JP4503484B2 - Space floating image display device - Google Patents

Description

  The present invention relates to a space floating image display device, and more particularly to a technique effective when applied to a display device that floats a three-dimensional image in an external space of a display means for displaying an image.

  Conventionally, as a display device that displays an image of an object or the like, there is a display device that floats and displays (presents) an image displayed on the display unit in an external space of a display unit (display surface) that displays the image. . Such a display device is applied to, for example, a touch panel display device.

  The touch panel display device is, for example, a display device in which a flat switch called a touch panel is overlaid on a display means such as a liquid crystal display. When viewed from an observer, an image such as a menu button displayed on the display means, The depth position of the touch panel that the observer touches with a finger, an input pen, or the like is different, and the user may feel uncomfortable. Therefore, the feeling of discomfort can be reduced by displaying (presenting) an image such as a menu button displayed on the display means while floating near the touch panel.

  Examples of the display device that floats and displays (presents) the image displayed on the display means include a display device that displays a three-dimensional image (stereoscopic image) of an object. As such a display device, for example, a stereoscopic display device (for example, refer to Patent Document 1) using a fixed focus lens and a refractive index variable substance, or a three-dimensional display device called DFD (for example, Patent Document 2). See.) Is known.

  The stereoscopic display device described in Patent Document 1 is a device that stereoscopically displays a two-dimensional image displayed on the display means, and the difference in dielectric constant when a voltage of the first frequency is applied is positive. A layer of a refractive index variable material having two or more different dielectric constants, wherein the difference between the dielectric constants when the voltage of the second frequency is applied becomes a negative value, and a fixed focus lens having a predetermined focal length And an imaging position shift that moves the imaging position of the two-dimensional image displayed on the display means, comprising at least a pair of transparent electrodes that sandwich a layer made of the fixed focus lens and the refractive index variable substance. Means, a synchronizing means for synchronizing the update cycle of the two-dimensional image displayed on the display means and the moving period of the imaging position of the imaging position moving means, and the different first based on the synchronizing means Frequency and said second frequency Wherein the driving output consisting of a three-dimensional display apparatus comprising a drive means for driving the imaging position moving means. In other words, the stereoscopic display device described in Patent Document 1 synchronizes the change in the refractive index of the refractive index variable substance with the switching period of the two-dimensional image, so that the fixed focus lens, the refractive index variable substance, This is a device that displays (presents) a three-dimensional image by changing the focal length of the layer consisting of the above, displaying a plurality of floating images with different depth positions as viewed from the observer. Therefore, in order to display the three-dimensional image, display means having a high image display switching speed (response speed) is required, and the dielectric constant of the refractive index variable substance is synchronized with the image switching. Each of the above means for changing is necessary.

  Further, in the stereoscopic display device described in Patent Document 1, increasing the resolution of a high-speed display element is not only difficult to manufacture, but the amount of information to be supplied to the device during driving becomes enormous. It is not realistic. Therefore, for example, there is a problem that it is difficult to apply to a display device including a touch panel that performs display that requires high definition such as character information.

In addition, the DFD described in Patent Document 2 is a two-dimensional image obtained by projecting a display target object from a plurality of display surfaces at different depth positions as viewed from the observer from the viewing direction of the observer. The generated two-dimensional image is displayed on each of a plurality of display surfaces at different depth positions as viewed from the observer, and the brightness of the displayed two-dimensional image is independent for each display surface. This is a device that generates a three-dimensional stereoscopic image by changing the distance to. Such a DFD is a ratio of the luminance of the image displayed on the front display surface (display means) viewed from the observer and the luminance of the image displayed on the back display surface viewed from the observer. By changing the display device, the display device appears to display the image at a position corresponding to the luminance ratio of the image between the display surfaces. That is, in the DFD, the generated three-dimensional stereoscopic image is limited between the display surfaces for displaying the two-dimensional image. Therefore, for example, when a 3D image stereoscopic image is displayed in the external space of the display surface (near the touch panel) like the touch panel display device, there is a problem that it cannot be applied as it is.
Japanese Patent No. 3310157 Japanese Patent No. 3460671

  The problem to be solved by the present invention is that, as described in the background art, in the case of the stereoscopic display device described in Patent Document 1, the device becomes large and the application range is narrow. .

  As another problem, in the case of the three-dimensional display device (DFD) as described in Patent Document 2, the generated three-dimensional stereoscopic image is limited between the display surfaces and is the entire display surface. There is also a point that a three-dimensional stereoscopic image cannot be generated in the external space of the display means.

  An object of the present invention is to provide a technique capable of simplifying and downsizing a stereoscopic display device that displays a floating image in an external space of a display unit.

  Another object of the present invention is to provide a technique capable of floating and displaying the entire three-dimensional stereoscopic image even when a three-dimensional stereoscopic image is displayed by a display means.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The outline of the invention disclosed in the present application will be described as follows.

Display means for displaying an image of an object, and image floating means for floating an image displayed on the display means in an external space of the display means. The image floating means is independent of the distance from the display means. A space-floating image display device comprising an equal-magnification imaging optical system that forms an erect image or an inverted image with the same magnification as the image displayed on the display means in an external space of the display means,
The equal-magnification imaging optical system includes n + 1 lenses (n is an integer equal to or greater than 1) having a focal length of f ₁ and n lenses having a focal length of f ₂ , and the focal length is Either the f ₁ lens or the focal length f ₂ lens, or both, is a variable focus lens;
Wherein the focal length is the focal length of the lens f ₁ is f ₂ lenses are arranged alternately, and are arranged at equal intervals, the distance d between two of the adjacent lenses is, k number of In the recurrence formulas represented by the following formulas (5) to (8) when M _k is the magnification of image formation of light passing through the lens, M _{k = 2n + 1} = 1 or −1 is satisfied, and , A space floating image display device having a value independent of L ₀ .

Space floating image display device of the present invention, as before mentioned, with the like Baiyuizo optical system, an image that is actually displayed on the display unit, regardless of the distance from the display means, An image is formed in an external space of the display means. Therefore, even if the display unit is a display unit that displays a three-dimensional stereoscopic image between a plurality of display surfaces, for example, DFD, the entire three-dimensional stereoscopic image can be formed (floating). it can.

The structure of the like Baiyuizo optical system, various configurations may be used, as described above, the lens of the n + 1 sheets focal length is f ₁ (n is an integer of 1 or more), the focal distance f it is desirable to n lenses is ₂ is an optical system arranged alternately. At this time, these lenses are arranged at equal intervals, and the interval d between two adjacent lenses is, as described above, the recurrence formula expressed by the equations (5) to (8). A value that satisfies M _{k = 2n + 1} = 1 or −1 and does not depend on L ₀ is used. In this way, the interval when the focal length to the lens n + 1 laminated in f _1, for example, the interval at which the focal length lens was n + 1 stacked in equal magnification imaging optical system consisting only of lenses f ₁ The display device can be further reduced in size.

  At this time, if a variable focus lens is used as the lens, a wide depth range can be expressed even when the depth display range that can be displayed by the three-dimensional display device is narrow.

  In the space floating image display device of the present invention, the display means may be any means as long as it can actually display an image of an object or the like. That is, the display means may be a two-dimensional display device that displays a two-dimensional image such as a general liquid crystal display or a plasma display, or a three-dimensional stereoscopic image such as a DFD or a volume scanning display device. It may be a three-dimensional display device capable of displaying.

In addition, when using an equal magnification imaging optical system in which a plurality of lenses are arranged at a predetermined interval as in the space floating image display device of the present invention, the image displayed on the display means can be floated as it is. it can. Therefore, as the display means, for example, by using a three-dimensional display apparatus such as the DFD, without that such switch the images at high speed on the display means as the stereoscopic display device described in Patent Document 1 May be.

Hereinafter, the present invention will be described in detail together with embodiments (examples) with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same function are given the same reference numerals and their repeated explanation is omitted.

  1 and 2 are schematic views showing the principle of the space floating image display device of the present invention. FIG. 1 is a diagram in the case of floating an equal-size erect image, and FIG. FIG.

  As shown in FIGS. 1 and 2, the space floating image display device of the present invention includes a display unit 1A that actually displays an image of an object, etc., and an image displayed on the display unit 1A. It is composed of a 1 × imaging optical system 2 that forms an image in the external space at an equal magnification. At this time, the image formation by the equal-magnification imaging optical system 2 may be an erect image 1B as shown in FIG. 1 or an inverted image 1C as shown in FIG. As described above, when the image displayed on the display unit 1A is imaged at an equal magnification in the external space of the display unit 1A by using the equal-magnification imaging optical system 2, the observer 3 becomes the imaging unit 1B. , 1C, it can be perceived as if the image displayed on the display means 1A exists.

(Reference Example 1)
FIG. 3 is a schematic diagram showing a schematic configuration of the space floating image display device of Reference Example 1 according to the present invention.
In FIG. 3, 1A is a display means, 1B and 1C are images, 2 is an equal-magnification imaging optical system, and 201 _h (h = 1, 2, 3,..., N) is a lens having a focal length f.

For example, as shown in FIG. 3, the space floating image display device of Reference Example 1 has n lenses (n is 2 or more) having the same focal length (f) as the display means 1A that actually displays the floating image. ) 201 _h (h = 1, 2, 3,..., N) is composed of the equal-magnification imaging optical system 2 arranged at equal intervals with the interval d1.

When the n lenses 201 _h having the same focal length are arranged at equal intervals as in the equal magnification imaging optical system 2 used in the space floating image display apparatus of Reference Example 1, the focal length is f, When the interval is d, the magnification M _k for image formation up to the k-th lens is expressed by a recurrence formula as shown in the following formulas (1) to (4).

When imaging the erect 1B equal magnification using the n lenses 201 _h as magnification imaging optical system 2 of Reference Example 1 is a M k _{= n = 1.} Therefore, the distance d1 of the lens 201 _h can be obtained by obtaining d satisfying M _{k = n} = 1 using the equations (1) to (4). When an inverted image 1C having the same magnification is formed, M _{k = n} = −1. Therefore, the distance d1 of the lens 201 _h is obtained by obtaining d satisfying M _{k = n} = −1 using the equations (1) to (4).

Here, as an example of a method for obtaining the lens 201 _h distance d1, like a case where the focal length overlapped two sheets of lens ₂₀₁ 1, 201 ₂ f, briefly described how to solve the recurrence formula.

FIG. 4 is a schematic diagram for explaining how to obtain the lens interval in the equal-magnification laminated optical system of Reference Example 1.

It is assumed that the _two lenses 201 ₁ and 201 ₂ having a focal length f are arranged at an interval d _k−1 = d ₁ as shown in FIG. At this time, the distance from the first sheet of the lens 201 ₁ to an object (display means 1A) and -L _0, the magnification of the imaging 1D from the first sheet of the lens 201 ₁ according to the first sheet of the lens 201 _{1 M 1} , the distance to the imaging 1D and _{L 1,} the magnification of the imaging 1B by up to the second sheet of lenses 201 _{2 M 2,} the distance to the imaging 1B and _{L 2.} At this time, the L ₂ is represented by the following formula (9) from the formula (3) and the formula (4), and the M ₂ is represented by the following formula (10) from the formula (1) and the formula (9). The

In the mathematical formula (9) and the mathematical formula (10), the L ₁ is represented by the following mathematical formula (11) from the mathematical formula (3) and the mathematical formula (4), and the M ₁ is represented by the mathematical formula (1) and the mathematical formula ( 11) to the following formula (12).

When L ₁ represented by the mathematical formula (11) and M ₁ represented by the mathematical formula (12) are substituted into the mathematical formula (10), M ₂ is represented by the following mathematical formula (13).

When the equation (13) obtained in this way is solved for d with M ₂ = 1, d becomes the following equation (14).

However, in this case, as shown in the equation (14), d depends on the distance −L ₀ from the _first lens 2011 to the display unit 1A. Therefore, for example, the display unit 1A is made up of one of the display surface, such as when to intact floating one two-dimensional image displayed on the display surface, to the display surface from the lens 201 ₁ of the first sheet By stacking the lenses at an interval d based on the distance −L ₀ , a two-dimensional image displayed on the display surface can be formed. However, when the display unit 1A is a device that displays a three-dimensional stereoscopic image such as a DFD, for example, the L ₀ is different at each point of the three-dimensional stereoscopic image. The lens interval d1 = d cannot be determined. Therefore, d obtained by the mathematical formula (14) is not suitable as a solution.

On the other hand, when Equation (14) is solved for d with M ₂ = −1, d becomes Equation (15) below.

In this case, d does not depend on the distance −L ₀ from the _first lens 2011 to the display unit 1A. Therefore, if the distance between the two lenses is d1 = 2f, any distance from the _first lens 2011 can be arbitrarily set. It is possible to form an image of the display means 1A at a distance of 1 as an inverted image 1C of the same magnification.

When n = 3 or more, that is, when three or more lenses are stacked, the recurrence formula is solved by the same procedure, and d which does not depend on the distance from the first lens to the object −L ₀ is obtained. For example, by arranging the lenses at intervals of the values, it is possible to form an equal-magnification erect image or an inverted image. At this time, although a detailed calculation procedure is omitted, in the case of n = 2 to 8 using the above recurrence formula, an inverted image that is the same as the lens interval d1 when an erect image of the same magnification is formed. When the value of the lens interval d1 in the case of forming an image is obtained, it is as shown in Table 1 below.

5 and 6 are schematic diagrams showing a specific example of the space floating image display apparatus of Reference Example 1. FIG. 5 is a diagram for explaining the principle of DFD used as display means, and FIG. 6 shows DFD as display means. It is a figure explaining the structural example and operation | movement of an apparatus at the time of using.

As described above, the equal-magnification imaging optical system used in the spatial floating image display apparatus of Reference Example 1 includes n lenses 201 _h (h = 1, 2, 3,..., N) having the same focal length. In the recurrence formulas expressed by the formulas (1) to (4), M _n = 1 or −1, and the distance between the display unit 1A and the lens 201 ₁ closest to the display unit 1A− by placing at distance d1 that does not depend on L _0, to image the erected 1B or inverted image 1C of the equivalent magnification of the image displayed on the display unit 1A to the outer space of the display unit 1A. Therefore, in the space floating image display device of Reference Example 1, for example, a three-dimensional display device such as DFD can be used as the display unit 1A.

For example, as shown in FIG. 5, the DFD is a display unit arranged such that _two display surfaces ₁ </ _b > A ₁ and 1 </ _b > A ₂ overlap in the depth direction when viewed from the viewpoint P of the viewer 3, such as an object. When the above image is displayed, a two-dimensional image obtained by projecting the display target object from the viewpoint direction of the observer is generated and displayed on each of the display surfaces 1A ₁ and 1A ₂ . At this time, the luminance of the two-dimensional image Obj ₁ displayed on the front display surface 1A ₁ as viewed from the observer is γ ₁ , and the luminance of the two-dimensional image Obj ₂ displayed on the back display surface 1A ₂ is γ _2. Then, from the observer's viewpoint P, it is between the display surfaces 1A ₁ and 1A ₂ and is a distance H1 from the front display surface 1A ₁ and a distance H2 from the back display surface 1A _2. It appears that the image Obj of the object is displayed at a depth position where the ratio H1: H2 is γ ₂ : γ ₁ . Therefore, for example, the display object can be displayed (presented) three-dimensionally by changing the luminance ratio γ ₁ : γ ₂ of each pixel that displays each point on the display object.

When using the DFD as the display unit 1A spatial floating image display device of Reference Example 1, for example, as shown in FIG. 6, the like to further front of the display surface 1A ₁ in front as seen from the observer Baiyuizo The optical system 2 is disposed. At this time, for example, as shown in FIG. 6, the equal-magnification imaging optical system 2 laminates four lenses 201 _h (h = 1, 2, 3, 4) having the same focal length. . When four lenses are stacked, as shown in Table 1, both an erect image and an inverted image can be formed, but the interval between the lenses can be narrowed when an inverted image is formed. . Therefore, the like Baiyuizo optical system 2, and an optical system for forming an inverted image of the equal magnification by laminating four lenses 201 _h, and the focal length f of the lens 201 _h and 77 mm, the lens The spacing is about 46 mm. At this time, as described above, the distance between the lenses does not depend on the distance −L ₀ between the display unit 1A and the lens 2011 ₁ closest to the display unit 1A, as shown in FIG. In addition, even when there are _two display surfaces 1A ₁ and 1A ₂ having different distances from the lens closest to the display means 1A, an inverted image of the same magnification of each display surface 1A ₁ and 1A ₂ can be formed. it can.

In this way, the display having the same magnification imaging optical system 2 in which the four lenses 201 _h having a focal length f of 77 mm are arranged at an interval of 46 mm and the two display surfaces 1A ₁ and 1A ₂ are stacked with a surface spacing of 5 mm. means were arranged to substantially close contact with the display surface 1A ₁ in front of (DFD) (front), the display of the front at about 20mm from the farthest lens (right end of the lens 201 ₄₎ from the DFD surface 1A ₁ an inverted image 1C ₁ is imaged, that inverted image 1C ₂ of the display surface 1A ₂ of the rear face is focused at the position of about 15 mm, the inventors of the present invention were confirmed by experiments.

At this time, in the space floating image display device, the inverted images 1C ₁ and 1C ₂ having the same magnification as the images displayed on the display surfaces 1A ₁ and 1A ₂ of the DFD are floated and displayed in the external space of the DFD. By viewing the inverted images 1C ₁ and 1C ₂ , the same visual effect as when viewing the DFD directly can be obtained. Therefore, a three-dimensional stereoscopic image can be displayed in the external space of the DFD using the DFD. At this time, if a touch panel (not shown) is provided in the vicinity of the positions where the inverted images 1C ₁ and 1C _{2 on the} front and rear display surfaces are formed, an image (an inverted image) formed in the vicinity of the touch panel is provided. The touch panel can be operated while viewing the screen.

  At this time, in the example shown in FIG. 6, a case is described in which a DFD that displays a three-dimensional stereoscopic image of an object using two display surfaces is used. However, three or more display surfaces are used. It may be a DFD. The display means is not limited to the DFD as long as it is a means for displaying a three-dimensional stereoscopic image. For example, the display means may be a three-dimensional display device such as a volume scanning display device.

  Further, the number of lenses to be stacked is not limited to four as shown in FIG. 6, and may be two or more as shown in Table 1, for example. However, when the number of lenses is small, the viewing angle becomes narrow. In addition, when the number of lenses is large, the viewing angle is widened, but the image is deteriorated due to absorption loss or scattering of the lens. For these reasons, it is preferable that the number of laminated lenses is about 4 to 8.

  In addition, various lenses such as a variable focus lens such as a bulk lens, a Fresnel lens, and a liquid crystal lens can be used as the lens, but it is preferable to use a Fresnel lens from the viewpoint of reducing the thickness.

  In addition, various optical materials such as acrylic, polycarbonate, and glass can be used as the material of the lens, but it is preferable to use acrylic from the viewpoints of ease of processing and high transparency.

7 to 10 are schematic diagrams for explaining an application example of the equal magnification imaging optical system used in the spatial floating image display apparatus of Reference Example 1. FIG. 7 shows the principle of the equal magnification imaging optical system. 8 is a diagram illustrating a first configuration example of an optical system that is optically equivalent to the optical system illustrated in FIG. 7, and FIG. 9 is a diagram illustrating an optical system that is optically equivalent to the optical system illustrated in FIG. FIG. 10 is a diagram illustrating a third configuration example of an optical system that is optically equivalent to the optical system illustrated in FIG.

In the space floating image display apparatus of Reference Example 1, as a 1 × magnification imaging optical system used for floating the image of the object, for example, four lenses having the same focal length (f) as shown in FIG. 201 _h (h = 1, 2, 3, 4) are laminated at equal intervals with an interval d1. At this time, the distance d1 of the lens 201 _h, if 0.6f As shown in Table 1, as shown in FIG. 7, inverted image 1C equal magnification and image displayed on the display unit 1A Can be imaged. In other words, the lens in which the light incident on the optical system from the display means 1A side is arranged at the interval d1 = 0.6f, even if it is not configured and arranged as shown in FIG. This means that an inverted image 1C having the same magnification as the image displayed on the display means 1A can be formed by exiting from the optical system after passing through the (imaging element) four times. Therefore, a configuration example of an optical system that is optically equivalent to the optical system shown in FIG. 7 and that can form an inverted image 1C having the same magnification as the image displayed on the display means 1A will be described below. .

As an optical system optically equivalent to the optical system shown in FIG. 7, for example, as shown in FIG. 8, three lenses 201 _h (h = 1, 2, 4) having the same focal length and a plane mirror are used. An optical system composed of 202 and the half mirror 203 is conceivable. At this time, the display unit 1A lens 201 ₁ of the first sheet of light incident to first pass from the side and the second sheet of lenses 201 ₂ passing the second time is spaced d1 = 0.6f. Further, the half mirror 203 is disposed between the first sheet of the lens 201 ₁ and the second sheet of lenses 201 _2. At this time, the half mirror 203, for example, the first sheet of the lens 201 ₁ from the light travels straight toward the second sheet of lens 201 _2, the second sheet of lenses 201 ₂ from the first one of the lenses 201 _The light traveling toward ₁ is arranged so that its path changes in the orthogonal direction. Then, placing the third sheet of lens 201 ₄ in the traveling direction of the light path is changed by the half mirror 203. In this case, said second sheet of lenses 201 ₂ and 3rd lens 201 _4, the spacing on the optical axis shown by a one-dot chain line in FIG. 8 is arranged such that d1.

Also, the plane mirror 202, the light having passed through the second sheet of lenses 201 ₂ is arranged to pass through the second sheet of lenses 201 ₂ again. At this time, the plane mirror 202 is disposed at a distance d1 / 2 from the _second lens 2012.

For an optical system having such a configuration, the light incident from the display means 1A side, the first sheet of lens 201 _1, the half mirror 203, passes through the second sheet of lens 201 _2, the plane mirror The light is reflected by 202 and passes through the _second lens 2012 again. Then, light passing through the second sheet of lenses 201 ₂ again, the changes the course by the half mirror 203, passes through the lens 201 ₄ of the third sheet, is emitted from the optical system.

At this time, the light incident from the display means 1A side passes through a lens having a focal length f four times before being emitted. Therefore, when the interval between the lenses ₂₀₁ h (h = 1,2,4) distance and said second sheet of lenses 201 ₂ and the plane mirror 202 as described above, the optical system and the optical shown in FIG. 7 Thus, an inverted image 1C having the same magnification as the image displayed on the display means 1A can be formed.

In the optical system shown in FIG. 8, the light path is changed using the half mirror 203. However, the present invention is not limited to this. For example, a polarizing beam splitter 204, a quarter wavelength plate 205, and a polarizing plate 206 are combined. You can also change the course of light. In this case, for example, as shown in FIG. 9, placing the polarizing beam splitter 204 instead between the lens 201 ₁ of the first sheet and the second sheet of lenses 201 ₂ of the half mirror 203, the two eye lenses 201 ₂ and disposing the quarter-wave plate 205 between the plane mirror 202. Further, for example, as shown in FIG. 9, the polarizing plate 206 is configured such that light incident from the display means 1A side becomes p-polarized light at a position optically in front of the _first lens 20111. Arrange as follows. At this time, the gap and the distance of the second sheet of lenses 201 ₂ and the plane mirror 202 of the lens ₂₀₁ h (h = 1,2,4) are the same as in the case of the optical system shown in FIG. 8 .

For an optical system having such a configuration, the light incident from the display means 1A side, the state of the p-polarized first sheet of lens 201 _1, the polarization beam splitter 204, the second sheet of lenses 201 ₂ after passing, it has become s-polarized light when the quarter wave plate 205, the flat mirror 202, again passes through the second sheet of lenses 201 ₂ by passing through in the order of the quarter-wave plate 205. Therefore, light passing through the second sheet of lenses 201 ₂ again, the route is changed by the polarization beam splitter 204, after passing through the lens 201 ₄ of the third sheet, is emitted from the optical system.

Also in this case, the light incident from the display means 1A side passes through a lens having a focal length f four times in total before being emitted. Therefore, when the interval between the lenses ₂₀₁ h (h = 1,2,4) distance and said second sheet of lenses 201 ₂ and the plane mirror 202 as described above, the optical system and the optical shown in FIG. 7 Thus, an inverted image 1C having the same magnification as the image displayed on the display means 1A can be formed.

  In the example shown in FIG. 9, the polarizing plate 206 is provided in the optical system. For example, the display unit 1A is a display including a polarizing plate, and the light from the display unit 1A is p-polarized in advance. The polarizing plate 206 is not necessary when it is in the state.

As described above, when the plane mirror 202 and the optical components such as the half mirror 203 and the polarization beam splitter 204 are used, the optical system shown in FIG. 7 with three lenses 201 _h (h = 1, 2, 4) An optically equivalent equal-magnification imaging optical system can be configured. Therefore, it can be made more compact than the optical system configured as shown in FIG.

Further, the optical system shown in FIG. 7 has four lenses 201 _h (h = 1, 2, 3, 4) laminated, but instead of the lens, an imaging effect equivalent to that of the lens is obtained. The obtained curved mirror, that is, a curved mirror having a focal length f can also be used.

As an optical system using the curved mirror, for example, as shown in FIG. 10, an optical system in which a curved mirror 207 having a focal length f instead of the _third lens 2013 is arranged. In this case, the first sheet of the lens 201 ₁ and the second sheet of the lens 201 _{and second} interval, the distance of the second sheet of lenses 201 ₂ and the curved mirror 207 on the optical axis shown by a one-dot chain line in FIG. 6 and be placed so that the distance of the curved surface mirror 207 and 4th lens 201 ₄ is respectively d1 = 0.6f, optical system and becomes optically equivalent shown in FIG. 7, displayed on the display means 1A An inverted image 1C having the same magnification as the formed image can be formed.

10 shows an example in which the curved mirror 207 is used instead of the _third lens 2013, the present invention is not limited to this, and the curved mirror may be used instead of other lenses. The curved mirror may be used in place of a single lens, a plurality of lenses, or all lenses.

  The optical system shown in FIGS. 8 to 10 is an example of an optical system optically equivalent to the optical system shown in FIG. 7. The optical system shown in FIG. 7 is not limited to these configurations and arrangements. Other configurations and arrangements may be used as long as they are optically equivalent. 8 to 9, the case where the number of lenses is four has been described. Similarly, in the case where the number of lenses is not four, any configuration and arrangement may be used as long as they are optically equivalent.

FIG. 11 is a schematic diagram for explaining an application example of the space floating image display apparatus of Reference Example 1, and is a configuration example of an apparatus that displays a stereoscopic image using a display unit including one display surface. FIG.

For example, as shown in FIG. 6, the spatial floating image display device of Reference Example 1 can only display (present) a floating image of a three-dimensional stereoscopic image displayed by a DFD in which a plurality of display surfaces are stacked. For example, a floating image of a three-dimensional stereoscopic image can be displayed (presented) by using a display unit including a single display surface.

When displaying (presenting) a floating image of a three-dimensional stereoscopic image using the display unit 1A including one display surface, for example, as shown in FIG. 11, the front surface of the DFD is displayed on the one display surface. Two-dimensional images Obj ₁ and Obj ₂ corresponding to the two-dimensional images displayed on the display surface and the rear display surface are displayed. Then, two-dimensional image Obj ₁ corresponding to the display surface of the front, as shown in FIG. 7, the first lens 201 _1, a plane mirror (total reflection mirror) 202A, a half mirror 203, the outside by the second lens 201 ₂ Form an image in space. Further, two-dimensional image Obj ₂ corresponding to the display surface of the rear surface, as shown in FIG. 7, flat mirror 202B, a third lens 201 ₁ ', the plane mirror 202C, a half mirror 203, an external space by the second lens 201 ₂ Image on top. At this time, if as the optical distance from the first lens 201 ₁ from the optical distance and the third lens 201 ₁ 'to ₂ second lens 202 to ₂ second lens 201 is respectively d = 2f, the A two-dimensional image Obj ₁ corresponding to the front display surface and an inverted image having the same magnification as the two-dimensional image Obj ₂ corresponding to the rear display surface are formed in the external space of the display means 1A.

At this time, the optical distance from the two-dimensional image Obj ₁ corresponding to the front display surface to the first lens 201 ₁ and the two-dimensional image Obj ₂ corresponding to the rear display surface to the third lens 201 _1. By changing the optical distance to ', the interval between the inverted images Obj ₁ and Obj ₂ formed in the external space of the display surface can be controlled.

As described above, according to the space floating image display device of Reference Example 1, n imaging elements (lenses) having the same focal length before the light incident on the equal magnification imaging optical system is emitted are n. In the recursion formulas expressed by the formulas (1) to (4), the imaging element is satisfied at an interval d that satisfies M _{k = n} = 1 or −1 and does not depend on L _0. By arranging the child, it is possible to form an upright image or an inverted image of the same magnification with a simple configuration.

In addition, in the space floating image display device of Reference Example 1, a display unit that cannot display a three-dimensional stereoscopic image in the external space of the display unit as it is can be used as in the DFD. It can be displayed easily.

FIG. 12 is a schematic diagram for explaining a schematic configuration of the equal-magnification imaging optical system in the space floating image display apparatus according to the first embodiment of the present invention .
In FIG. _{12, 201 h (h = 1,2} , ..., n + 1) is the focal distance is _{f 1 lens, 208 j (j = 1,2,} ..., n) is the focal length is _{f 2} lenses.

In the 1 × imaging optical system in the spatial floating image display apparatus of Reference Example 1, the imaging element is only a lens or a curved mirror having a focal length f, but the configuration of the 1 × imaging optical system is as follows. not limited to, for example, as shown in FIG. 12, n + 1 sheets of focal length _{f 1} of the lens _{201 h (h = 1,2, ...} , n + 1) and, n pieces of the focal length is _{f 2} lens 208 _j (J = 1, 2,..., N) may be alternately stacked, and the lens 201 _h having the focal length f ₁ may be arranged at equal intervals with the interval d2. The equal-magnification imaging optical system of Example 1 has such a configuration, and these 2n + 1 lenses are two adjacent lenses ( a lens 201 _h having a focal length f ₁ and a focal length f ₂ . Assume that the lenses 208 _j ) are arranged at equal intervals.

For magnification imaging optical system as shown in FIG. 12, the magnification M _k of the distance between two lenses adjacent When d (= d2 / 2), imaging by up to k-th lens Are expressed by a recurrence formula such as the following formula (5) to formula (8).

When the erect image 1B having the same magnification is formed using the equal magnification imaging optical system as shown in FIG. 12, d satisfies M _{k = 2n + 1} = 1 using the equations (5) to (8). by seeking the focal length is obtained distance d2 lens 201 _h of _{f 1.} When an inverted image 1C having the same magnification is formed, the lens having the focal length f ₁ is obtained by obtaining d satisfying M _{k = 2n + 1} = −1 using the equations (5) to (8). An interval d2 of 201 _h is obtained. The procedure for obtaining the d satisfying _{M k = 2n +} 1 = 1 or -1 the from Equation (5) using Equation (8), M _{k =} n from said equation (1) using equation (4) = Since the procedure is the same as that for obtaining d satisfying 1 or -1 , detailed description thereof is omitted.

Further, in the equal-magnification imaging optical system as shown in FIG. 12, up to n = 1, that is, a lens with a focal length f ₁ using the recurrence formulas expressed by the formulas (5) to (8). About If is two, for _example, as f 2 = -2f _1, the focal length of the time for imaging magnification of the inverted image obtaining lens 201 _1, 201 ₂ of distance d2 _{f 1,} d2 = 1 .6f. In contrast, if the lens is two in equal magnification imaging optical system focal length, such as Reference Example 1 was composed of only the lens f _1, distance d1 of the lens as shown in Table 1 It is necessary to make it 2f. In other words, between the two lenses the focal length is f _1, that the focal length sandwich the lens f _2, can be the focal length to reduce the distance of the lens f _1. Although not described, in the case of other numbers, the interval between the lenses having the focal length f ₁ can be narrowed by sandwiching the lens having the focal length f ₂ .

In other words, when the magnification-imaging optical system shown in FIG. 12, distance d2 when the focal length is laminated m sheets of lens f _1, the focal length of f ₁ lens as in Reference Example 1 It is possible to make it narrower than when only m sheets are stacked. Therefore, the equal magnification imaging optical system can be thinned.

Further, in the equal-magnification imaging optical system as shown in FIG. 12, since the focal length f ₁ and the focal length f ₂ are independent variables, the condition that satisfies M _{2n + 1} = 1 or −1 in the equation (5) is satisfied. By changing the focal length f ₁ and the focal length f ₂ , the imaging position L _{k = 2n + 1} can be freely changed. As a most typical example of this point, consider a case where n = 2, that is, the total number of lenses is five. At this time, for example, when M ₅ = −1 is solved in the equation (5), the following equation (16) is obtained as one of the solutions.

At this time, by changing f ₁ and f ₂ so as to satisfy Equation (16), it is possible to control the imaging position L ₅ while maintaining the same magnification relationship.

In the case of the equal magnification imaging optical system configured as shown in FIG. 12, it is preferable to use a variable focus lens, that is, a lens whose focal length can be changed, as the lenses 201 _h and 208 _j . An example of the variable focus lens is a liquid crystal lens.

When a variable focus lens is used as the lenses 201 _h and 208 _j , for example, in one set of optical systems, the focal length f ₁ and the focal point are satisfied under the condition that M _{2n + 1} = 1 or −1 in the formula (5). the distance f ₂ can be varied. In other words, for example, when the total number of the lenses is 5, when the lenses 201 _h (h = 1, 2, 3) having the focal length f ₁ are arranged at a certain distance d3, the lenses 201 _h , focal length _f 1, _{f 2} of 208 _j, the if they meet the equation (16) may be any combination. When the combination of the focal lengths f ₁ and f ₂ of the lenses 201 _h and 208 _j is changed, the imaging position L _{5 of the} object changes from the equation (7). Therefore, for example, even when the depth display range that can be displayed by the three-dimensional display device is narrow, a wide depth range can be expressed by changing the focal lengths f ₁ and f ₂ of the lenses 201 _h and 208 _j. it can.

In the magnification-imaging optical system shown in FIG. 12, wherein at the focal length is used concave as the lens f _2, it is not limited thereto, may be used a convex lens.

(Reference Example 2)
13 and 14 are schematic diagrams showing a schematic configuration of the space floating image display apparatus of Reference Example 2 according to the present invention, and FIG. 13 shows a configuration in the case where a paraboloid mirror is used as the equal magnification imaging optical system. FIG. 14 is a view showing an example, and FIG. 14 is a view showing a configuration example when an elliptical mirror is used as an equal magnification imaging optical system.
In FIG. 13, 209 ₁ and 209 ₂ are parabolic mirrors. In FIG. 14, reference numeral 210 denotes an elliptical mirror.

As described above, the equal magnification imaging optical system 2 in the space floating image display device of the present invention has the image actually displayed on the display means 1A (display surface) in the external space of the display means 1A at the same magnification. since it if possible be imaged is not limited to the optical system formed by laminating a reference example 1 and a plurality of lenses as described in example 1 (imaging element which transmits light), for example, a concave mirror ( An optical system using an imaging element that reflects light may be used. Therefore, in Reference Example 2, a configuration example of a space floating image display device in the case where a concave mirror is used as the above-described equal magnification imaging optical system will be described.

When a concave mirror is used as the equal magnification imaging optical system 2, for example, parabolic mirrors 209 ₁ and 209 ₂ having a parabolic inner space are used as the concave mirror, as shown in FIG. it can. At this time, the paraboloid is a mirror surface, and as shown in FIG. 13, two paraboloid mirrors 209 ₁ and 209 ₂ having the same curvature are arranged so that the open ends face each other. At this time, the two parabolic mirrors 209 ₁ and 209 ₂ are arranged so that their optical axes coincide. When the display means 1A is arranged at one focal point of the paraboloid mirror and an image is displayed, the image displayed on the display means 1A is formed at the same magnification at the other focal point of the paraboloid. be able to.

When a concave mirror is used as the equal-magnification imaging optical system 2, the concave mirror is not limited to the parabolic mirrors 209 ₁ and 209 _2. For example, as shown in FIG. An elliptical mirror 210 having a space can also be used. At this time, the spheroid surface is a mirror surface, and as shown in FIG. 14, when the display means 1A is arranged at one focal point of the spheroid surface to display an image, the spheroid surface is located at the other focal point of the spheroid surface. The image displayed on the display means 1A can be formed at the same magnification.

  As described above, even when a concave mirror is used as the equal-magnification imaging optical system, the configuration of the spatial floating image display device can be simplified as in the first embodiment.

In Reference Example 2, an example using the parabolic mirrors 209 ₁ and 209 ₂ as shown in FIG. 13 and the elliptical mirror 210 as shown in FIG. 14 is given. It is also possible to use a concave mirror having a mirror shape of

(Reference Example 3)
FIG. 15 is a schematic diagram showing a schematic configuration of the space floating image display device of Reference Example 3 according to the present invention, and is a diagram showing a configuration example when a rod-shaped lens array is used as the equal magnification imaging optical system.
In FIG. 15, reference numeral 211 denotes a rod-shaped lens.

As described above, the equal magnification imaging optical system 2 in the space floating image display device of the present invention has the image actually displayed on the display means 1A (display surface) in the external space of the display means 1A at the same magnification. As long as it is possible to form an image, in addition to the optical system in which a plurality of lenses described in Reference Example 1 and Example 1 are stacked, the optical system using the concave mirror described in Reference Example 2, for example, A rod-shaped lens array such as a Selfoc Lens Array (registered trademark of Nippon Sheet Glass Co., Ltd.) can also be used. Therefore, in Reference Example 3, a configuration example of a space floating image display device in the case where a rod-shaped lens array is used as the equal magnification imaging optical system 2 will be briefly described.

  The rod-shaped lens array is, for example, a bundle of rod-shaped lenses 211 whose refractive index continuously changes from the center toward the outer periphery, and is used as the equal-magnification imaging optical system 2. In this case, for example, as shown in FIG. 15, the rod-shaped lenses 211 are arranged so that the central axis thereof is perpendicular to the display means (display surface) 1A.

At this time, the length L _Lens of the rod-shaped lens 211 is (n−1 / 2) L _p <L _Lens <nL _p (n, where L _p is one period of light propagating through the rod-shaped lens 211. = 1, 2, 3, ...). In this manner, magnification figurine of the rod-shaped lens array Yi arranged display means at one end the image displayed on the surface (display surface) 1A is imaged at the other end of the rod-shaped lens array b.

  As described above, even when a rod-shaped lens array is used as the equal-magnification imaging optical system 2, the configuration of the spatial floating image display device can be simplified as in the first embodiment.

The present invention has been specifically described above based on the above-described embodiments and reference examples . However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Of course.

The equal-magnification imaging optical system can image an object at equal magnification. For this reason, the space floating image display device provided with the same-magnification imaging optical system is capable of displaying interiors (objects) such as bronze images, vases, sculptures, etc., in addition to the touch panel display device described in Reference Example 1. Also, the present invention can be applied to a display system that displays an advertisement displayed on a display device installed outdoors or in a public facility while floating in the space.

It is a schematic diagram which shows the principle of the space floating image display apparatus of this invention, and is a figure in the case of floating an erect image of equal magnification. It is a schematic diagram which shows the principle of the space floating image display apparatus of this invention, and is a figure in the case of floating an inverted image of equal magnification. It is a schematic diagram which shows schematic structure of the space floating image display apparatus of the reference example 1 in connection with this invention. FIG. 6 is a schematic diagram for explaining how to obtain the lens interval in the 1 × magnification optical system of Reference Example 1; It is a figure which shows one specific example of the space floating image display apparatus of the reference example 1, and is a figure explaining the principle of DFD used as a display means. It is a schematic diagram which shows one specific example of the space floating image display apparatus of the reference example 1, and is a figure explaining the structural example and operation | movement of an apparatus at the time of using DFD as a display means. It is a schematic diagram for demonstrating the application example of the equal magnification imaging optical system used for the space floating image display apparatus of the reference example 1, and is a figure which shows the principle of an equal magnification imaging optical system. FIG. 10 is a schematic diagram for explaining an application example of the equal-magnification imaging optical system used in the spatial floating image display apparatus of Reference Example 1, and is a first configuration of an optical system that is optically equivalent to the optical system shown in FIG. It is a figure which shows an example. FIG. 8 is a schematic diagram for explaining an application example of the equal-magnification imaging optical system used in the spatial floating image display apparatus of Reference Example 1, and is a second configuration of an optical system that is optically equivalent to the optical system shown in FIG. It is a figure which shows an example. FIG. 9 is a schematic diagram for explaining an application example of the equal-magnification imaging optical system used in the spatial floating image display apparatus of Reference Example 1, and a third configuration of an optical system that is optically equivalent to the optical system shown in FIG. It is a figure which shows an example. It is a schematic diagram for demonstrating the application example of the space floating image display apparatus of the reference example 1, and is a figure which shows the structural example of the apparatus which displays a three-dimensional image using the display means which consists of one display surface. . It is a schematic diagram for demonstrating schematic structure of the equal magnification imaging optical system in the space floating image display apparatus of Example 1 by this invention . It is a schematic diagram which shows schematic structure of the space floating image display apparatus of the reference example 2 in connection with this invention, and is a figure which shows the structural example at the time of using a parabolic mirror as a 1x magnification imaging optical system. It is a schematic diagram which shows schematic structure of the space floating image display apparatus of the reference example 2 in connection with this invention, and is a figure which shows the structural example at the time of using an elliptical mirror as a 1x magnification imaging optical system. It is a schematic diagram which shows schematic structure of the space floating image display apparatus of the reference example 3 in connection with this invention, and is a figure which shows the structural example at the time of using a rod-shaped lens array as an equal magnification imaging optical system.

1A ... Display unit 1A 1 _... front display surface 1A 2 _... inverted image 201 ₁ of the display surface 1B ... erected 1C ... etc magnification equivalent magnification of the rear surface (back) of the _{(front), 201 2, 201 3,} 201 n, 201 _{n + 1} ... lenses with focal length f (f ₁ ) 202, 202A, 202B, 202C ... plane mirrors (total reflection mirrors)
203 ... half mirror 204 ... polarizing beam splitter 205 ... 1/4-wave plate 206 ... polarizer 207 ... curved mirror _{208 1, 208 2, 208 3} , 208 n ... lens 209 ₁ of focal length _{f 2,} 209 2 _... release Object mirror 210 ... Elliptical mirror 211 ... Rod-shaped lens 3 ... Observer

Claims (3)

Display means for displaying an image of an object, and image floating means for floating an image displayed on the display means in an external space of the display means. The image floating means is independent of the distance from the display means. A space-floating image display device comprising an equal-magnification imaging optical system that forms an erect image or an inverted image with the same magnification as the image displayed on the display means in an external space of the display means,
Wherein such Baiyuizo optical system includes a lens of n + 1 sheets focal length is f ₁ (n is an integer of 1 or more), an n-lenses the focal length is f _2, and,
Either the lens with the focal length f ₁ or the lens with the focal length f ₂ , or both are variable focus lenses,
Wherein the focal length is the focal length of the lens f ₁ is f ₂ lenses are arranged alternately, and are arranged at equal intervals,
The distance d between the two adjacent lenses is a recurrence formula expressed by the following formulas (5) to (8), where M _k is the magnification of image formation of light that has passed through the k lenses. The spatial floating image display device is characterized in that M _{k = 2n + 1} = 1 or −1 and a value that does not depend on L ₀ .

The space floating image display device according to claim 1, wherein the display unit is a two-dimensional display device that displays a two-dimensional image of an object. The space floating image display device according to claim 1, wherein the display unit is a three-dimensional display device that displays a three-dimensional stereoscopic image of an object.

Images