DISPLAY DEVICE

A display device according to one or more embodiments may be provided with: a light guide plate that guides incident light and emits the light from a light exit surface; a half mirror disposed on the light-exit-surface side of the light guide plate; and a mirror disposed on the side opposite to the light exit surface of the light guide plate. The light guide plate may form an image accompanied by a change that is made in a direction from the half mirror toward the mirror in a space different from the light exit surface.

TECHNICAL FIELD

The present invention relates to a display device that displays an image in a space.

BACKGROUND ART

Patent Literature 1 discloses a display device provided with: a transparent light guide plate on which a display unit including a plurality of recesses is formed, the recesses each having a reflecting surface that reflects incident light toward the front surface side; a half-mirror plate disposed on the front surface side of the light guide plate; and a mirror plate disposed on the back surface side of the light guide plate. The display device multiply reflects light from a light source, the light having traveled in the light guide plate and reflected on the reflecting surface of each recess, between the half-mirror plate and the mirror plate to display multiple images of the display unit.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the display device disclosed in Patent Document 1 can display only images of the display unit formed on the back surface of the light guide plate, that is, multiple images being planar images, and thus has a problem that designability is not sufficient.

An object of one aspect of the present invention is to provide a display device capable of providing a display with high taste and excellent design.

Means for Solving the Problem

In order to solve the above problem, a display device according to one aspect of the present invention is provided with: a light guide plate configured to guide incident light, reflect the light by an optical path changing unit formed at a predetermined position, and emit the light from a light exit surface; a half mirror disposed on the light-exit-surface side of the light guide plate; and a mirror disposed on a side of the light guide plate opposite to the light exit surface. The light guide plate forms an image accompanied by a change that is made in a direction from the half mirror toward the mirror in a space different from the light exit surface by light emitted from the light exit surface.

Effect of the Invention

According to one aspect of the present invention, it is possible to achieve a display device capable of providing a display with high taste and excellent design.

MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as “the embodiment”) will be described with reference to the drawings.

First, a principle of a display by the display device of the present invention will be described. In the following, for convenience of description, a +X direction inFIG.2may be described as a front direction, a −X direction as a back direction, a +Y direction as an up direction, a −Y direction as a down direction, a +Z direction as a right direction, and a −Z direction as a left direction.

FIG.2is a perspective view for describing a principle of a display by a display device10. The display device10forms a stereoscopic image, visually recognized by a user, in a space without a screen.FIG.2illustrates a state where the display device10displays a stereoscopic image I, more specifically, a button-shaped stereoscopic image I, on which characters “ON” are displayed.FIG.2illustrates a light guide plate11and a light source12among constituent elements included in the display device10.

The light guide plate11guides light incident from the light source12and emits the light from an outgoing surface11ato form the image in a space. The light guide plate11has a rectangular parallelepiped shape and is formed of a resin material having transparency and a relatively high refractive index. A material forming the light guide plate11may be, for example, polycarbonate resin, polymethyl methacrylate resin, glass, or the like. The light guide plate11includes an outgoing surface11a(light exit surface) that emits light, a back surface11bon the opposite side to the outgoing surface11a,and end faces11c,11d,11e,and11fthat are four end faces. The end face11cis an incident surface on which light projected from the light source12is incident on the light guide plate11. The end face11dis a surface on the opposite side to the end face11c.The end face11eis a surface on the opposite side to the end face11f.The light guide plate11spreads and guides the light from the light source12on a plane parallel to the outgoing surface11a.The light source12is, for example, a light-emitting diode (LED) light source.

On the back surface11bof the light guide plate11, a plurality of optical path changing units13, which include an optical path changing unit13a,an optical path changing unit13b,and an optical path changing unit13c,are formed. The optical path changing units13are formed substantially continuously in the Z-axis direction. In other words, the plurality of optical path changing units13are formed along respectively predetermined lines within a plane parallel to the outgoing surface11a.Light projected from the light source12and guided by the light guide plate11is incident on each of the positions in the Z-axis direction of the optical path changing units13. The optical path changing unit13substantially converges the light incident on each position of the optical path changing unit13to a definite point corresponding to each optical path changing unit13.FIG.2particularly illustrates the optical path changing unit13a,the optical path changing unit13b,and the optical path changing unit13cas some of the optical path changing units13. Specifically, a state is illustrated where light emitted from each of the optical path changing unit13a,the optical path changing unit13b,and the optical path changing unit13cconverges.

Specifically, the optical path changing unit13acorresponds to a definite point PA of the stereoscopic image I. Light from each position of the optical path changing unit13aconverges on the definite point PA. Thus, the wavefront of the light from the optical path changing unit13abecomes a wavefront of light that is as if emitted from the definite point PA. The optical path changing unit13bcorresponds to a definite point PB on the stereoscopic image I. Light from each position of the optical path changing unit13bconverges on the definite point PB. As described above, the light from each position of the arbitrary optical path changing unit13substantially converges on the definite point corresponding to each optical path changing unit13. Thereby, the arbitrary optical path changing unit13can provide a wavefront of light that is as if emitted from the corresponding definite point. The definite points corresponding to the respective optical path changing units13are different from each other, and the stereoscopic image I recognized by the user is formed on the space (more specifically, on the space on the outgoing surface11aside from the light guide plate11) by a collection of a plurality of definite points each corresponding to the optical path changing units13.

As illustrated inFIG.2, the optical path changing unit13a,the optical path changing unit13b,and the optical path changing unit13care formed along a line La, a line Lb, and a line Lc, respectively. Here, the line La, the line Lb, and the line

Lc are straight lines substantially parallel to the Z-axis direction. The arbitrary optical path changing unit13is formed substantially continuously along a straight line parallel to the Z-axis direction.

FIG.1is a view illustrating a specific configuration of the display device10according to the embodiment. InFIG.1, a perspective view of the display device10is indicated by reference numeral1001, and a side view thereof is indicated by reference numeral1002. As illustrated inFIG.1, the display device10includes a half mirror21and a mirror22in addition to the light guide plate11and the light source12described above.

The half mirror21is a half mirror that reflects a part of incident light and transmits the rest. The half mirror21is disposed on the outgoing surface11aside of the light guide plate11. The mirror22is a mirror that reflects incident light. The mirror22is disposed on the side of the light guide plate11opposite to the outgoing surface11a.

The light transmittance of the half mirror21is preferably 80% or less. In the display device10, blurring due to optical noise may occur in the image I formed. By setting the transmittance of the half mirror21to 80% or less, the optical noise is less likely to be visually recognized, and the visibility of the image I is improved. However, the light transmittance of each of the half mirror21and the mirror22may not necessarily be 80% or less.

FIG.3is a view illustrating an example of an optical path in the display device10. A part of the light emitted from the outgoing surface11aof the light guide plate11passes through the half mirror21and is emitted to the outside of the display device10as light L1. On the other hand, the light reflected by the half mirror21passes through the light guide plate11, is reflected by the mirror22, passes through the light guide plate11again, and reaches the half mirror21again. A part of the light having reached the half mirror21again is transmitted through the half mirror21and emitted to the outside of the display device10as light L2along an optical path different from the light L1.

The light reflected again by the half mirror21is further emitted toward the half mirror21via the light guide plate11, the mirror22, and the light guide plate11. In the example illustrated inFIG.3, the light emitted from the light guide plate11toward the half mirror21for the third time passes through the outside of the half mirror21and is emitted to the outside as light L3. However, depending on the emission position of the first light, the number of times the light emitted from the outgoing surface11ais reflected between the half mirror21and the mirror22may increase or decrease as compared with the example illustrated inFIG.3.

FIG.4is a view illustrating an example of the image I formed by the light guide plate11included in the display device10. With the light emitted from the outgoing surface11a,the light guide plate11forms the image I accompanied by a change that is made in a direction from the half mirror21toward the mirror22in a space different from the outgoing surface11a.The image I is, for example, a planar image having an angle larger than 0° with respect to the outgoing surface11a.In the example indicated by reference numerals4001and4002inFIG.4, the image I formed by the light guide plate11is a planar image parallel to a plane PI perpendicular to the outgoing surface11a.However, the image I may not be parallel to the plane PI perpendicular to the outgoing surface11a.The image I may be a stereoscopic image.

The light guide plate11forms the image I so that the image I can be visually recognized when the eyes of the user are arranged in a perpendicular direction (lateral direction) to a direction (longitudinal direction) in which the light incident from the light source12is guided in the light guide plate11. Note that the light guide plate11may form the image I so that the image I can be visually recognized when the eyes of the user are arranged not in the lateral direction but in the longitudinal direction or an oblique direction.

Further, in the example indicated by reference numerals4001and4002inFIG.4, a plurality of images I are aligned in a direction orthogonal to the direction in which the light from the light source12is guided in the light guide plate11. In the display device10, the shape of the image I can be controlled by the direction of the reflecting surface of the optical path changing unit13.

FIG.5is a view illustrating examples of the image I formed by the display device10. As illustrated inFIG.3, the light emitted from the outgoing surface11ais repeatedly reflected between the half mirror21and the mirror22. Therefore, when the display device10is visually recognized from the outgoing surface11aside of the light guide plate11, as indicated by reference numeral5001inFIG.5, a plurality of images I formed in the space are formed side by side in the depth direction.

The image I may have a shape of a switch protruding from the light guide plate11as indicated by reference numeral5002inFIG.5. The image I may have a shape of an arrow directed toward the light guide plate11as indicated by reference numeral5003inFIG.5. The image I may have a shape of a triangular prism separated from the light guide plate11as indicated by reference numeral5004inFIG.5.

The image I may be a rectangle on a plane not parallel to the light guide plate11as indicated by reference numerals5005to5007inFIG.5. In this case, an image B serving as a reference for visually recognizing the image I may be further displayed. The image B may be two-dimensional coordinate axes as indicated by reference numeral5005inFIG.5. The image B may be a plane on the light guide plate11as indicated by reference numeral5006inFIG.5. The image B may be three-dimensional coordinate axes as indicated by reference numeral5007inFIG.5.

FIG.6is a view illustrating a relationship of a distance between the half mirror21and the mirror22and an entire length of an image I in the depth direction of the display device10. As illustrated inFIG.6, the distance between the half mirror21and the mirror22is L1, and the entire length of the image I in the depth direction of the display device10is L2.

When L2is larger than twice L1, the multiply formed images I by the display device10have regions overlapping with each other. In this case, it is possible to make an expression as if the multiply formed images I were a single image continuous in the depth direction. On the other hand, when L2is equal to or less than twice L1, the multiply formed images I by the display device10do not have regions overlapping with each other. In this case, it is possible to make an expression as if many images I were gathered.

FIG.7is a perspective view illustrating examples of a game machine to which the display device10is applied. InFIG.7, the display device10is not illustrated. The display device10can be applied to an input device to be used in a device for amusement, such as a game machine. The input device includes the display device10and a sensor that detects the presence or absence of an object at a position of an image displayed by the display device10. When the user performs an input operation on the image displayed by the display device10with an indicator such as his or her finger, the sensor detects the indicator, and the input device receives the input.

As indicated by reference numeral7001inFIG.7, in an operation panel operated by the user on a game machine M1, the display device10may form the stereoscopic image I as at least one of a plurality of switches operated by the user. As indicated by reference numeral7002inFIG.7, the display device10may form the stereoscopic image I as a switch that is formed to be superimposed on the screen on which a performance image for the user is displayed in a game machine M2, the switch being operated by the user. In this case, the display device10may display the stereoscopic image I only when the display is necessary for performance. The display device10may be applied to a game machine not as an input device but as a display device that displays an image for performance. The display device10may be applied as an illumination provided on a frame or the like of a game machine installed in a casino or the like.

FIG.8is a view illustrating a state where the display device10is applied to a tail lamp of a vehicle C. The display device10can be applied to a tail lamp1A of the vehicle C, for example, as indicated by reference numeral8001inFIG.8. In this case, the display device10includes a light guide plate11A and the light source12as indicated by reference numeral8002inFIG.8. The light guide plate11A is different from the light guide plate11in that the light guide plate has a curved shape in accordance with the shape of the vehicle C. The optical path of the light incident from the light source12is changed by the optical path changing unit13formed in the light guide plate11A, whereby the stereoscopic image I is displayed. The display device10may be applied to a vehicle lamp other than the tail lamp or a vehicle display device.

Although the embodiments of the present invention have been described in detail above, the above description is merely an example of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. For example, the following modifications are possible. Hereinafter, the same reference numerals are used for the same constituent elements as those in the above embodiment, and the same description as in the above embodiment is omitted as appropriate. The following modifications can be combined as appropriate.

FIG.9is a view illustrating a display device110according to a first modification. For simplicity, the half mirror21and the mirror22are omitted inFIG.9. In the display device10illustrated inFIG.1, the plurality of images I have been aligned in the direction orthogonal to the direction in which the light from the light source12is guided in the light guide plate11. In contrast, in the display device110illustrated inFIG.9, a plurality of images I are formed to be arranged in the same direction as the direction in which the light from the light source12is guided through the light guide plate11. In the display device110, the width of the light guide plate11viewed from the light source12is narrower than that of the display device10. Therefore, in the display device110, the light incident on the light guide plate11from the light source12is appropriately collimated, and the shape of the image I is controlled in accordance with the direction of the reflecting surface of the optical path changing unit13.

FIG.10is a view illustrating a display device120according to a second modification. In the display device120, there is a difference in the image formed by the light guide plate11between the image formed on the half mirror21side of the outgoing surface11aand the image formed on the mirror22side of the outgoing surface11a.For example, as indicated by reference numeral10001inFIG.10, the light guide plate11forms an image IA on the front side of the paper surface with respect to the light guide plate11and forms an image IB on the back side of the paper surface with respect to the light guide plate11. Thus, as indicated by reference numeral10002inFIG.10, the display device120forms a plurality of images IA on the half mirror21side with respect to the light guide plate11and forms a plurality of images IB on the mirror22side with respect to the light guide plate11. Therefore, it is possible to display an image that changes between the front side and the back side of the light guide plate11in the depth direction. In the display device120, the images IA, IB may be planar images displayed on the front surface and the back surface of the light guide plate11, respectively, as indicated by reference numeral10003inFIG.10.

FIG.11is a view illustrating the light guide plate11included in a display device130(cf.FIG.12) according to a third modification. In the display device130, an image formed by the light guide plate11differs depending on a direction in which the image is formed. The light guide plate11in the display device130forms a different image IA, IB, or IC depending on the direction in which the image is formed as indicated by reference numerals11001,11002, and11003inFIG.11, for example.

FIG.12is a view illustrating a specific example of the image formed by the display device130. As indicated by reference numeral12001inFIG.12, the display device130forms a plurality of images IA in a direction in which the light guide plate11forms the image IA. On the other hand, as indicated by reference numeral12002inFIG.12, the display device130forms a plurality of images IB in a direction in which the light guide plate11forms the image IB. It is thus possible to multiply form different images depending on the direction in which the user views the display device130.

FIG.13is a view for describing a display device140according to a fourth modification. For simplicity, the half mirror21and the mirror22are omitted inFIG.13. In the display device140, the images I formed by the light guide plate11have a shape of convergence on the side where the mirror22is disposed with respect to the light guide plate11. For example, as indicated by reference numeral13001inFIG.13, the light guide plate11included in the display device140forms a plurality of images I. The plurality of images I have a design in which the images I converge on a predetermined vanishing point V.

Therefore, as indicated by reference numeral13002inFIG.13, images formed by the display device140also have a design in which the images converge on the predetermined vanishing point. Therefore, according to the display device140, it is possible to emphasize the stereoscopic effect of the images I.

In the light guide plate11included in the display device140, the plurality of images I need not necessarily have the design toward a predetermined vanishing point, but may have, for example, a design in which the images I converge on a predetermined vanishing line.

FIG.14is a view for describing a display device150according to a fifth modification. For simplicity, the half mirror21and the mirror22are omitted inFIG.14. As indicated by reference numeral14001inFIG.14, the light guide plate11included in the display device150forms an image ID parallel to the outgoing surface11ain addition to the plurality of images I.

In the multiply formed images by the display device150, the plurality of images I and images ID parallel to the outgoing surface11aare formed multiply as indicated by reference numeral14002inFIG.14. At this time, a plane on which the image ID is formed serves as a reference plane in the case of visually recognizing the images I. Therefore, according to the display device150, it is possible to emphasize the stereoscopic effect of the images I.

FIG.15is a view illustrating a display device160according to a sixth modification. As indicated by reference numerals15001and15002inFIG.15, the display device160further includes a light emitting member23in addition to the configuration of the display device10. The light emitting member23has a predetermined shape and emits light. The light emitting member23is provided in a region between the half mirror21and the mirror22. The light emitting member23may include, for example, a light source and a light guide plate for a light emitting member. The light emitting member23may be a plurality of LEDs arranged in a predetermined shape.

In images multiply formed by the display device160, the images I and images IE of the light emitting member23are formed multiply as indicated by reference numeral15003inFIG.15. At this time, the position of the image IE of the light emitting member23serves as a reference position in the case of visually recognizing the images I. Therefore, according to the display device160, it is possible to emphasize the stereoscopic effect of the images I.

FIG.16is a view illustrating a display device170according to a seventh modification. In the display device170, one of the half mirror21and the mirror22is formed on the front surface of the light guide plate11. In an example indicated by reference numeral16001inFIG.16, the half mirror21is deposited on the front surface of the light guide plate11. In this case, the display device170multiply forms the images I only on the mirror22side. In an example indicated by reference numeral16002inFIG.16, the mirror22is deposited on the front surface of the light guide plate11. In this case, the display device170multiply forms the images I only on the half mirror21side.

One of the half mirror21and the mirror22may be formed on the front surface of the light guide plate11by a method other than vapor deposition. In the display device170, the number of components and the space of the display device170can be reduced by forming the half mirror21or the mirror22on the front surface of the light guide plate11.

FIG.17is a view illustrating a display device180according to an eighth modification. As indicated by reference numeral17001inFIG.17, in the display device180, the half mirror21and the mirror22are longer than the light guide plate11in a direction parallel to the light guide plate11. Thus, in the display device180, the light emitted from the light guide plate11is repeatedly reflected in a wider range than the light guide plate11in a direction parallel to the front surface of the light guide plate11to form the image I. Therefore, according to the display device180, as indicated by reference numeral17001inFIG.17, even when a viewpoint E of the user is farther from the center of the light guide plate11than from the end of the light guide plate11in the direction parallel to the light guide plate11, it is possible to give a sense of depth to the multiply formed images I.

However, in the display device180, as indicated by reference numeral17002inFIG.17, the half mirror21and the mirror22only needs to be longer than the length of a region R where the optical path changing unit13is provided in the direction parallel to the light guide plate11. Such a display device180can also give a sense of depth to the multiply formed images I when the viewpoint E of the user is farther from the center of the light guide plate11than from the end of the light guide plate11in the direction parallel to the light guide plate11.

FIG.18is a view illustrating a display device190according to a ninth modification. For simplicity, the light source12is omitted inFIG.18. As illustrated inFIG.18, in the display device190, the light guide plate11, the half mirror21, and the mirror22are curved so as to be convex toward the side where the images I are observed. According to such a display device190, it is possible to form a plurality of curved images I.

FIG.19is a view illustrating a display device200according to a tenth modification. For simplicity, the mirror22is omitted inFIG.19. As illustrated inFIG.19, in addition to the configuration of the display device10, the display device200further includes a cover24that transmits at least a part of the incident light on the side of the half mirror21opposite to the light guide plate11. In the display device200, the light transmittance of the half mirror21is lower than the light transmittance of the cover24.

As described above, in the display device10, blurring due to optical noise may occur in the image I formed. In the display device200, with the provision of the cover24, the optical noise is less likely to be visually recognized, thereby improving the visibility of the image I.

FIG.20is a view illustrating a display device210according to an eleventh modification. The display device210is applicable to, for example, a rear combination lamp of a vehicle. As indicated by reference numerals20001and20002inFIG.20, the display device210further includes an inner cover40in addition to the configuration of the display device10. By applying the display device210to the rear combination lamp, it is possible to achieve a rear combination lamp capable of forming a deep image while saving space.

FIG.21is a view illustrating a display device220according to a twelfth modification. For simplicity, the half mirror21and the mirror22are omitted inFIG.21. As indicated by reference numerals21001and21002inFIG.21, the display device220includes a blinker41and a brake lamp42in addition to the configuration of the display device10. In other words, the display device220has a configuration in which the blinker41and the brake lamp42are superimposed on the light guide plate11.

In the display device220, in addition to the images I, light during the operation of the blinker41and/or the brake lamp42is formed multiply. Therefore, according to the display device220, it is possible to achieve a vehicle lamp with high taste also for each of the blinker41and the brake lamp42.

In the display device220, the blinker41and the brake lamp42are disposed, for example, between the light guide plate11and the mirror22. In the display device220, the blinker41and the brake lamp42may be disposed between the light guide plate11and the half mirror21. However, in the display device220, the blinker41and the brake lamp42may not necessarily be disposed on the same side with respect to the light guide plate11. In addition, the display device220need not necessarily include both the blinker41and the brake lamp42but may include only one.

A display device10A as a thirteenth modification will be described with reference toFIGS.22to27.

FIG.22is a perspective view of the display device10A.FIG.23is a cross-sectional view illustrating the configuration of the display device10A.FIG.24is a plan view illustrating the configuration of the display device10A.FIG.25is a perspective view illustrating a configuration of an optical path changing unit16included in the display device10A.

As illustrated inFIGS.22and23, the display device10A includes the light source12and a light guide plate15(first light guide plate).

The light guide plate15is a member that guides light (incident light) incident from the light source12. The light guide plate15is formed of a transparent resin material having a relatively high refractive index. As a material for forming the light guide plate15, for example, polycarbonate resin, polymethyl methacrylate resin, or the like can be used. In the modification, the light guide plate15is molded with polymethyl methacrylate resin. As illustrated inFIG.23, the light guide plate15includes an outgoing surface15a(light exit surface), a back surface15b,and an incident surface15c.

The outgoing surface15ais a surface that emits light guided inside the light guide plate15and changed in its optical path by an optical path changing unit16to be described later. The outgoing surface15aconstitutes the front surface of the light guide plate15. The back surface15bis a surface parallel to the outgoing surface15aand is a surface on which the optical path changing unit16to be described later is disposed. The incident surface15cis a surface on which the light emitted from the light source12enters the light guide plate15.

The light emitted from the light source12and incident on the light guide plate15from the incident surface15cis totally reflected by the outgoing surface15aor the back surface15band guided in the light guide plate15.

As illustrated inFIG.23, the optical path changing unit16is a member that is formed on the back surface15binside the light guide plate15, changes the optical path of the light guided in the light guide plate15, and emits the light from the outgoing surface15a.A plurality of optical path changing units16are provided on the back surface15bof the light guide plate15.

As illustrated inFIG.24, the optical path changing units16are provided along a direction parallel to the incident surface15c.As illustrated inFIG.25, the optical path changing unit16has a triangular pyramid shape and includes a reflecting surface16athat reflects (totally reflects) incident light. The optical path changing unit16may be, for example, a recess formed in the back surface15bof the light guide plate15. The optical path changing unit16is not limited to the triangular pyramid shape. As illustrated inFIG.24, a plurality of optical path changing unit groups17a,17b,17c, . . . each made up of a plurality of optical path changing units16are formed on the back surface15bof the light guide plate15.

FIG.26is a perspective view illustrating the arrangement of the optical path changing units16. As illustrated inFIG.26, in each of the optical path changing unit groups17a,17b,17c, . . . , the reflecting surfaces16aof the plurality of optical path changing units16are arranged on the back surface15bof the light guide plate15such that the angles with respect to the incident direction of light are different from each other. Thereby, each of the optical path changing unit groups17a,17b,17c, . . . changes the optical path of the incident light and emits the incident light from the outgoing surface15ain various directions.

Next, a method for formation of the stereoscopic image I by the display device10A will be described with reference toFIG.27. Here, a case will be described in which the stereoscopic image I as a plane image is formed on a stereoscopic image formed plane P, which is a plane perpendicular to the outgoing surface15aof the light guide plate15, by the light changed in its optical path by the optical path changing unit16.

FIG.27is a perspective view illustrating the method for formation of the stereoscopic image I by the display device10A. Here, the formation of a ring mark with a diagonal line as the stereoscopic image I on the stereoscopic image formed plane P will be described.

In the display device10A, as illustrated inFIG.27, for example, the light changed in its optical path by each optical path changing unit16of the optical path changing unit group17aintersects with the stereoscopic image formed plane P on each of a line La1and a line La2. Thereby, a line image LI which is a part of the stereoscopic image I is formed on the stereoscopic image formed plane P. The line image LI is a line image parallel to the YZ plane. In this manner, the line image LI of the line La1and the line La2is formed by the light from each of many optical path changing units16belonging to the optical path changing unit group17a.Note that the light for forming the images of the lines La1, La2only needs to be provided by at least two optical path changing units16in the optical path changing unit group17a.

Likewise, the light changed in its optical path by each optical path changing unit16of the optical path changing unit group17bintersects with the stereoscopic image formed plane P on each of lines Lb1, Lb2, and Lb3. Thereby, a line image LI which is a part of the stereoscopic image I is formed on the stereoscopic image formed plane P.

The light changed in its optical path by each optical path changing unit16of the optical path changing unit group17cintersects with the stereoscopic image formed plane P on each of lines Lc1and Lc2. Thereby, a line image LI which is a part of the stereoscopic image I is formed on the stereoscopic image formed plane P.

The positions in the X-axis direction of the line images LI formed by the optical path changing unit groups17a,17b,17c, . . . are different from each other. In the display device10A, by reducing the distance between the optical path changing unit groups17a,17b,17c, . . . , the distance in the X-axis direction of the line image LI formed by each of the optical path changing unit groups17a,17b,17c, . . . can be reduced. As a result, the display device10A accumulates the plurality of line images LI formed by the light changed in its optical path by each of the optical path changing units16of the optical path changing unit groups17a,17b,17c, . . . , thereby substantially forming the stereoscopic image I, which is a plane image, on the stereoscopic image formed plane P.

Note that the stereoscopic image formed plane P may be a plane perpendicular to the X-axis, a plane perpendicular to the Y-axis, or a plane perpendicular to the Z-axis. Further, the stereoscopic image formed plane P may be a plane that is not perpendicular to the X-axis, the Y-axis, or the Z-axis. Moreover, the stereoscopic image formed plane P may be a curved plane instead of a flat plane. That is, the display device10A can cause the optical path changing unit16to form the stereoscopic image I on an arbitrary plane (flat plane and curved plane) on the space. By combining a plurality of plane images, a three-dimensional image can be formed.

The display device10may separately form images for a plurality of viewpoints. For example, the display device10may include a right-eye display pattern for forming a right-eye image and a left-eye display pattern for forming a left-eye image. In this case, the display device10can form an image having a stereoscopic effect. The display device10may separately form images for three or more viewpoints.

SUMMARY

A display device according to one aspect of the present invention is provided with: a light guide plate configured to guide incident light, reflect the light by an optical path changing unit formed at a predetermined position, and emit the light from a light exit surface; a half mirror disposed on the light-exit-surface side of the light guide plate; and a mirror disposed on a side of the light guide plate opposite to the light exit surface. The light guide plate forms an image accompanied by a change that is made in a direction from the half mirror toward the mirror in a space different from the light exit surface by light emitted from the light exit surface.

With the above configuration, the image formed by the light guide plate is repeatedly reflected between the half mirror and the mirror. Therefore, when viewed from the light-exit-surface side of the light guide plate, it is possible to display multiple images in which a plurality of images formed in the space are arranged in the depth direction. Here, the image formed in the space is an image accompanied by a change that is made in a direction from the half mirror toward the mirror. By such an image becoming multiple images displayed further in the depth direction, it is possible to provide a display with high taste and excellent design.

In the display device according to one aspect of the present invention, when a distance between the half mirror and the mirror is L1, and an entire length of an image formed by the light guide plate in a direction from the half mirror toward the mirror is L2, L2may be larger than twice L1.

With the above configuration, the multiply formed images have regions overlapping with each other. It is thus possible to make an expression as if the multiply formed images were a single image continuous in the depth direction.

In the display device according to one aspect of the present invention, when a distance between the half mirror and the mirror is L1, and an entire length of an image formed by the light guide plate in a direction in which the mirror is disposed is L2, L2may be twice L1or less.

With the above configuration, the multiply formed images do not have regions overlapping with each other. Therefore, by multiply forming images, it is possible to make an expression as if many images were gathered.

In the display device according to one aspect of the present invention, there may be a difference in an image formed by the light guide plate between an image formed on the side of the half mirror with respect to the light exit surface and an image formed on the side of the mirror with respect to the light exit surface.

With the above configuration, it is possible to display an image that changes between the front side and the back side of the light guide plate in the depth direction.

In the display device according to one aspect of the present invention, an image formed by the light guide plate may differ depending on a direction in which the image is formed.

With the above configuration, it is possible to display an image that changes depending on the direction in which the display device is viewed.

In the display device according to one aspect of the present invention, images formed by the light guide plate may have a shape of convergence on a side where the mirror is disposed with respect to the light guide plate.

With the above configuration, the multiply formed images also have a shape of convergence on the side where the mirror is disposed with respect to the light guide plate, so that it is possible to emphasize the stereoscopic effect of the image.

In the display device according to one aspect of the present invention, the mirror and the half mirror may be longer than a region where the optical path changing unit is provided in a direction parallel to the light guide plate.

With the above configuration, even when the viewpoint of the user is farther from the center of the light guide plate than from the end of the light guide plate, it is possible to give a sense of depth to the multiply formed images.

In the display device according to one aspect of the present invention, the mirror and the half mirror may be longer than the light guide plate in the direction parallel to the light guide plate.

With the above configuration, even when the viewpoint of the user is farther from the center of the light guide plate than from the end of the light guide plate, it is possible to give a sense of depth to the multiply formed images.

In the display device according to one aspect of the present invention, one of the half mirror and the mirror may be formed on the front surface of the light guide plate.

With the above configuration, it is possible to reduce the number of components and the space of the display device.

In the display device according to one aspect of the present invention, the light guide plate, the half mirror, and the mirror may be curved so as to be convex toward a side where the image is observed.

With the above configuration, it is possible to multiply form curved images.

In the display device according to one aspect of the present invention, the light transmittance of the half mirror may be 80% or less.

With the above configuration, optical noise is less likely to be visually recognized, and the visibility of the image is improved.

The display device according to one aspect of the present invention may further include a cover disposed on the side of the half mirror opposite to the light guide plate, and the light transmittance of the half mirror may be lower than a light transmittance of the cover.

With the above configuration, optical noise is less likely to be visually recognized, and the visibility of the image is improved.

The present invention is not limited to each of the embodiments described above but can be subjected to a variety of changes in the scope described in the claims. An embodiment obtained by appropriately combining technical means disclosed in each of different embodiments is also included in a technical scope of the present invention.

DESCRIPTION OF SYMBOLS

10,110,120,130,140,150,160,170,180,190,200,210,220,10A display device

11light guide plate