Patent Description:
Aerial imaging by retro-reflection (AIRR) is known (for example, <CIT>, <CIT>, and <CIT>). For example, an aerial image display device of <CIT> discloses a structure in which a display and a retroreflective member are disposed parallel to a beam splitter, and a deflection optical element is disposed on the display in order to reduce a thickness of the device.

Non-contact buttons have been rapidly expanded as input functions required for elevators and the like. <FIG> is an example of an input device <NUM> provided in an elevator, and buttons <NUM> configured to input floor numbers and buttons <NUM> configured to input opening and closing of a door are mounted. The buttons <NUM> and <NUM> incorporate miniaturized non-contact sensors, respectively, so that actions of a user such as approach and placement of a hand with respect to the buttons <NUM> and <NUM> is detected. In addition, in a case where an aerial image <NUM> is displayed above the buttons <NUM> and <NUM> using retro-reflection, the non-contact sensor detects the actions of the user such as the approach of the hand and the placement of the hand with respect to the aerial image <NUM>.

In a case where an input operation of the user is detected by the non-contact sensor, the user can perform the input in a non-contact manner, but there is a problem that it is difficult to know whether or not the input has been confirmed when the user places the hand on the aerial image <NUM>. In addition, in a case where the aerial image of the button is displayed, it is required to achieve a reduction in thickness of the input device.

<CIT> discloses an optical device which includes a light guiding plate which guides lights within the surface parallel to an emission surface, and light converging sections onto which the lights guided by the light guiding plate are incident. A display apparatus displays a stereoscopic image similar to the image of a virtual switch. A touch panel is provided on the main surface side of the display apparatus. The display apparatus forms the stereoscopic image of a virtual switch overlapping a planar image displayed by the display section of the touch panel.

<CIT> discloses an aerial image display system with an image display device provided with image display equipment for displaying an image on a screen on the basis of an acquired image signal.

<CIT> discloses an input device which comprises a light-guide plate that guides light from a light source, emits same from an emission surface, and forms a three-dimensional image that serves as a target for user input operations. A position detection sensor detects a finger used by the user for input operations. An input detection unit detects inputs by the user and a notification unit that notifies that a user input has been detected. The position detection sensor is arranged in a space on the opposite side to the emission surface.

<CIT> discloses an input device in which a light-guide plate guides light from a light source and causes an image to be formed in a space. A sensor detects an object in the space that includes the position at which the image is formed.

An object of the present invention is to provide an input device capable of notifying input confirmation and achieving a reduction in thickness.

The invention relates to an input device according to the appended claims. Embodiments are disclosed in the dependent claims.

According to the present invention a display unit as set forth in claim <NUM> is provided.

In an embodiment, the detection unit includes an open/close switch to detect the pressing of the display unit. In an embodiment, when the user operation is detected, the display unit turns off the light source and causes the aerial image not to be displayed. In an embodiment, the light guide plate includes first and second light guide plates which are stacked, and the light source includes first and second light sources respectively corresponding to the first and second light guide plates, and the display unit turns on one of the first and second light sources and turns off another of the first and second light sources based on the detection result of the detection unit. In an embodiment, the second light guide plate is farther from the beam splitter than the first light guide plate, and the display unit turns off the first light source and turns on the second light source to display a second aerial image, and, when a user operation related to the second aerial image using the second light guide plate is detected, turns off the second light source and turns on the first light source to displays a first aerial image using the first light guide plate. In an embodiment, the first aerial image using the first light guide plate is smaller than the second aerial image using the second light guide plate. In an embodiment, a color of light emitted from the first light source is different from a color of light emitted from the second light source. In an embodiment, the display unit further includes a lens whose focal length is electrically changeable, and the display unit changes the focal length of the lens based on the detection result of the detection unit. In an embodiment, the display unit changes a size or a display position of the aerial image when the user operation is detected.

According to the present invention, the display unit switches on and off of the light source based on the detection result of the detection unit, and thus, the user can know the input confirmation through the display of the aerial image. In addition, it is possible to achieve the reduction in the thickness of the input device by detecting pressing of the display unit.

Next, embodiments of the present invention will be described. An input device according to aspects of the present invention is an input device in which a function of displaying an aerial image using retro-reflection and a function of detecting a user operation are integrated. It should be noted that the drawings referred to in the following description of the embodiments include exaggerated display in order to facilitate understanding of the invention, and do not directly represent the shape and scale of an actual product.

Next, an embodiment of the present invention will be described in detail. <FIG> are schematic cross-sectional views illustrating a configuration of an input device according to a first embodiment of the present invention. An input device <NUM> of the present embodiment includes a display unit <NUM> having a function of displaying an aerial image, and a detection unit <NUM> having a function of detecting a user operation related to the aerial image displayed by the display unit <NUM>.

The display unit <NUM> includes, for example, a light guide plate <NUM>, a light source <NUM>, a half mirror <NUM>, and a retroreflective plate <NUM> in a rectangular housing <NUM> in which a space is formed.

The light guide plate <NUM> is a transparent plate-like or film-like optical member including a flat upper surface, a flat bottom surface, and side surfaces connecting the upper surface and the bottom surface. A known plate can be used as the light guide plate <NUM>, and may be made of, for example, glass, acrylic plastic, a polycarbonate resin, a cycloolefin-based resin, or the like. A light diffusion surface <NUM> is formed on the bottom or bottom surface of the light guide plate <NUM>. The light diffusion surface <NUM> is formed, for example, by performing laser processing or printing processing on the bottom surface of the light guide plate <NUM>. The light diffusion surface <NUM> forms a design that is an original image to generate the aerial image. The design is, for example, a number representing a floor number of an input button <NUM> as illustrated in <FIG>.

The light source <NUM> is disposed on a side portion of the light guide plate <NUM>. The light source <NUM> is not particularly limited, but, for example, a light emitting diode, a laser diode, or the like may be used. The light source <NUM> emits light having a constant emission angle (or radiation angle) toward the side portion of the light guide plate <NUM>, and uniformly irradiates the inside of the light guide plate <NUM>. The light diffusion surface <NUM> of the light guide plate <NUM> diffuses or scatters the incident light upward.

The half mirror <NUM> is disposed on the upper surface side of the light guide plate <NUM>. The half mirror <NUM> is a transparent optical member which separates incident light into reflected light and transmitted light. The half mirror <NUM> is configured by, for example, forming a dielectric multilayer film, an anti-reflection film, or the like on a front surface or a back surface of a substrate of such as flat glass or plastic. Here, the half mirror <NUM> in which the amount of the reflected light and the amount of the transmitted light are equal is exemplified, but a beam splitter in which a ratio between the amount of reflected light and the amount of transmitted light differs depending on the luminance of the light source <NUM> or the luminance of the aerial image may be used.

The retroreflective plate <NUM> is attached so as to be in contact with the bottom surface of the light guide plate <NUM>. The retroreflective plate <NUM> is an optical member that reflects light in the same direction as the incident light and includes, for example, a prismatic retroreflective element such as a triangular pyramid retroreflective element and full cube corner retroreflective element, or beaded retroreflective element although its configuration is not particularly limited.

The light incident from the side portion of the light guide plate <NUM> is diffused or scattered upward by the light diffusion surface <NUM>, a part of the diffused or scattered light is reflected by the half mirror <NUM>, and the reflected light thereof is incident on the retroreflective plate <NUM>. The light incident on the retroreflective plate <NUM> is reflected in the same direction as the incident light, and a part thereof is transmitted through the half mirror <NUM> and forms an image again. As a result, an aerial image <NUM> floating from the display unit <NUM> is observed from the viewpoint of a user.

The detection unit <NUM> is disposed on a bottom surface side of the display unit <NUM>. When the display unit <NUM> is operated by the user, the detection unit <NUM> detects the operation. In use, the user visually recognizes the aerial image <NUM> displayed by the display unit <NUM> and presses the display unit <NUM> to perform input. The display unit <NUM> functions as an input button, and changes its position when being pressed by the user. The detection unit <NUM> detects a position change of the display unit <NUM> as the user operation.

As a specific example, the detection unit <NUM> includes a switch whose contact is physically or mechanically opened and closed, and the contact of the switch is opened and closed by protrusions <NUM> in contact with a bottom surface of a housing <NUM> of the display unit <NUM>. The protrusion <NUM> is elastically biased to the bottom surface of the housing by an elastic member such as a spring, and the switch is opened or closed, for example, when the display unit <NUM> is pressed against an elastic force thereof. A result of opening and closing of the switch is provided to a controller (not illustrated) or the like.

<FIG> illustrates a state in which the aerial image <NUM> is displayed by the display unit <NUM> and the display unit <NUM> is not pressed by a user U. At this time, the protrusion <NUM> protrudes from the detection unit <NUM> and elastically biases the bottom surface of the housing <NUM>.

<FIG> illustrates a state in which the user visually recognizes the aerial image <NUM> and presses the display unit <NUM>. When the user U presses the display unit <NUM>, the display unit <NUM> moves to the right, and the protrusion <NUM> is recessed inward by the movement, whereby the switch is opened and closed.

In this manner, it is possible to reduce the thickness of the input device <NUM> by integrating the display unit <NUM> and the detection unit <NUM> while securing the state in which the display unit <NUM> can be pressed by visually recognizing the aerial image <NUM> in the input device <NUM> of the present embodiment. In addition, the user U can know that the input has been confirmed by physically pressing the display unit <NUM>.

Note that the display unit <NUM> that generates the aerial image is not limited to the configuration illustrated in <FIG>, and for example, the half mirror <NUM> may be changed to a polarization beam splitter, and a λ/<NUM> plate may be inserted between the light guide plate <NUM> and the retroreflective plate <NUM>. As a result, the aerial image <NUM> can be displayed using polarized light.

<FIG> are views illustrating configurations of an input device 100A according to the second embodiment, and the same configurations as those in <FIG> are denoted by the same reference signs. In the present embodiment, a detection unit <NUM> provides a detection result of a user operation to a display unit 200A, and the display unit 200A switches on and off of a light source <NUM> according to the detection result.

The detection unit <NUM> includes a switch <NUM> that is opened and closed depending on positions of protrusions <NUM>, which is similar to the first embodiment. For example, the switch <NUM> is configured to be closed when the display unit 200A is not pressed by a user U as illustrated in <FIG>, and to be opened when the display unit 200A is pressed by the user U as illustrated in <FIG>. The switch <NUM> provides a voltage signal Vd to the display unit 200A when the switch <NUM> is closed, and provides a signal at the GND level to the display unit 200A when the switch <NUM> is opened. In one example, the protrusions <NUM> may be made of a conductive material, and signals indicating opening and closing of the switch <NUM> may be provided to the display unit 200A using one of the protrusions <NUM> as a part of a current path.

When the display unit 200A is not pressed by the user U as illustrated in <FIG>, the display unit 200A turns on the light source <NUM> based on the voltage signal Vd to display an aerial image <NUM>. On the other hand, when the display unit 200A is pressed by the user U as illustrated in <FIG>, the display unit 200A turns off the light source <NUM> based on the signal at the GND level not to display the aerial image <NUM>. Since the aerial image <NUM> is not displayed in synchronization with the pressing of the display unit 200A, the user can visually recognize that the input has been confirmed.

In this manner, it is possible to notify the user of the input confirmation by switching on and off of the light source <NUM> depending on the detection result of the user operation to perform display and non-display of the aerial image <NUM> according to the present embodiment. In addition, it is possible to achieve a reduction in thickness of the input device since the pressing of the display unit 200A is detected (the amount of pressing may be small).

Next, a third embodiment of the present invention will be described. <FIG> are views illustrating configurations of an input device 100B according to the third embodiment, and the same configurations as those in <FIG> are denoted by the same reference signs.

A display unit 200B of the present embodiment includes two stacked light guide plates <NUM> and 220A. The two light guide plates <NUM> and 220A may have the same configuration, or designs of light diffusion surfaces <NUM> and 222A may be different from each other. In addition, two light sources <NUM> and 230A are provided so as to correspond to the two light guide plates <NUM> and 220A. The two light sources <NUM> and 230A may have the same configuration or may emit beams of light of different wavelengths (colors), respectively.

The light guide plate 220A is disposed on a bottom surface side of the light guide plate <NUM>, and a retroreflective plate <NUM> is disposed on a bottom surface side of the light guide plate 220A. The display unit 200B turns on any one of the light sources <NUM> and 230A, thereby displaying aerial images <NUM> and 260A by any one of the light guide plates <NUM> and 220A. As a preferable aspect, the display unit 200B turns off the light source <NUM> and turns on the light source 230A to irradiate the light guide plate 220A as illustrated in <FIG>. Light diffused or scattered by the light diffusion surface 222A of the light guide plate 220A is transmitted through the light guide plate <NUM>, is partially reflected by a half mirror <NUM>, and the reflected light thereof enters the retroreflective plate <NUM> via the light guide plates <NUM> and 220A. The retroreflective plate <NUM> reflects light in the same direction as the incident light, the reflected light thereof is transmitted through the light guide plates 220A and <NUM>, and a part of the transmitted light is transmitted through the half mirror <NUM>. In this manner, the aerial image 260A using the light guide plate 220A is displayed. The aerial image 260A is generated at a line-symmetric position with respect to the half mirror <NUM>, and thus, the aerial image 260A is displayed so as to float relatively high from the display unit 200B.

When a user U visually recognizes the aerial image 260A and presses the display unit 200B as a user operation, such pressing is detected by a detection unit <NUM>, and a detection result is provided to the display unit 200B. A state at this time is illustrated in <FIG>. When the pressing of the user is detected by the detection unit <NUM>, the display unit 200B turns on the light source <NUM> and turns off the light source 230A to irradiate the light guide plate <NUM>. Light diffused or scattered by the light diffusion surface <NUM> of the light guide plate <NUM> is partially reflected by the half mirror <NUM>, and the reflected light thereof enters the retroreflective plate <NUM> via the light guide plates <NUM> and 220A. The retroreflective plate <NUM> reflects light in the same direction as the incident light, the reflected light thereof is transmitted through the light guide plates 220A and <NUM>, and a part of the transmitted light is transmitted through the half mirror <NUM>. In this manner, the aerial image <NUM> using the light guide plate <NUM> is displayed. The aerial image <NUM> has a lower floating height than the aerial image 260A.

In this manner, the user can know input confirmation by visually recognizing that a display position of the aerial image changes in synchronization with the user operation according to the present embodiment. Note that a size or a shape of the light diffusion surface <NUM> of the light guide plate <NUM> may be different from that of the light diffusion surface 222A of the light guide plate 220A. In this case, the user can know the input confirmation based on a change in size or shape of the aerial image <NUM>. Furthermore, colors of the light source <NUM> and the light source 230A may be changed. In this case, the user can know the input confirmation based on a change in color of the aerial image <NUM>.

Next, a fourth embodiment of the present invention will be described. <FIG> are views illustrating configurations of an input device 100C according to the fourth embodiment, and the same configurations as those in <FIG> are denoted by the same reference signs. A display unit 200C of the present embodiment includes an electron lens <NUM> in front of a half mirror <NUM> in addition to the configurations of the display unit 200A of the second embodiment. The electron lens <NUM> is a concave lens or a convex lens whose focal length can be electrically changed. For example, the electron lens <NUM> is configured using a liquid crystal lens. In addition, a protective glass or the like may be disposed on the surface of the electron lens <NUM> in order to protect the electron lens <NUM> from a user operation.

A detection unit <NUM> detects pressing of the display unit 200C and provides a detection result to the display unit 200C, which is similar to the above-described embodiments. The display unit 200C changes the focal length of the electron lens <NUM> depending on the detection result, thereby changing a display position (hover height) and a dimension (size) of an aerial image.

<FIG> illustrates a state in which pressing by a user U is not performed. At this time, the display unit 200C adjusts the focal length of the electron lens <NUM>, and causes an aerial image <NUM> to be displayed so as to float relatively far from the display unit 200C.

<FIG> illustrates a state in which the pressing by the user U is performed. The display unit 200C adjusts the focal length of the electron lens <NUM> such that an aerial image 260C is displayed at a position relatively close to the display unit 200C with a small size in response to the detection of the pressing of the display unit 200C by the detection unit <NUM>.

In this manner, the user can know input confirmation by visually recognizing that changes in the hover height and the size of the aerial image in synchronization with the user operation according to the present embodiment.

Although the switch <NUM> whose contact is opened and closed by the movement of the protrusions <NUM> is exemplified as the detection unit <NUM> in the above-described embodiments, the detection unit <NUM> is not necessarily limited to such a switch and may be a switch having another configuration. For example, as illustrated in <FIG>, a switch <NUM> as a detection unit <NUM> may be built in a housing <NUM> of a display unit 200D, and protrusions <NUM> may protrude from a bottom surface of the housing <NUM>. In this case, the protrusions <NUM> protrude to open the switch <NUM> when the display unit 200D is not pressed as illustrated in <FIG>, and the protrusions <NUM> come into contact with a stationary member <NUM> and are recessed to close the switch <NUM> when the display unit 200D is pressed as illustrated in <FIG>. The display unit 200D switches on and off of a light source <NUM> depending on the opening and closing of the switch <NUM>. With such a configuration, an input device 100D can be further reduced in thickness.

A spatial input device of the present example can be applied to any user input, and can be applied to, for example, a computer device, an in-vehicle electronic device, an ATM of a bank or the like, a ticket purchasing machine of a station or the like, an input button of an elevator, and the like.

Claim 1:
An input device (<NUM>) comprising:
a display unit (<NUM>) including a light guide plate (<NUM>) disposed between a beam splitter (<NUM>) and a retroreflective member (<NUM>) and a light source (<NUM>) irradiating the light guide plate (<NUM>), and configured to display an aerial image (<NUM>) of a light diffusion surface (<NUM>) formed on the light guide plate (<NUM>) in response to incident light; characterized by
a detection unit (<NUM>) disposed on a bottom surface side of the display unit (<NUM>) and configured to detect a user operation related to the aerial image (<NUM>), wherein the display unit (<NUM>) changes its position when being pressed by the user to perform input and the detection unit (<NUM>) detects a position change of the display unit (<NUM>) as the user operation, wherein
the display unit (<NUM>) switches on and off of the light source (<NUM>) based on a detection result of the detection unit (<NUM>).