image of the display image passes through the beam splitter 2 and is presented to the observer as a visual target. The observer's observation point 8 is located in front of the concave mirror 3 (left side in FIG. 2). The virtual image of the display image can be reduced in chromatic aberration by reducing the plate thickness of the beam splitter 2 as compared with the case of using a prism type beam splitter.

  In the optotype presenting apparatus of the present embodiment, as shown in FIG. 3, the display device 1 is arranged so that the height L1 from the lowest position of the concave mirror 3 can move between 155 mm and 390 mm, and the Y axis of the concave mirror 3 The length L2 in the direction is 160 mm, and the length L3 in the Z-axis direction is 120 mm. In the X-axis direction, the distance L4 between the beam splitter 2 (point 22) and the concave mirror 3 (center point 32) is 100 mm, and the distance L5 between the beam splitter 2 (point 22) and the observation point 8 is 100 mm. It is. In addition, said height L1, length L2, L3, and distance L4, L5 are examples, and are not limited to said value, It sets suitably according to a use.

  As shown in FIG. 4, the virtual image (solid line in FIG. 4) of the display image (observation target) in the optotype presenting apparatus according to the present embodiment is when the split surface 941 of the beam splitter 94 as shown in FIG. 14 is a plane. Compared to (see the solid line in FIG. 15), distortion is reduced. FIG. 4 shows an example of this embodiment in which the radius of curvature of the splitting surface 21 of the beam splitter 2 is 450 mm and the conic constant k is 0.0, the radius of curvature of the mirror surface 31 of the concave mirror 3 is 380 mm, and the conic constant k. The distortion lattice of a virtual image in case where is −0.6 is shown. 4A shows a case where the viewing distance is 0.5 m, and FIG. 4B shows a case where the viewing distance is 5.0 m. The curvature radii and the conic constant k of the beam splitter 2 and the concave mirror 3 are not limited to the above values, and are appropriately set according to the application. The broken lines in FIGS. 4 and 15 indicate display images.

  As described above, when the beam splitter 2 is arranged so that the reflected light 24 projected onto the center point 32 of the mirror surface 31 of the concave mirror 3 is inclined toward the display device 1 with respect to the normal line 33, the beam splitter 2 is divided. By making the surface 21 non-planar (spherical), the distortion of the virtual image can be reduced as compared with the case of a beam splitter whose dividing surface is a plane.

  As shown in FIG. 2, the moving device 4 is a moving mechanism of the display device 1, and includes a holding plate 41, a linear guide 42, a feed screw 43, a pulley 44, a pulley belt 45, a motor 46, and a control. Part 47. The moving device 4 changes the optical distance between the display image (observation target) displayed on the display device 1 and the concave mirror 3 by moving the display device 1, and the second virtual image (to the beam splitter 2). The optical distance between the imaged virtual image) and the concave mirror 3 is changed. That is, the moving device 4 has a function of a distance adjusting unit.

  The holding plate 41 holds the display device 1. The linear guide 42 supports the holding plate 41. The motor 46 is an electronic motor serving as a drive source for the moving device 4. The pulley 44 and the pulley belt 45 transmit the rotational driving force of the motor 46 to the feed screw 43. The control unit 47 controls the motor 46. That is, the moving device 4 realizes the vertical movement of the display device 1 by converting the rotational driving force generated by the motor 46 into a linear motion by the feed screw 43. At this time, the control unit 47 moves the display device 1 in the vertical direction so that the optical distance between the second virtual image and the concave mirror 3 is changed within a range shorter than the focal length of the concave mirror 3. The control unit 47 is, for example, a computer processing device. The computer may be a general-purpose computer such as a personal computer, or may be a computer dedicated to the optotype presenting apparatus.

  As described above, when the moving device 4 moves the display device 1 up and down, the optical distance between the display image (observation target) displayed on the display device 1 and the concave mirror 3 changes. When the optical distance changes, the optical distance between the virtual image of the display image and the observation point 8 changes.

  Next, the moving range of the virtual image will be described. From the expression (1) indicating the positional relationship between the display image (observation target) displayed on the display device 1 and the virtual image, the virtual image rapidly moves to infinity as the display device 1 approaches the focal position of the concave mirror 3. . In addition, it is said that the closest point at which an observer in his twenties can clearly see the target (virtual image), that is, the adjustment near point, is an average of 0.118 m (about 8.5 diopters). Therefore, it is sufficient that the closest position (nearest position) is a position where the distance between the observation point 8 and the virtual image is about −0.1 m. On the other hand, the farthest position (farthest position) may be a position where the distance between the observation point 8 and the virtual image is about −10 m (−0.1 diopter). The distance range between the observation point 8 and the virtual image as described above is a range in which a fatigue prevention effect for the focus adjustment function of the eye can be sufficiently obtained. The control unit 47 controls the motor 46 so as to move the display device 1 within a movement range set so as to include the farthest position and the nearest position.

  Further, the control unit 47 can freely set the moving speed of the display device 1 by controlling the rotation speed of the motor 46. Thereby, the display apparatus 1 can be moved at a speed according to a movement speed law adapted to the physiological aspect of the observer's eye.

  Next, the moving speed of the display device 1 under the control of the control unit 47 will be described. First, when the lens of the observer's eye is approximated to a thin convex lens, the distance s1 (<0) between the center point of the lens and the virtual image and the distance between the center point of the lens and the retina (imaging point). Between s2 (> 0) and the refractive power D of the crystalline lens, a relationship as shown in Expression (3) is established. The refractive power D is expressed in diopter units.

1 / s2 = 1 / s1 + D (3)
The focus adjustment function of the eye refers to a function that always forms an image on the retina by changing the refractive power D of the lens according to the distance s1 between the center point of the lens and the virtual image. As can be seen from Equation (3), the longer the distance s1 between the center point of the crystalline lens and the virtual image is, the smaller the degree of the time change of the distance s1 exerted on the time change of the refractive power D (refractive power change). That is, when the distance s1 is short (in the case of a short distance) and long (in the case of a long distance), even if the time change of the distance s1 is the same, the influence of the time change of the distance s1 on the refractive power change Different. When the distance is short, the time change of the distance s1 has a great influence on the refractive power change, and when the distance is long, the influence of the time change of the distance s1 on the refractive power change is small. If it is desired to obtain the same change in refractive power regardless of the length of the distance s1, it is necessary to increase the time change of the distance s1 as the distance s1 increases. Note that the distance s2 between the center point of the crystalline lens and the retina hardly changes, and can be approximated to the diameter φ of the eyeball. When the focus adjustment function of the eye is functioning soundly, Equation (3) can be expressed by Equation (4).

1 / φ = 1 / s1 + D (4)
Here, it can be said that the stimulus applied to the focus adjustment function of the eye is greater than or equal to a certain value is that the temporal change | ∂D / ∂t | of the refractive power D of the lens is always greater than or equal to a certain value. Therefore, the condition for the stimulus applied to the focus adjustment function of the eye to be a certain level or more is expressed by Expression (5) from Expression (4). Γ represents a threshold value.

| ∂D / ∂t | = | ∂ (1 / s1) / ∂t |
= (1 / s1 ² ) × | ∂s1 / ∂t | ≧ Γ (5)
The control unit 47 sets the time change | ∂D / ∂t | of the refractive power D to a constant value (threshold value Γ) at all times, the time change of the reciprocal l / s1 of the distance s1 | ∂ (1 / s1) / ∂. The display device 1 may be moved by controlling the motor 46 so that t | becomes constant. In order to move the virtual image at a target speed, the moving speed of the display device 1 may be calculated with reference to Equation (1). The control unit 47 controls the operation of the motor 46 so that the moving speed of the display device 1 increases as the optical distance between the display device 1 and the concave mirror 3 increases. Thereby, the moving speed | 像 s1 / ∂t | of the virtual image can be increased as the display device 1 moves away from the observation point 8.

  As described above, the display device 1 is moved away from the observation point 8 by moving the display device 1 so that the time change | ∂ (1 / s1) / ∂t | of the reciprocal l / s1 of the distance s1 becomes constant. The moving speed of the virtual image can be effectively increased. Thereby, the eye strain of the observer can be reduced.

  Note that as the optical distance between the display device 1 and the concave mirror 3 becomes longer, that is, the second virtual image (the virtual image formed by the beam splitter 2) approaches the focal position of the concave mirror 3 and forms an image by the concave mirror 3. As the virtual image to be displayed approaches the far point, the enlargement ratio of the virtual image (the virtual image formed by the concave mirror 3) with respect to the display image increases. As a result, even if the optical distance between the concave mirror 3 and the virtual image changes, the size of the virtual image on the retina of the observer's eye becomes almost constant.

  The control unit 47 controls the motor 46 so as to repeat the reciprocating motion of the display device 1 by periodically and continuously moving the display device 1 between the concave mirror 3 and the focal position of the concave mirror 3. By repeating the reciprocating motion of the display device 1 as described above, the refractive power D of the observer's crystalline lens can be effectively changed, so that the eyestrain of the observer can be further reduced. In addition, by periodically reciprocating the display device 1, the refractive power D of the observer's crystalline lens can be changed more frequently, so that the fatigue of the observer's focus adjustment function can be further reduced. . Furthermore, since the virtual image can be moved gradually by moving the display device 1 continuously and continuously moving the optical distance between the display device 1 and the concave mirror 3, the movement of the virtual image is observed. It can be made not to notice it.

  Next, the operation of the optotype presenting apparatus according to the present embodiment will be described with reference to FIG. First, the observer turns to the concave mirror 3 through the splitting surface 21 of the beam splitter 2 and sees a virtual image of a display image (observation target) displayed on the display device 1. When the control unit 47 (see FIG. 2) starts to drive the motor 46 (see FIG. 2), the display device 1 starts to move upward. When the display device 1 moves to the upper limit position, the display device 1 starts moving downward. Thereafter, when the display device 1 moves to the lower limit position, the display device 1 starts to move upward. The display device 1 repeats the above operation. During this time, the observer continues to see the virtual image of the display image.

  As described above, in the visual target presenting apparatus of the present embodiment, the beam splitter 2 and the concave mirror are arranged so that the reflected light 24 projected onto the center point 32 of the mirror surface 31 of the concave mirror 3 is inclined toward the display device 1 with respect to the normal 33. 3 is arranged, and the splitting surface 21 of the beam splitter 2 is formed to be non-planar. Thereby, in the optotype presenting apparatus of the present embodiment, the width W1 of the apparatus can be reduced without increasing the distortion of the virtual image of the display image (observation target). That is, the optotype presenting apparatus according to the present embodiment reduces the observer's eye strain by presenting a virtual image farther than the display image as an optotype without worrying about the distortion of the optotype to the observer. While maintaining the advantage, the width W1 of the device can be made thinner than the width W2 of the conventional optotype presenting device (broken line in FIG. 1).

  In particular, in the optotype presenting apparatus of the present embodiment, the splitting surface 21 of the beam splitter 2 is formed in a convex shape toward the concave mirror 3, so that distortion of the optotype can be reduced more easily.

  Furthermore, in the optotype presenting apparatus according to the present embodiment, since the mirror surface 31 of the concave mirror 3 is an aspherical surface, the distortion of the optotype can be reduced more easily.

  Moreover, according to the optotype presenting apparatus of the present embodiment, the moving device 4 changes the optical distance between the display image displayed on the display device 1 and the concave mirror 3, thereby making the eye focus adjustment function unconscious. Since it can be changed, the eye strain of the observer can be further reduced.

  In particular, in the optotype presenting apparatus of this embodiment, the refractive power D of the observer's crystalline lens can be effectively changed by repeating the reciprocating motion of the virtual image, thereby further reducing the eyestrain of the observer. be able to.

  Furthermore, the optotype presenting apparatus according to the present embodiment increases the moving speed of the virtual image | ∂s1 / ∂t | as the optical distance between the display device 1 and the concave mirror 3 increases and the position of the virtual image increases. Thereby, not only when the virtual image is close to the observation point 8, but also when the virtual image is away from the observation point 8, the temporal change | ∂D / ∂t | it can. As a result, regardless of whether the virtual image is far away or close, the change in the focus adjustment function of the observer can always be made a certain level or more.

(Embodiment 2)
The optotype presenting apparatus according to the second embodiment is different from the optotype presenting apparatus according to the first embodiment in that it includes a projection-side beam splitter 5 and a projection-side concave mirror 6 as shown in FIG. In the present embodiment, the display device 1, the projection side beam splitter 5, and the projection side concave mirror 6 correspond to a projection unit. In addition, about the component similar to the optotype presenting apparatus of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The projection-side beam splitter 5 is a half mirror, is disposed on the optical path of the light emitted from the display device 1, and divides the light emitted from the display device 1 into reflected light and transmitted light at the dividing surface 51. The dividing surface 51 of the projection side beam splitter 5 is a flat surface. However, the dividing surface 51 of the projection-side beam splitter 5 is not necessarily a flat surface and may be a non-planar surface. The projection-side beam splitter 5 is not necessarily a half mirror, and may be a planar beam splitter other than the half mirror, or a prism type beam splitter.

  The projection-side concave mirror 6 is disposed on the optical path of the reflected light divided by the projection-side beam splitter 5, and reflects the reflected light divided by the projection-side beam splitter 5 to the beam splitter 2 side by the mirror surface 61. The mirror surface 61 is a spherical surface. That is, the projection-side concave mirror 6 is a spherical mirror. The mirror surface 61 of the projection-side concave mirror 6 is not necessarily spherical, and may be an aspherical surface such as an elliptical spherical surface.

  The display device 1 of the present embodiment is arranged so that the optical axis of light emitted from the display device 1 is in the X-axis direction. Further, the display device 1 of the present embodiment is located on the projection side beam splitter 5 side (observation point 8 side, right side in FIG. 5) from the center point 32 of the concave mirror 3 in the X-axis direction. Thereby, since the display apparatus 1 does not protrude from the center point 32 of the concave mirror 3 in the X-axis direction, it is possible to keep the apparatus thin in the X-axis direction. Note that description of functions similar to those of the display device 1 (see FIG. 1) of the first embodiment is omitted.

  In the optotype presenting apparatus according to the present embodiment, as shown in FIG. 6, the projection-side concave mirror 6 is arranged so that the height L1 from the lowest position of the concave mirror 3 can move between 220 mm and 263 mm. The length L2 in the axial direction is 160 mm, and the length L3 in the Z-axis direction is 120 mm. In the X-axis direction, the distance L4 between the beam splitter 2 (point 22) and the concave mirror 3 (center point 32) is 100 mm, and the distance L5 between the beam splitter 2 (point 22) and the observation point 8 is 100 mm. It is. Said height L1, length L2, L3 and distance L4, L5 are examples, and are not limited to said value, It sets suitably according to a use.

  When the optical distance between the display device 1 and the concave mirror 3 is increased in order to form a virtual image of the display image at a distant place (for example, the viewing distance is 5.0 m), the height of the visual target presenting device according to the present embodiment is increased. L1 is lower than the height L1 (see FIG. 3) of the optotype presenting apparatus according to the first embodiment.

  As shown in FIG. 7, the virtual image (solid line in FIG. 7) of the display image (observation target) of the present embodiment is a case where the split surface 941 of the beam splitter 94 as shown in FIG. 14 is a plane (solid line in FIG. 15). Compared to (see), distortion is reduced. 7 shows, as an example of the present embodiment, the radius of curvature of the split surface 21 of the beam splitter 2 is 800 mm, the conic constant k is 0.0, the radius of curvature of the mirror surface 31 of the concave mirror 3 is 650 mm, and the conic constant k. Is a distortion grating of a virtual image when −0.6, the radius of curvature of the mirror surface 61 of the projection-side concave mirror 6 is 370 mm, and the conic constant k is 0.0. FIG. 7A shows a case where the viewing distance is 1.0 m, and FIG. 7B shows a case where the viewing distance is 5.0 m. The radius of curvature and the conic constant k of the beam splitter 2, the concave mirror 3, and the projection-side concave mirror 6 are not limited to the above values, and are appropriately set according to the application. The broken lines in FIGS. 7 and 15 indicate display images.

  The optotype presenting apparatus of this embodiment can move the projection-side concave mirror 6 by the moving device 4. Thereby, the movement apparatus 4 of this embodiment can change the optical distance between a display image (observation object) and the projection side concave mirror 6. FIG. That is, the moving device 4 of this embodiment has a function of a projection side distance adjusting unit. The moving device 4 of this embodiment can move the projection-side concave mirror 6 by, for example, a method of holding the projection-side concave mirror 6 in place of the display device 1 on the holding plate 41 of the first embodiment. Is not limited.

  As described above, according to the optotype presenting apparatus of the present embodiment, the optical path direction of the light emitted from the display device 1 can be changed on the way by the projection side beam splitter 5 and the projection side concave mirror 6. This prevents the entire projection unit (display device 1, projection-side beam splitter 5, projection-side concave mirror 6) from extending in one direction compared to the case of direct projection from the display device 1 to the beam splitter 2. The height of the sign presentation device can be reduced. This is particularly effective when a virtual image of the display image is formed at a distant position by increasing the optical distance between the display image (observation target) and the concave mirror 3.

  Moreover, according to the optotype presenting apparatus of the present embodiment, the moving device 4 changes the optical distance between the display device 1 and the projection-side concave mirror 6 to change the eye focus adjustment function unconsciously. As a result, the eye strain of the observer can be further reduced.

(Embodiment 3)
The optotype presenting apparatus according to the third embodiment is provided with a prism-type beam splitter 7 as shown in FIG. 8 in place of the non-planar plate-like beam splitter 2, and the optotype presenting apparatus according to the first embodiment. (See FIG. 1). In addition, about the component similar to the optotype presenting apparatus of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The beam splitter 7 of the present embodiment includes an incident surface 71 on which light emitted from the display surface 11 of the display device 1 is incident, and a dividing surface 72 that divides light incident from the incident surface 71 into reflected light and transmitted light. And a back surface 73 to which the concave mirror 3 is attached. The beam splitter 7 is made of, for example, optical glass or plastic. A dielectric multilayer film is formed on the dividing surface 72.

  The concave mirror 3 of the present embodiment is a reflective layer and is formed directly on the back surface 73 of the beam splitter 7. The reflected light divided by the division surface 72 of the beam splitter 7 is projected onto the reflection layer (concave mirror 3), whereby a virtual image of a display image (observation target) is formed. In addition, description is abbreviate | omitted about the function similar to the concave mirror 3 (refer FIG. 1) of Embodiment 1. FIG.

  The optotype presenting apparatus according to the present embodiment can increase the component strength by employing the prism-type beam splitter 7 as described above as compared with the case where the non-planar plate-shaped beam splitter 2 is employed. Making it easy.

  Note that the beam splitter 7 of the present embodiment may be applied to the optotype presenting apparatus of the second embodiment.

(Embodiment 4)
The optotype presenting apparatus according to the fourth embodiment is different from the optotype presenting apparatus according to the first embodiment (see FIG. 1) in that the concave mirror 3 is inclined to the beam splitter 2 side as shown in FIG. Is different. In addition, about the component similar to the optotype presenting apparatus of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The beam splitter 2 of the present embodiment is arranged so that an angle θ1 formed by the tangential plane 23 of the point 22 on the dividing plane 21 and the optical axis of the display device 1 is 45 °. A point 22 on the dividing surface 21 is a point where the reflected light 24 projected on the center point 32 of the mirror surface 31 of the concave mirror 3 is generated. Note that a description of the same functions as those of the beam splitter 2 (see FIG. 1) of the first embodiment will be omitted.

  The concave mirror 3 of the present embodiment is disposed so as to be inclined so that the upper side (display device 1 side) is on the beam splitter 2 side (right side in FIG. 9) with respect to the lower side. In addition, description is abbreviate | omitted about the function similar to the concave mirror 3 (refer FIG. 1) of Embodiment 1. FIG.

  As described above, in the optotype presenting apparatus according to the present embodiment, the concave mirror 3 is arranged to be inclined to the beam splitter 2 side, thereby reducing the width W1 of the apparatus compared to the width W2 of the conventional optotype presenting apparatus. be able to. That is, the optotype presenting apparatus according to the present embodiment presents the conventional optotype presenting while presenting a virtual image farther away from the display image (observation target) as an optotype without worrying about the distortion of the optotype to the observer. The width W1 of the device can be made thinner than the width W2 of the device (broken line in FIG. 9).

  In addition, the configuration in which the concave mirror 3 is inclined to the beam splitter 2 side as in the present embodiment may be applied to the visual target presenting apparatus according to the second and third embodiments.

(Embodiment 5)
The optotype presenting apparatus according to the fifth embodiment is different from the optotype presenting apparatus according to the first embodiment (see FIG. 1) in that the display device 1 is inclined toward the concave mirror 3 as shown in FIG. In addition, about the component similar to the optotype presenting apparatus of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The display device 1 of the present embodiment is disposed so as to be inclined such that the concave mirror 3 side (left side in FIG. 10) is lower than the opposite side (right side in FIG. 10). Note that description of functions similar to those of the display device 1 (see FIG. 1) of the first embodiment is omitted.

  The beam splitter 2 of the present embodiment is arranged such that an angle θ1 formed by the tangent plane 23 of the point 22 on the dividing surface 21 and the optical axis of the display device 1 is greater than 45 °. A point 22 on the dividing surface 21 is a point where the reflected light 24 projected on the center point 32 of the mirror surface 31 of the concave mirror 3 is generated. Note that a description of the same functions as those of the beam splitter 2 (see FIG. 1) of the first embodiment will be omitted.

  According to the optotype presenting apparatus of the present embodiment, the conventional optotype is presented while presenting a virtual image farther away from the display image (observation target) as the optotype without worrying about the distortion of the optotype to the observer. The width W1 of the device can be made thinner than the width W2 of the presenting device (broken line in FIG. 10).

  In addition, you may apply the structure which the display apparatus 1 inclines to the concave mirror 3 side like this embodiment to the optotype presenting apparatus of Embodiment 3. FIG.

(Embodiment 6)
The optotype presenting apparatus according to the sixth embodiment is different from the optotype presenting apparatus according to the first embodiment (see FIG. 1) in that the real image 81 of the observation target (display image) is presented as a target as shown in FIG. Is different. In addition, about the component similar to the optotype presenting apparatus of Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 11, the splitting surface 21a of the beam splitter 2a of the present embodiment reduces the distortion of the real image 81 of the display image formed by the concave mirror 3 as compared with the case where the splitting surface is a plane. The spherical surface is convex to the opposite side of the concave mirror 3. The dividing surface 21a may be a non-planar surface other than the spherical surface as described above as long as the distortion of the real image 81 of the display image can be reduced. Description of functions similar to those of the beam splitter 2 (see FIG. 1) of the first embodiment is omitted.

  The beam splitter 2 a is arranged as described above with respect to the concave mirror 3, and the angle θ <b> 1 formed by the tangent plane 23 of the point 22 on the dividing surface 21 a and the optical axis of the display device 1 with respect to the display device 1. Is arranged to be less than 45 °.

  In the optotype presenting apparatus of the present embodiment, as shown in FIG. 12, the display device 1 is arranged so that the height L1 from the lowest position of the concave mirror 3 can move between 176 mm and 178 mm, and the Y axis of the concave mirror 3 The length L2 in the direction is 160 mm, and the length L3 in the Z-axis direction is 120 mm. In the X-axis direction, the distance L4 between the beam splitter 2a (point 22) and the concave mirror 3 (center point 32) is 50 mm, and the distance L6 between the concave mirror 3 (center point 32) and the observation point 8 is 800 mm. It is. In addition, said height L1, length L2, L3 and distance L4, L6 are examples, and are not limited to said value, It sets suitably according to a use.

  Thereby, the optotype presenting apparatus according to the present embodiment has the concave mirror 3 such that the optical distance between the virtual image (second virtual image) formed by the beam splitter 2 a and the concave mirror 3 is longer than the focal length of the concave mirror 3. And the real image 81 of the display image can be used as a visual target.

  As shown in FIG. 13, the real image (solid line in FIG. 13) of the display image (observation target) in the optotype presenting apparatus according to the present embodiment is a case where the dividing plane 941 of the beam splitter 94 as shown in FIG. Compared to (see the solid line in FIG. 15), distortion is reduced. The beam splitter 94 shown in FIG. 14 rises in a direction (left side in FIG. 14) facing the mirror surface 31 of the concave mirror 3 as compared with the half mirror 92. The beam splitter 94 divides the light emitted from the display device 91 into reflected light and transmitted light by a flat dividing surface 941. FIG. 13 shows, as an example of this embodiment, the radius of curvature of the split surface 21a of the beam splitter 2a is 5000 mm, the conic constant k is −50.0, the radius of curvature of the mirror surface 31 of the concave mirror 3 is 250 mm, and the conic constant. The distortion grating of the real image when k is −0.78 is shown. FIG. 13A shows a case where the viewing distance L7 is 400 mm, and FIG. 13B shows a case where the viewing distance L7 is 410 mm. The curvature radii and the conic constant k of the beam splitter 2a and the concave mirror 3 are not limited to the above values, and are appropriately set according to the application. The broken lines in FIGS. 13 and 16 indicate display images.

  As described above, even when the target is the real image 81, the split image 21a of the beam splitter 2a is non-planar (spherical), so that the real image is compared with the case of the beam splitter 94 having the flat split surface 941. Distortion can be reduced.

  From the above description, even when the real image 81 of the display image is presented as a visual target as in the visual target presenting apparatus of the present embodiment, the width W1 of the apparatus is reduced without increasing the distortion of the visual target. be able to. That is, the optotype presenting apparatus according to the present embodiment presents the conventional optotype presenting apparatus (showing the real image 81 closer to the display image as an optotype without worrying about the distortion of the optotype to the observer). Compared with the width W2 of the broken line in FIG. 11, the width W1 of the device can be reduced.

  In addition, you may apply the structure for making the real image 81 of a display image into a visual target like this embodiment to the visual target presentation apparatus of Embodiment 2-5.

  The observation target of each embodiment may be, for example, a planar object instead of the display image displayed on the display device 1. When the observation target is an object, the object can be moved by being directly or indirectly attached to the holding plate 41. Even when the observation target is an object, the optotype presenting apparatus presents a virtual image farther away from the object (observation target) as a target without worrying about the distortion of the target. The width of the device can be made thinner than the width of the optotype presenting device.

  By the way, as means for changing the optical distance between the display device 1 and the concave mirror 3, the means for moving only the display device 1, the means for moving only the concave mirror 3, and both the display device 1 and the concave mirror 3 are moved. There is a means to make it. By moving only the display device 1, the optical distance between the display device 1 and the beam splitter 2 (2a) can be changed. By moving only the concave mirror 3, the optical distance between the beam splitter 2 (2a) and the concave mirror 3 can be changed. The display device 1 and the concave mirror 3 can be moved using, for example, an actuator.

  Therefore, as a modification of each embodiment, the optotype presenting apparatus may include a concave mirror moving device that moves the concave mirror 3 as the distance adjustment unit instead of the moving device 4 or together with the moving device 4. The optotype presenting apparatus according to the modified example can move the virtual image or the real image by moving the concave mirror 3. However, in order for the observer to correctly observe the virtual image or the real image, the position of the eye of the observer with respect to the concave mirror 3 is limited to a certain range. For this reason, when moving the concave mirror 3, it is necessary to move the position of an observer's eyes.

  Therefore, among the three means for changing the optical distance between the display device 1 and the concave mirror 3, the means for moving only the display device 1 is the best. That is, as the distance adjusting unit, the moving device 4 of each embodiment is superior to the concave mirror moving device in that it is not necessary to move the position of the observer's eyes.

  In the second embodiment, means for changing the optical distance between the display device 1 and the projection-side concave mirror 6 include means for moving the display device 1 and means for moving the projection-side concave mirror 6. By moving the display device 1, the optical distance between the display device 1 and the projection-side beam splitter 5 can be changed. By moving the projection-side concave mirror 6, the optical distance between the projection-side beam splitter 5 and the projection-side concave mirror 6 can be changed.

  As another example of the use of the target presentation device, a target presentation device is provided separately from the device for VDT work. When the VDT work continues for a certain period of time or the eyes are tired, A presentation device may be used.

  Moreover, you may use the optotype presenting apparatus of each embodiment for an image display system. Examples of the image display system include a television receiver and a projector. For example, the image display system is embedded in a space between walls of a building. The display image (observation target) displayed on the display device 1 may be a television program or a playback image from a playback device. According to the image display system as described above, by embedding the image display system in the space inside the wall, the living space can be widened and the interior property can be improved. The image display system may be installed in a space behind the ceiling.

  Furthermore, you may use the optotype presenting apparatus of each embodiment for a vehicle-mounted display apparatus. As an in-vehicle display device, for example, there is an instrument panel or a display unit of a navigation system.

1 Display device (projection unit, light source)
2, 2a, 7 Beam splitter 21, 21a, 71 Dividing surface 3 Concave mirror 31 Mirror surface 32 Center point 33 Normal 4 Moving device (distance adjustment unit, projection side distance adjustment unit)
5 Projection-side beam splitter 6 Projection-side concave mirror

Claims (9)

An optotype presenting apparatus that presents an image of an observation target as an optotype to an observer,
A projection unit for projecting the observation target;
A beam splitter having a splitting surface for splitting light emitted from the projection unit into reflected light and transmitted light;
A concave mirror having a mirror surface on which the reflected light is projected and forming the image,
The beam splitter and the concave mirror are arranged so that the reflected light projected onto the center point of the mirror surface is inclined toward the projection unit with respect to the normal line at the center point,
The optotype presenting apparatus, wherein the splitting surface of the beam splitter is formed to be non-planar.   The optotype presenting apparatus according to claim 1, wherein the image is a virtual image.   3. The optotype presenting apparatus according to claim 1, wherein the splitting surface of the beam splitter is formed to be convex toward the concave mirror.   The optotype presenting apparatus according to claim 1, wherein the image is a real image.   5. The optotype presenting apparatus according to claim 1, wherein the splitting surface of the beam splitter is formed to be convex toward the side opposite to the concave mirror.   The optotype presenting apparatus according to claim 1, wherein the mirror surface of the concave mirror is formed as an aspherical surface.   The optotype presenting apparatus according to claim 1, further comprising a distance adjusting unit that changes an optical distance between the observation target and the concave mirror. The projection unit is
A light source that emits light for projecting the observation target;
A projection-side beam splitter that splits the light emitted from the light source into reflected light and transmitted light;
The target presentation apparatus according to claim 1, further comprising: a projection-side concave mirror that reflects the reflected light divided by the projection-side beam splitter toward the beam splitter.   The optotype presenting apparatus according to claim 8, further comprising a projection-side distance adjusting unit that changes an optical distance between the light source and the projection-side concave mirror.

Images