non-contact switch

Abstract

To provide a non-contact switch that can clarify a position at which operation input is received and improve the sensitivity of detecting the operation input.SOLUTION: A non-contact switch has: a stereoscopic display unit 11 that can display a stereoscopic image 21 indicating a position to receive operation input; a light guide plate 13 that is arranged on the back side of the stereoscopic display unit 11 and directs illumination light toward the stereoscopic display unit 11; a light shielding unit 12 that is arranged between the stereoscopic display unit 11 and the light guide plate 13 and in which a pattern 22 indicating the position is formed; a detection unit 14 that is arranged on the back side of the light guide plate 13 and has a light emitting device 141 emitting sensor light and a light receiving device 142 outputting a detection signal upon detection of the sensor light; a first reflection member 181 that has a reflection surface formed in a convex surface shape with respect to the light emitting device 141 of the detection unit 14; and a second reflection member 182 that has a reflection surface formed in a concave surface shape or in a planar shape with respect to the light receiving device 142 of the detection unit 14.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a non-contact switch that allows for non-contact operation input. [Background technology]

[0002] From the viewpoint of hygiene or preventing the spread of infectious diseases, research has been conducted into contactless switches that allow a user to perform an operation input without touching any component (see, for example, Patent Document 1).

[0003] For example, the input device disclosed in Patent Document 1 includes a light source, a light guide plate, a sensor, and a second image. The light guide plate guides light from the light source to form a first image in space. The sensor detects an object in the space including the position where the first image is formed or in a space a predetermined distance away from the position where the first image is formed. The second image is displayed on a surface different from the surface on which the first image is displayed. A controller changes the displayed first image in response to a user's input operation on the first image. Furthermore, a light guide plate or a display device for displaying the second image is provided, and the controller changes the displayed second image in response to the input operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-64632 Summary of the Invention [Problem to be solved by the invention]

[0005] The input device disclosed in Patent Document 1 is configured to make it easier to obtain a three-dimensional effect in an image. However, in order to improve usability, it is preferable that the position where an operation input is accepted be more clear.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a non-contact switch that clarifies the position at which an operational input is accepted and that can improve the detection sensitivity of the operational input. [Means for solving the problem]

[0007] One aspect of the present invention provides a non-contact switch, which includes: a first light source; a three-dimensional display unit arranged on the rear side, which displays a pattern indicating a position where an operation input is to be accepted from the front side and which is capable of displaying a three-dimensional image indicating the position by light emitted from the first light source; a second light source emitting illumination light whose emission color can be changed; a light guide plate arranged on the rear side of the three-dimensional display unit and which directs the illumination light emitted from the second light source toward the three-dimensional display unit; a light-shielding portion arranged between the three-dimensional display unit and the light guide plate, which has a light-shielding region that blocks sensor light and illumination light and a light-transmitting region that transmits the sensor light and illumination light, and in which the light-shielding region forms a pattern indicating the position where an operation input is to be accepted, which is displayed by the illumination light; a light-emitting element arranged on the rear side of the light guide plate and which emits sensor light in a direction parallel to the rear surface of the light guide plate; and a light-emitting element arranged on the rear side of the light guide plate, which emits sensor light in a direction parallel to the rear surface of the light guide plate, and a light-emitting element that emits sensor light in a direction parallel to the rear surface of the light guide plate and is reflected or scattered by a predetermined object located at the position where the operation input is to be accepted. a control unit that, upon receiving the detection signal from the detection unit, outputs a signal indicating that an operation input has been performed, and changes the lighting state of the first light source and changes the color of the illumination light from the second light source; a first reflecting member that reflects the sensor light emitted from the light-emitting element of the detection unit so that the sensor light passes through the light guide plate, the transmissive region, and the three-dimensional display unit toward a position where the operation input is accepted, and has a reflective surface that is formed in a convex shape relative to the light-emitting element; and a second reflecting member that reflects or scatters the sensor light that has passed through the three-dimensional display unit, the transmissive region, and the light guide plate toward the detection unit, and has a reflective surface that is formed in a concave or flat shape relative to the light-receiving element, With this configuration, the contactless switch can clarify the position where operation input is accepted. Furthermore, the contactless switch has a wide range where the sensor light reaches by the first reflecting member, and the second reflecting member directs the reflected or scattered sensor light to the light-receiving element of the detection unit without diffusing it, so that it can detect user operations with high sensitivity. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a non-contact switch according to an embodiment of the present invention; [Figure 2] 1 is a side cross-sectional view of a non-contact switch according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic front view of the mask sheet. [Figure 4] FIG. 10 is a schematic configuration diagram of a non-contact switch according to a modified example. [Figure 5] FIG. 10 is a schematic configuration diagram of a non-contact switch according to another modified example. [Figure 6] 6A and 6B are diagrams showing other forms of the mirror sheet in the modified example shown in FIG. 5. [Figure 7] 10(a) and 10(b) are schematic side cross-sectional views of a non-contact switch according to still another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] A non-contact switch according to an embodiment of the present invention will be described below with reference to the drawings. This non-contact switch is capable of displaying a three-dimensional image indicating a position where an operational input is accepted on the side facing the user (hereinafter, for convenience of explanation, this may be referred to as the front side). It is also capable of displaying a predetermined pattern indicating the position where an operational input is accepted using illumination light guided by a light guide plate. This non-contact switch transmits sensor light from an optical sensor located on the side of the light guide plate opposite the side facing the user (hereinafter, for convenience of explanation, this may be referred to as the back side), which guides the illumination light, to the front side, and detects the sensor light reflected or scattered by the user's finger or the like, thereby detecting an operational input by the user. This non-contact switch also includes a light-shielding portion between the three-dimensional display unit for displaying the three-dimensional image and the light guide plate, which blocks the sensor light and illumination light in areas other than the transparent region where the predetermined pattern is provided. This makes the predetermined pattern more visible, thereby clarifying the position where an operational input is accepted.

[0010] In the embodiment described below, the non-contact switch is operated by a user's finger. That is, the operation input is accepted by detecting sensor light reflected or scattered by a user's finger placed at a position where the operation input is accepted. The user's finger is an example of a predetermined object for making an operation input to the non-contact switch. However, the predetermined object for making an operation input is not limited to the user's finger, but may be another part of the user, such as the user's hand, or an object worn by or held by the user that can reflect or scatter sensor light.

[0011] FIG. 1 is a schematic diagram of a non-contact switch according to an embodiment of the present invention. FIG. 2 is a side cross-sectional view of the non-contact switch according to an embodiment of the present invention. The non-contact switch 1 includes a 3D display unit 11, a mask sheet 12, a light guide plate 13, an optical sensor 14, a first light source 15, a second light source 16, and a control unit 17. These components are housed in a housing 18. Among these components, the 3D display unit 11, the mask sheet 12, the light guide plate 13, and the optical sensor 14 are arranged in this order from the front side to the rear side. The first light source 15 is arranged to face the incident surface 11a formed on the side of the 3D display unit 11. Similarly, the second light source 16 is arranged to face the incident surface 13a formed on the side of the light guide plate 13. The control unit 17 controls the first light source 15 and the second light source 16 based on the detection result of the optical sensor 14. Each component of the non-contact switch 1 will be described in detail below.

[0012] The 3D display unit 11 uses light emitted from the first light source 15 and incident on the incident surface 11a to display a 3D image 21 in midair on the front side of the 3D display unit 11 near the position where operational input is accepted. The 3D image 21 indicates the position where operational input is accepted. Furthermore, the 3D display unit 11 is configured so that a pattern 22 indicating the position where operational input is accepted, which is arranged on the rear side of the 3D display unit 11, can be seen from the front side. To this end, the 3D display unit 11 is configured as a light guide plate formed into a plate shape by molding a material that is transparent to visible light, such as an optical resin such as polymethyl methacrylate (PMMA), polycarbonate, or cycloolefin polymer. The rear side of the 3D display unit 11 is provided with multiple prisms (not shown) formed as triangular prism-shaped grooves and arranged at different positions for each point of the 3D image 21 displayed in midair. One surface of each prism faces the first light source 15 and is formed as a reflective surface that totally reflects light incident on the incident surface 11a and propagating through the 3D display unit 11 toward the front side. For each point of the 3D image 21 displayed in midair, each of the multiple prisms corresponding to that point is positioned so as to reflect the light incident on the incident surface 11a and propagating through the 3D display unit 11 toward that point. Therefore, light from multiple prisms positioned at different positions converges on each point of the 3D image 21 displayed in midair. Therefore, from a user positioned in front, each point of the 3D image displayed in midair appears to emit light. Therefore, the 3D image 21 displayed in midair is observed by the user.

[0013] While the first light source 15 is on, the stereoscopic image is displayed by the stereoscopic display unit 11. On the other hand, when the first light source 15 is turned off, the stereoscopic display unit 11 no longer displays the stereoscopic image. Therefore, as will be described in detail later, the control unit 17 switches between turning on and off the first light source 15 based on the detection result of the optical sensor 14, thereby switching whether or not the stereoscopic image is displayed. Therefore, the user can identify the operation state of the non-contact switch 1 depending on whether or not the stereoscopic image is displayed.

[0014] The mask sheet 12 is an example of a light-shielding section, and is a sheet-like member that is placed between the three-dimensional display section 11 and the light guide plate 13. The mask sheet 12 displays a pattern 22 that indicates the position where operation input is accepted using illumination light from the second light source 16, and also blocks the illumination light traveling from the back side to the front side and the sensor light from the optical sensor 14 from areas other than the pattern 22.

[0015] FIG. 3 is a schematic front view of the mask sheet 12. The mask sheet 12 is made of an opaque material that blocks the sensor light from the optical sensor 14 and the light from the second light source 16. A pattern 22 is provided near a position where an operation input is accepted, for example, so as to overlap with the foot of a perpendicular line drawn from a predetermined point on the three-dimensional image 21 (for example, the center of gravity of the three-dimensional image 21) to the mask sheet 12. The pattern 22 is formed, for example, in a transparent region 12a provided by cutting out the mask sheet 12 so as to transmit the sensor light from the optical sensor 14 and the illumination light from the second light source 16, by applying a material that is opaque to the illumination light, such as ink or paint, to the front surface of the light guide plate 13. This allows the user to view the pattern 22 when the second light source 16 is turned on. Note that the material forming the pattern 22 is preferably a material that does not transmit the illumination light from the second light source 16 but transmits the sensor light from the optical sensor 14. For example, if the sensor light is infrared light, infrared-transmitting ink is preferably used. Alternatively, the periphery of the pattern 22 in the transmissive region 12a may be covered with a material that blocks the illumination light from the second light source 16 but transmits the sensor light from the optical sensor 14, and the pattern 22 itself may be formed to transmit both the illumination light and the sensor light. This prevents the pattern 22 itself from blocking the sensor light, thereby preventing the optical sensor 14 from failing to detect the user's finger even when the user moves their finger to or near a position that accepts operational input. Furthermore, the periphery of the transmissive region 12a is formed as a light-shielding region 12b that blocks the illumination light and the sensor light. This blocks illumination light and stray light traveling from the back side to the front side of the mask sheet 12 except around the pattern 22, making it easier for the user to see the pattern 22 and the three-dimensional image, and as a result, making it easier for the user to understand the position where operational input is accepted.

[0016] The light guide plate 13 is a plate-shaped member formed by molding an optical resin such as polymethyl methacrylate (PMMA), polycarbonate, or cycloolefin polymer, which is transparent to visible light, and is placed on the back side of the mask sheet 12.

[0017] An incident surface 13a facing the second light source 16 is formed on one side of the light guide plate 13. Furthermore, a plurality of prisms are formed on the rear surface of the light guide plate 13 for totally reflecting light propagating within the light guide plate 13 toward the front side. Each prism is formed, for example, as a triangular prism-shaped groove. Therefore, illumination light emitted from the second light source 16 and entering the light guide plate 13 from the incident surface 13a propagates while being totally reflected between the front and rear surfaces of the light guide plate 13, and is then totally reflected by one of the prisms provided on the rear side of the light guide plate 13 and emitted from the front side. Of the emitted light, the illumination light that passes through the transmission region 12a of the mask sheet 12 illuminates the pattern 22 from the rear side and further passes through the stereoscopic display unit 11. Therefore, when the second light source 16 is turned on, the user can see the pattern 22.

[0018] The optical sensor 14 is an example of a detection unit, and is disposed on the rear side of the light guide plate 13. It detects a user's operation input. To this end, the optical sensor 14 has a light-emitting element (not shown) that emits sensor light and a light-receiving element (not shown) that detects the sensor light reflected or scattered by the user's finger and outputs a detection signal indicating that the sensor light has been detected. The sensor light is preferably invisible to the user, and therefore the light-emitting element may be, for example, an infrared-emitting diode that emits infrared light as the sensor light. The light-receiving element may be a light-receiving element that is sensitive to the sensor light, for example, a photodiode that is sensitive to infrared light.

[0019] In this embodiment, the optical sensor 14 is attached to the side of the housing 18 so that the sensor light emitted from the light-emitting element travels in a direction substantially parallel to the rear surface of the light guide plate 13, as indicated by line 201 in FIG. 2 . The direction of the sensor light can be the direction of the highest intensity in the intensity distribution of the sensor light emitted from the light-emitting element of the optical sensor 14. Arranging the optical sensor 14 in this manner enables the non-contact switch 1 to be made thinner. The sensor light emitted from the light-emitting element is specularly reflected by a mirror sheet 181 provided on the bottom surface of the housing 18, passes through the light guide plate 13, and then passes through the transparent region 12a of the mask sheet 12 and the 3D display unit 11 to travel to a position on the front side of the 3D display unit 11 that accepts operational input. The mirror sheet 181 is an example of a reflective member. When the user brings his / her finger close to the position where the operation input is accepted, a portion of the sensor light reflected or scattered by the user's finger passes through the stereoscopic display unit 11, the transmissive region 12a of the mask sheet 12, and the light guide plate 13 again, and is then specularly reflected by the mirror sheet 181 and returned to the optical sensor 14. When the light receiving element of the optical sensor 14 detects the returned sensor light, it outputs a detection signal to the control unit 17. This detects the operation input by the user. Note that in this example, the path taken by the sensor light emitted from the light-emitting element and the path taken by the sensor light detected by the light receiving element are approximately the same, so the position where the operation input is accepted may be set on the path taken by the sensor light in the air on the front side of the stereoscopic display unit 11.

[0020] First light source 15 has a light-emitting element such as a light-emitting diode that emits light of a predetermined emission color, and is arranged so that the light-emitting surface of the light-emitting element faces incident surface 11a of stereoscopic display unit 11. The light emitted from first light source 15 enters stereoscopic display unit 11 from incident surface 11a, propagates within stereoscopic display unit 11, and is reflected by each of a plurality of prisms provided on the back surface of stereoscopic display unit 11 to exit from the front side of stereoscopic display unit 11, forming stereoscopic image 21 near the position where operation input is accepted.

[0021] The first light source 15 is turned on or off in response to a control signal from the control unit 17. That is, when the stereoscopic image 21 is projected into the air, the first light source 15 is turned on. On the other hand, when the first light source 15 is turned off, the stereoscopic image 21 becomes invisible.

[0022] The second light source 16 emits illumination light that illuminates the pattern 22. To this end, the second light source 16 has two or more light-emitting elements that emit different colors of light (for example, a first light-emitting element that emits blue light and a second light-emitting element that emits red light). That is, the second light source 16 is capable of changing the color of the illumination light. Each light-emitting element may be, for example, a light-emitting diode. The illumination light emitted from each light-emitting element of the second light source 16 enters the light guide plate 13 from the incident surface 13a, propagates through the light guide plate 13, and is reflected by multiple prisms provided on the back surface of the light guide plate 13 to exit from the front side of the light guide plate 13 and illuminate the pattern 22 provided on the mask sheet 12.

[0023] The light-emitting elements of second light source 16 are controlled in response to a control signal from control unit 17 so that some light-emitting elements are turned on and the other light-emitting elements are turned off. That is, the color of the illumination light that illuminates pattern 22 changes depending on which light-emitting element of second light source 16 is emitting light. Therefore, control unit 17 switches the light-emitting element that is to emit light every time it receives an operation input from the user, making it easy for the user to identify the operation state of non-contact switch 1.

[0024] When the control unit 17 receives a detection signal from the optical sensor 14, it outputs a signal indicating that an operation input has been performed, and also changes the lighting state of the first light source 15 and changes the color of the illumination light emitted from the second light source 16. To this end, the control unit 17 has, for example, one or more microprocessors, a semiconductor memory, and an interface for connecting to other devices.

[0025] When no operation input by the user is accepted, control unit 17 turns on first light source 15, turns on one of the light-emitting elements (for example, the first light-emitting element that emits blue light) of second light source 16, and turns off the other light-emitting elements. As a result, a three-dimensional image 21 is displayed in the air near the position where the operation input is accepted, and a pattern 22 illuminated with illumination light having the emission color of the first light-emitting element is displayed.

[0026] Thereafter, when the control unit 17 receives a detection signal from the optical sensor 14, it outputs a signal indicating that the operation state has become a first state (e.g., an on state) to another device via the interface. The control unit 17 then turns off the first light source 15. As a result, the stereoscopic image 21 is no longer displayed. The control unit 17 also turns off the first light-emitting element of the second light source 16 and turns on the other light-emitting element (e.g., the second light-emitting element that emits red light). As a result, the color of the illumination light illuminating the pattern 22 changes (e.g., the color of the illumination light changes from the color emitted by the first light-emitting element to the color emitted by the second light-emitting element). This allows the user to easily recognize that the operation input has been accepted and the operation state has changed.

[0027] Thereafter, when the control unit 17 receives a detection signal again after temporarily stopping receiving the detection signal from the optical sensor 14, it outputs a signal to the other device via the interface indicating that the operation state has changed to the second operation state (e.g., the off state). The control unit 17 then turns on the first light source 15 again. This causes the three-dimensional image 21 to be displayed again. The control unit 17 also turns off the second light-emitting element and turns on the first light-emitting element among the light-emitting elements of the second light source 16. This causes the color of the illumination light illuminating the pattern 22 to change from the color emitted by the second light-emitting element to the color emitted by the first light-emitting element. Therefore, the user can easily recognize that the operation input has been accepted again and the operation state has returned to the original state.

[0028] As described above, this non-contact switch can detect an input by a user moving their finger to a position in the air where the input is accepted, allowing the user to operate a device incorporating the non-contact switch without contact. Furthermore, this non-contact switch changes the presence or absence of a stereoscopic image and the illumination color of the pattern indicating the position where the input is accepted each time the switch accepts an input, allowing the user to easily determine whether the input has been accepted. Furthermore, this non-contact switch has a mask sheet positioned in front of a light guide plate that illuminates the pattern indicating the position where the input is accepted, thereby blocking illumination light and stray light traveling from the back side to the front side except around the pattern. Therefore, this non-contact switch can easily visually recognize the pattern regardless of the operation state. As a result, this non-contact switch can clearly indicate the position where the input is accepted.

[0029] According to a variant, the contactless switch may be configured to perform the functions of several switches independent of one another.

[0030] Fig. 4 is a schematic diagram of a non-contact switch according to this modification. The non-contact switch 2 according to this modification differs from the non-contact switch 1 shown in Figs. 1 and 2 in that it has three switches and displays a pattern and a three-dimensional image for each switch. Therefore, the following describes these differences and related parts of the non-contact switch 2. Also, in Fig. 4, components unrelated to the differences are omitted from the illustration.

[0031] In this modification, the non-contact switch 2 has three switches. To this end, the 3D display unit 11 is configured to form three 3D images 21-1 to 21-3 in the air using light from the first light source 15. Each of the 3D images 21-1 to 21-3 is displayed near a position where an operation input for a corresponding one of the three switches is accepted. To form the three 3D images 21-1 to 21-3, the 3D display unit 11 may be formed as a light guide plate, as in the above embodiment, and may have a plurality of prisms on its rear surface that totally reflect light emitted from the first light source 15 and entering the 3D display unit 11 so that the light exits from the front surface. Each of the 3D images 21-1 to 21-3 is displayed by a plurality of prisms that correspond to individual points on the 3D image and are positioned differently from one another, and that direct the light from the first light source 15 that enters the 3D display unit 11 toward the corresponding point.

[0032] In this modification, the first light source 15 has a light-emitting element for each of the three-dimensional images 21-1 to 21-3, and each light-emitting element is arranged to face a different side surface of the three-dimensional display unit 11. Each side surface of the three-dimensional display unit 11 is configured as an incident surface. The prism corresponding to each point of each of the three-dimensional images 21-1 to 21-3 is arranged so that the light-emitting element corresponding to that three-dimensional image faces the reflecting surface. This allows the control unit 17 to control the lighting and extinguishing of the corresponding light-emitting element for each switch depending on the operation state of that switch, thereby independently changing whether or not to display a three-dimensional image for each switch.

[0033] Furthermore, patterns 22-1 to 22-3 are formed on the mask sheet 12, indicating positions at which operation inputs are accepted for each switch. Each of the patterns 22-1 to 22-3 is disposed at a position overlapping with the foot of a perpendicular line extending from a predetermined point (e.g., the center of gravity) of the corresponding three-dimensional image toward the front of the mask sheet 12. The patterns 22-1 to 22-3 may be the same pattern or may be different from each other. Each of the patterns 22-1 to 22-3 is illuminated from the rear side by illumination light emitted from the second light source 16 and propagated through the light guide plate 13, thereby becoming visible to the user. In this modification, the second light source 16 has light-emitting elements with different emission colors for each of the patterns 22-1 to 22-3, and the light-emitting elements of each pattern are disposed so as to face different side surfaces of the light guide plate 13. Each side surface is configured as an incident surface. The prism corresponding to each of patterns 22-1 to 22-3 is arranged so that the light emitting element corresponding to that pattern faces the reflective surface. This allows control unit 17 to control the lighting and extinguishing of the corresponding light emitting element for each switch according to the operation state of that switch, thereby making it possible to change the color of the illumination light that illuminates the pattern for each switch independently.

[0034] Furthermore, in the non-contact switch 2 according to this modification, optical sensors 14-1 to 14-3 are provided for each switch. Similar to the optical sensor 14 according to the above embodiment, each of the optical sensors 14-1 to 14-3 includes a light-emitting element and a light-receiving element. The sensor light emitted from the light-emitting element of each of the optical sensors 14-1 to 14-3 is reflected by the mirror sheet 181, passes through the light guide plate 13, the corresponding patterned transmissive area on the mask sheet 12, and the 3D display unit 11, and travels toward the position where the corresponding switch accepts an operational input. Furthermore, for each switch, the sensor light reflected or scattered by the user's finger placed at the position where the switch accepts an operational input passes through the 3D display unit 11, the corresponding transmissive area on the mask sheet 12, and the light guide plate 13, is reflected by the mirror sheet 181, and is received by the light-receiving element of the corresponding optical sensor. This allows the operational input to be accepted for each switch.

[0035] As in the above embodiment, for each switch, each time an operational input to that switch is detected, the control unit 17 controls the light-emitting elements of the first light source 15 and the second light source 16 corresponding to that switch to change whether or not a stereoscopic image is displayed and the illumination light pattern, and outputs a signal indicating the operational status of that switch to other devices.

[0036] According to this modified example, the non-contact switch can realize multiple switches, and changes whether or not to display a three-dimensional image and the lighting color of the pattern depending on the operation input received for each switch, making it easier for the user to understand which switch has been operated.

[0037] According to another variant, the light emitting element and the light receiving element of the optical sensor may be arranged at different positions.

[0038] Fig. 5 is a schematic diagram of a non-contact switch according to this modification. The non-contact switch 3 according to this modification differs from the non-contact switch 1 shown in Figs. 1 and 2 in the configuration of the optical sensor. Therefore, the following describes these differences and related parts of the non-contact switch 3. Also, in Fig. 5, components unrelated to the differences are omitted from the illustration.

[0039] In this modification, the light-emitting element 141 and the light-receiving element 142 of the optical sensor 14 are disposed at different positions. For example, the light-emitting element 141 and the light-receiving element 142 are disposed in a direction along the incident surface 13a of the light guide plate 13 so that a position for accepting an operation input, a three-dimensional image 21 displayed by the three-dimensional display unit 11, and a pattern 22 provided on the mask sheet 12 are located between the light-emitting element 141 and the light-receiving element 142.

[0040] Two mirror sheets 181 and 182 are formed on the housing 18. The mirror sheet 181 is formed so as to specularly reflect, at a position from the light-emitting element 141 along the normal direction of the incident surface 13a, the sensor light emitted from the light-emitting element 141 toward a position on the front side of the non-contact switch 3 that accepts an operation input. That is, the reflective surface of the mirror sheet 181 is tilted toward the display position of the stereoscopic image 21 and the light-receiving element 142 rather than facing the light-emitting element 141 directly. On the other hand, the mirror sheet 182 is formed so as to specularly reflect, at a position from the light-receiving element 142 along the normal direction of the incident surface 13a, the sensor light that has been reflected or scattered by the user's finger and transmitted through the stereoscopic display unit 11, the transmission region of the mask sheet 12, and the light guide plate 13 toward the light-receiving element 142. That is, the reflective surface of the mirror sheet 182 is tilted toward the display position of the stereoscopic image 21 and the light-emitting element 141 rather than facing the light-receiving element 142 directly. Therefore, in this modification, the position where the operation input is accepted is a position where the direction of the sensor light reflected by the mirror sheet 181 (indicated by arrow 501) intersects with the direction of the sensor light reflected or scattered by the user's finger and reflected by the mirror sheet 182 (indicated by arrow 502) toward the position where the light receiving element 142 can receive the light. As a result, the position P where the operation input is accepted is more limited than in the above embodiment. This prevents the operation of the non-contact switch 3 from being erroneously detected when the user approaches the non-contact switch 3 without intending to operate it. Note that in this modification, in order to prevent the user from accidentally touching the non-contact switch 3, it is preferable that the position P where the operation input is accepted be set so that the distance between the position P where the operation input is accepted and the 3D display unit 11 is greater than the distance from the 3D display unit 11 to the position where the 3D image 21 is displayed. The distance from the stereoscopic display unit 11 to the position P where the operation input is accepted is determined by the distance between the light-emitting element 141 and the light-receiving element 142 of the optical sensor 14 and the angle formed by the reflective surfaces of the mirror sheets 181 and 182 with respect to the bottom surface of the housing 18.Therefore, the distance between the light-emitting element 141 and the light-receiving element 142 of the optical sensor 14 and the angle formed by the reflective surfaces of the mirror sheets 181 and 182 with respect to the bottom surface of the housing 18 may be adjusted so as to set the position at which the operational input is accepted as described above.

[0041] FIG. 6 is a diagram showing another form of the mirror sheet in the modified example shown in FIG. 5. In this modified example, mirror sheet 181, which reflects sensor light from light-emitting element 141 of optical sensor 14 toward the position where operational input is accepted, is formed so that its reflective surface is convex with respect to light-emitting element 141. In contrast, mirror sheet 182, which reflects sensor light incident on non-contact switch 3 from the position where operational input is accepted toward light-receiving element 142 of optical sensor 14, is formed so that its reflective surface is concave with respect to light-receiving element 142. In particular, mirror sheet 182 is preferably formed so that the focal length of the reflective surface on the concave surface is such that the center of the range where operational input is accepted and light-receiving element 142 form an imaging relationship. As a result, sensor light reflected by mirror sheet 181 is diffused, thereby widening the range where operational input is accepted. On the other hand, the sensor light that is reflected or scattered by a user's finger positioned within the range where operation input is accepted and that enters the non-contact switch 3 is collected by the mirror sheet 182, so that the light receiving element 142 can detect the sensor light with higher sensitivity. Therefore, the non-contact switch 3 according to this modification can detect user operations with higher sensitivity. Note that the reflective surface of the mirror sheet 182 that directs the sensor light that has entered the non-contact switch 3 toward the light receiving element 142 may be formed in a flat shape.

[0042] In the above-described embodiment or each modification, a prism may be disposed in place of the mirror sheet for reflecting the sensor light.

[0043] 7(a) and 7(b) are schematic side cross-sectional views of a non-contact switch according to this modification. As shown in FIG. 7(a), according to this modification, a prism 19 having a sector-shaped cross section is disposed on the bottom surface of a housing 18. In this example, the prism 19 is disposed so that one flat surface, i.e., an entrance surface 19a, of the prism 19 faces the light-emitting element of the optical sensor 14, and the other flat surface, i.e., an exit surface 19b, of the prism 19 is parallel to the light guide plate 13. Sensor light emitted from the light-emitting element of the optical sensor 14 enters the prism 19 through the entrance surface 19a, is totally reflected by the curved reflecting surface 19c of the prism 19, and then exits from the exit surface 19b and travels toward the front side of the non-contact switch. Reflecting surface 19c may be formed in a concave shape with respect to optical sensor 14 on a surface that is perpendicular to the bottom surface of housing 18 and along a direction directly facing the light-emitting element of optical sensor 14, and may be formed in a linear shape in a direction parallel to the bottom surface of housing 18, or may be formed in a convex or concave shape with respect to optical sensor 14. Conversely, sensor light that enters the non-contact switch from a position where an operational input is accepted enters prism 19 from exit surface 19b, is totally reflected by reflecting surface 19c, and then exits from entrance surface 19a toward the light-receiving element of optical sensor 14.

[0044] 7(a), the example shown in Fig. 7(b) differs in that the incident surface 19a is inclined toward the bottom surface of the housing 18. In this example, sensor light emitted from the light-emitting element of the optical sensor 14 is refracted by the incident surface 19a and enters the prism 19, is totally reflected by the reflecting surface 19c of the prism 19, and then exits from the exit surface 19b and travels toward the front side of the non-contact switch. Conversely, sensor light that enters the non-contact switch from a position where an operational input is accepted enters the prism 19 from the exit surface 19b, is totally reflected by the reflecting surface 19c, and then exits while refracted by the incident surface 19a and travels toward the light-receiving element of the optical sensor 14.

[0045] 7(a) and 7(b), the sensor light is redirected by total reflection, which reduces loss of the sensor light, allowing the non-contact switch to sensitively detect user operations.

[0046] At least one of the entrance surface 19a and the exit surface 19b of the prism 19 may be formed as a lens surface having positive refractive power. In this case, the lens surface may be formed as a Fresnel lens surface or a diffractive lens. This makes it possible to focus the sensor light emitted from the light-emitting element of the optical sensor 14 near the position where an operational input is accepted, or to focus the sensor light reflected or scattered by a user's finger placed at the position where an operational input is accepted near the light-receiving element of the optical sensor 14. This allows the non-contact switch to detect user operations with higher sensitivity.

[0047] As described above, those skilled in the art can make various modifications to the embodiments within the scope of the present invention. [Explanation of symbols]

[0048] 1, 2, 3 non-contact switch 11 3D display section 11a Incidence plane 12 mask sheets 12a Transparent area 12b Shading area 13 Light guide plate 13a Incidence plane 14, 14-1 to 14-3 Optical sensors 141 Light-emitting element 142 Photodetector 15 First Light Source 16 Second Light Source 17 Control Unit 18 Case 181, 182 mirror sheet 19 Prism 21, 21-1~21-3 Stereoscopic image 22, 22-1 to 22-3 patterns

Claims

[Claim 1] a first light source; a three-dimensional display unit that is capable of visually recognizing, from the front side, a pattern that indicates a position where an operation input is accepted and that is arranged on the rear side, and that is capable of displaying a three-dimensional image that indicates the position using light emitted from the first light source; a second light source that emits illumination light whose emission color is changeable; a light guide plate disposed on the rear side of the stereoscopic display unit and directing the illumination light emitted from the second light source toward the stereoscopic display unit; a light-shielding section disposed between the three-dimensional display section and the light guide plate, the light-shielding section having a light-shielding region that blocks sensor light and the illumination light and a light-transmitting region that transmits the sensor light and the illumination light, wherein a pattern that indicates the position and is displayed by the illumination light is formed in the light-transmitting region; a detection unit that is disposed on the rear side of the light guide plate and that has a light emitting element that emits the sensor light in a direction parallel to the rear surface of the light guide plate, and a light receiving element that, when detecting the sensor light reflected or scattered by a predetermined object at the position, outputs a detection signal that indicates the detection; a control unit that, upon receiving the detection signal from the detection unit, outputs a signal indicating that the operation input has been performed, and changes the lighting state of the first light source and changes the color of the illumination light of the second light source; a first reflecting member that reflects the sensor light emitted from the light-emitting element of the detection unit so that the sensor light passes through the light guide plate, the transmission area, and the three-dimensional display unit toward the position, and that has a reflection surface that is formed in a convex shape with respect to the light-emitting element; a second reflecting member that reflects the sensor light that is reflected or scattered by the predetermined object at the position and that has passed through the three-dimensional display unit, the transmission area, and the light guide plate toward the detection unit, and that has a reflection surface that is formed in a concave or planar shape relative to the light receiving element; A non-contact switch having a

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