Display device

Abstract

The present invention provides a display device with which a user can visually recognize an image displayed on an edge terminal as a virtual image. A display device according to the present disclosure comprises: a terminal holding part that detachably holds an edge terminal; and an optical system that forms an image of image light emitted from the edge terminal as a virtual image in the user's field of view.

Description

display device

[0001] The present disclosure relates to a display device.

[0002] Various display devices have been proposed that are attached to the back of the front seats of a vehicle and allow passengers seated in the rear seats to view images displayed on a liquid crystal panel as enlarged virtual images (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 2005-67555

[0004] The display device of the present disclosure includes a terminal holder that detachably holds an edge terminal, and an optical system that forms image light emitted from the edge terminal as a virtual image within the user's field of view.

[0005] FIG. 1 is a schematic diagram illustrating a display device according to the present disclosure mounted on a vehicle. FIG. 2 is a schematic diagram illustrating a configuration of a display device according to the present disclosure. FIG. 3 is a schematic diagram illustrating an example of a terminal holding section of a display device according to the present disclosure. FIG. 4 is a schematic diagram illustrating an example of an optical system of a display device according to a first embodiment. FIG. 5 is a schematic diagram illustrating another example of the optical system of a display device according to the first embodiment. FIG. 6 is a schematic diagram illustrating another example of the configuration of a terminal holding section. FIG. 7 is a schematic diagram illustrating an example of an optical system of a display device according to a second embodiment.

[0006] In recent years, passengers seated in the backseat of a car are increasingly using edge devices such as smartphones and tablets to view video content. Conventional display devices do not allow users to view the video content displayed on the edge device as an enlarged virtual image.

[0007] The display device of the present disclosure can improve user convenience by allowing a user to view an image displayed on an edge terminal as a virtual image. Furthermore, the display device of the present disclosure can project an image displayed on an edge terminal as a virtual image located behind the display device within the user's field of view, thereby reducing the risk of the user feeling oppressed and improving user comfort and convenience.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The drawings used in the following description are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones. The drawings used in the following description show the main components of the display device of the present disclosure. The display device of the present disclosure may include well-known components not shown, such as wiring that connects the components of the display device to each other and holding members that hold each optical member of the optical system. Also, in some of the drawings, a Cartesian coordinate system XYZ is defined for convenience. The X-axis direction is also referred to as the width direction. The Y-axis direction is also referred to as the height direction. The Z-axis direction is also referred to as the depth direction or the emission direction.

[0009] Fig. 1 is a schematic diagram illustrating a display device of the present disclosure mounted on a vehicle, Fig. 2 is a schematic diagram illustrating the configuration of the display device of the present disclosure, and Fig. 3 is a schematic diagram illustrating an example of a terminal holder of the display device of the present disclosure. Fig. 4 is a schematic diagram illustrating an example of an optical system of the display device according to the first embodiment, and Fig. 5 is a schematic diagram illustrating another example of the optical system of the display device according to the first embodiment. Fig. 6 is a schematic diagram illustrating another example of the configuration of the terminal holder. In Figs. 4 and 5, for ease of illustration, the optical path of the image light incident on the semi-transparent mirror and the optical path of the image light reflected by the semi-transparent mirror are shifted in the Y-axis direction.

[0010] The display device 1 of this embodiment is mounted on a vehicle 16 such as an automobile. As shown in Fig. 1 , the display device 1 is attached to the back of a front seat of the vehicle 16, and allows a user 15 seated in a rear seat to view a virtual image V.

[0011] 2 , the display device 1 may include a terminal holding unit 3 and an optical system 4. The display device 1 may further include a drive unit 5 and a control unit 6.

[0012] The terminal holding unit 3 may detachably hold the edge terminal 2. The edge terminal 2 is an electronic device connected to a network, and may be, for example, a smartphone terminal (hereinafter simply referred to as a smartphone), a tablet terminal (hereinafter simply referred to as a tablet), a phablet terminal, or the like. The edge terminal 2 has a display surface 2a that displays an image, and emits image light from the display surface 2a in the depth direction (Z-axis direction). The image displayed on the display surface 2a may be a moving image or a still image.

[0013] As shown in FIG. 3 , the terminal holding unit 3 may include a left-end holding unit 3a, a right-end holding unit 3b, and a bottom-end holding unit 3c. The left-end holding unit 3a, the right-end holding unit 3b, and the bottom-end holding unit 3c may have grooves that receive the outer edges of the edge terminal 2. When using the display device 1, the user 15 manually inserts the edge terminal 2 between the left-end holding unit 3a and the right-end holding unit 3b from above the terminal holding unit 3 and abuts it against the bottom-end holding unit 3c. This secures the edge terminal 2 to the terminal holding unit 3. When the user 15 has finished using the display device 1, they can manually remove the edge terminal 2 from the terminal holding unit 3.

[0014] The terminal holding unit 3 may be configured so that one of the left end holding unit 3a and the right end holding unit 3b is relatively movable toward the other. In this case, the terminal holding unit 3 can grip the edge terminal 2 in the width direction (X-axis direction). The left end holding unit 3a and / or the right end holding unit 3b may be moved manually by the user 15 or by the drive unit 5.

[0015] The edge terminal 2 may emit linearly polarized image light in the Z-axis direction (emission direction). The edge terminal 2 may emit linearly polarized image light having a polarization axis in a first direction. The linearly polarized light having a polarization axis in the first direction may be S-wave polarized light. Below, a case will be described in which the edge terminal 2 emits S-wave polarized image light, but this is not limited to this, and the edge terminal 2 may also emit P-wave polarized image light.

[0016] The display device 1 may be configured so that linearly polarized image light having a polarization axis in a first direction is incident on the optical system 4, and the edge terminal 2 may not emit linearly polarized image light. The display device 1 may include, for example, a polarizing element located between the edge terminal 2 and the optical system 4, which transmits linearly polarized light having a polarization axis in the first direction. The polarizing element may include, for example, a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light range. The substrate may be made of, for example, a resin material, a glass material, or the like. The resin material may be, for example, an acrylic resin, a polycarbonate resin, or the like. The thin metal wires may be made of a metal material such as aluminum, chromium, or titanium oxide. The polarizing element can transmit polarized light vibrating in a direction perpendicular to the grid and reflect polarized light vibrating in a direction parallel to the grid.

[0017] The optical system 4 may project an image displayed on the display surface 2 a of the edge terminal 2 as a virtual image V into the field of view of the user 15 .

[0018] The display device 1 can allow the user 15 to view the image displayed on the edge terminal 2 as a virtual image V, thereby improving the convenience of the user 15. Furthermore, the display device 1 can project the image displayed on the edge terminal 2 into the field of view of the user 15 as a virtual image V located further back than the display device 1, thereby reducing the risk that the user 15 will feel a sense of oppression and improving the comfort and convenience of the user 15.

[0019] Next, the configuration of the optical system 4 will be described. As shown in Fig. 4 , the optical system 4 may include a first semi-transparent mirror 7, a second semi-transparent mirror 8, a third semi-transparent mirror 9, a first retardation plate 10, and a second retardation plate 11. The second semi-transparent mirror 8, the first retardation plate 10, the first semi-transparent mirror 7, the second retardation plate 11, and the third semi-transparent mirror 9 may be arranged in this order in the emission direction (Z-axis direction) of the image light from the edge terminal 2.

[0020] The first semi-transmitting mirror 7 may be located away from the display surface 2a of the edge terminal 2 in the emission direction of the image light. The first semi-transmitting mirror 7 may transmit a portion (approximately 50%) of the incident light and reflect the remaining portion (approximately 50%). The first semi-transmitting mirror 7 may have a reflective surface 7a facing the first retardation plate 10 and a reflective surface 7b facing the second retardation plate 11. The first semi-transmitting mirror 7 may be a plane mirror (plane half mirror) whose reflective surfaces 7a and 7b are parallel or approximately parallel to the display surface 2a of the edge terminal 2.

[0021] The first semi-transparent mirror 7 may be configured to include, for example, a substrate and a semi-transparent layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be configured from, for example, inorganic glass, a resin material, or the like. The resin material may be, for example, an acrylic resin, a polycarbonate resin, or the like. The semi-transparent layer may be a metal thin film. The metal thin film may be configured from a metal material such as aluminum, chromium, or the like. The semi-transparent layer is not limited to a metal thin film and may be, for example, a dielectric multilayer film, or the like.

[0022] The first retardation plate 10 may be located between the edge terminal 2 and the first semi-transparent mirror 7. The second retardation plate 11 may be located on the opposite side of the first semi-transparent mirror 7 from the first retardation plate 10. The first retardation plate 10 and the second retardation plate 11 may be quarter-wave plates. The first retardation plate 10 and the second retardation plate 11 may be fixed to the first semi-transparent mirror 7 by an optically transparent adhesive such as an optically clear adhesive (OCA). The adhesive may be a material with small retardation (phase difference).

[0023] The second semi-transmitting mirror 8 may be located between the edge terminal 2 and the first retardation plate 10. The second semi-transmitting mirror 8 may transmit a portion of the incident light and reflect the remainder. The second semi-transmitting mirror 8 may transmit polarized light having a polarization axis in a first direction (S-wave polarized light in this embodiment) and reflect polarized light having a polarization axis in a second direction orthogonal to the first direction (P-wave polarized light in this embodiment). The second semi-transmitting mirror 8 may be a concave mirror having a concave reflecting surface 8a facing the reflecting surface 7a of the first semi-transmitting mirror 7 via the first retardation plate 10. At least a portion of the reflecting surface 8a of the second semi-transmitting mirror 8 may include a spherical shape, an aspherical shape, or a free-form surface shape.

[0024] The second semi-transparent mirror 8 may be configured to include, for example, a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be configured from, for example, a resin material, a glass material, or the like. The resin material may be, for example, an acrylic resin, a polycarbonate resin, or the like. The thin metal wires may be configured from a metal material, for example, aluminum, chromium, titanium oxide, or the like. The second semi-transparent mirror 8 can transmit polarized light oscillating in a direction perpendicular to the grid and can reflect polarized light oscillating in a direction parallel to the grid.

[0025] The third semi-transmitting mirror 9 may be located on the opposite side of the first semi-transmitting mirror 7, the first retardation plate 10, and the second retardation plate 11 from the second semi-transmitting mirror 8. The third semi-transmitting mirror 9 may transmit a portion of the incident light and reflect the remainder. The third semi-transmitting mirror 9 may reflect polarized light having a polarization axis in a first direction (S-wave polarized light in this embodiment) and transmit polarized light having a polarization axis in a second direction orthogonal to the first direction (P-wave polarized light in this embodiment). The third semi-transmitting mirror 9 may be a concave mirror having a concave reflecting surface 9a facing the reflecting surface 7b of the first semi-transmitting mirror 7 via the second retardation plate 11. At least a portion of the reflecting surface 9a of the third semi-transmitting mirror 9 may include a spherical, aspherical, or free-form surface shape.

[0026] Similar to the second semi-transparent mirror 8, the third semi-transparent mirror 9 may be configured to include a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate.

[0027] A description will be given of the traveling path of the image light incident on the optical system 4. The image light incident on the optical system 4 travels along a path P1 or a path P2 as shown in FIG.

[0028] The light traveling along path P1 will be described. Image light of the first linearly polarized light L1 emitted from the edge terminal 2 passes through the second semi-transparent mirror 8. The first linearly polarized light L1 passes through the first retardation plate 10 and is converted into first circularly polarized light C1. The first circularly polarized light C1 is incident on the first semi-transparent mirror 7. A portion (approximately 50%) of the first circularly polarized light C1 is reflected by the first semi-transparent mirror 7 and converted into second circularly polarized light C2. The second circularly polarized light C2 passes through the first retardation plate 10 and is converted into second linearly polarized light L2, whose polarization axis is orthogonal to the polarization axis of the first linearly polarized light L1. The second linearly polarized light L2 is reflected by the second semi-transparent mirror 8 and is converted into third linearly polarized light L3, whose polarization axis is orthogonal to the polarization axis of the first linearly polarized light L1. The third linearly polarized light L3 passes through the first retardation plate 10 and is converted into third circularly polarized light C3. The third circularly polarized light C3 is incident on the first semi-transparent mirror 7. A portion (approximately 50%) of the third circularly polarized light C3 is transmitted through the first semi-transparent mirror 7. The third circularly polarized light C3 that has transmitted through the first semi-transparent mirror 7 is transmitted through the second retardation plate 11 and converted into fourth linearly polarized light L4 whose polarization axis is perpendicular to the polarization axis of the first linearly polarized light L1. The fourth linearly polarized light L4 is transmitted through the third semi-transparent mirror 9 and emitted to the outside.

[0029] The light traveling along path P2 will be described. The remainder (approximately 50%) of the light of the first circularly polarized light C1 incident on the first semi-transparent mirror 7 is transmitted through the first semi-transparent mirror 7. The light of the first circularly polarized light C1 transmitted through the first semi-transparent mirror 7 is transmitted through the second retardation plate 11 and converted into light of fifth linearly polarized light L5, whose polarization axis is parallel to the polarization axis of the first linearly polarized light L1. The light of the fifth linearly polarized light L5 is reflected by the third semi-transparent mirror 9 and converted into light of sixth linearly polarized light L6, whose polarization axis is parallel to the polarization axis of the first linearly polarized light L1. The light of the sixth linearly polarized light L6 is transmitted through the second retardation plate 11 and converted into light of fourth circularly polarized light C4. The light of the fourth circularly polarized light C4 is incident on the first semi-transparent mirror 7. A portion (approximately 50%) of the light of the fourth circularly polarized light C4 is reflected by the first semi-transparent mirror 7 and converted into light of fifth circularly polarized light C5. The fifth circularly polarized light C5 passes through the second retardation plate 11 and is converted into seventh linearly polarized light L7, the polarization axis of which is orthogonal to the polarization axis of the first linearly polarized light L1. The seventh linearly polarized light L7 passes through the third semi-transparent mirror 9 and is emitted to the outside.

[0030] The image light incident on the optical system 4 travels along path P1 or path P2 and is emitted to the outside. As a result, the amount of image light emitted via the optical system 4 is approximately 50% of the amount of image light incident on the optical system 4. Since the optical system 4 has a relatively high light utilization efficiency, the display device 1 can improve the brightness of the virtual image V viewed by the user.

[0031] In one embodiment of the present disclosure, the first linearly polarized light L1, the fifth linearly polarized light L5, and the sixth linearly polarized light L6 described above may be S-wave polarized light, and the second linearly polarized light L2 to the fourth linearly polarized light L4 and the seventh linearly polarized light L7 may be P-wave polarized light.

[0032] Although the second and third semi-transparent mirrors 8 and 9 have been described above as having polarization selectivity, this is not limiting. The second and third semi-transparent mirrors 8 and 9 may not have polarization selectivity. The second and third semi-transparent mirrors 8 and 9 are half mirrors composed of a substrate and a semi-transparent layer (a semi-transparent layer without polarization selectivity) located on the surface of the substrate, and may transmit a portion (approximately 50%) of incident light and reflect the remaining portion (approximately 50%). In this case, the optical system 4 may include a polarizing plate 18, as shown in FIG. 5 . The polarizing plate 18 may be positioned apart from the third semi-transparent mirror 9 in the output direction (Z-axis direction). The polarizing plate 18 may reflect light whose polarization axis is parallel to the polarization axis of the first linearly polarized light L1 (S-wave polarized light in this embodiment) and transmit light whose polarization axis is orthogonal to the polarization axis of the first linearly polarized light L1 (P-wave polarized light in this embodiment).

[0033] The second semi-transparent mirror 8 and the third semi-transparent mirror 9 are not limited to concave mirrors. The second semi-transparent mirror 8 and the third semi-transparent mirror 9 may be configured as holographic optical elements. In this case, the optical functions of the second semi-transparent mirror 8 and the third semi-transparent mirror 9 can be realized by flat optical members. As a result, the thickness of the second semi-transparent mirror 8 and the third semi-transparent mirror 9 in the depth direction (Z-axis direction) can be reduced, making it possible to miniaturize the optical system 4 in the depth direction. This in turn makes it possible to miniaturize the display device 1 in the depth direction.

[0034] The driving unit 5 may adjust the relative position between a focal point (object focal point) F on the edge terminal 2 side of the optical system 4 and the edge terminal 2. The driving unit 5 may be configured by, for example, an electric slider, an electric cylinder, or the like.

[0035] The drive unit 5 may be configured to be able to adjust the distance between the terminal holding unit 3 that holds the edge terminal 2 and the optical system 4. The drive unit 5 may be configured to be able to adjust the relative positions of the optical members included in the optical system 4, in particular the relative positions of the first semi-transparent mirror 7, the second semi-transparent mirror 8, and the third semi-transparent mirror 9.

[0036] The driver 5 may be configured to be able to adjust the focal lengths of the second semi-transparent mirror 8 and the third semi-transparent mirror 9. The driver 5 may change the focal lengths of the second semi-transparent mirror 8 and the third semi-transparent mirror 9, for example, by deforming the second semi-transparent mirror 8 and the third semi-transparent mirror 9. The driver 5 may change the focal lengths of the second semi-transparent mirror 8 and the third semi-transparent mirror 9, for example, by changing the curvature, shape, etc. of the reflecting surfaces 8 a, 9 a.

[0037] The drive unit 5 may be configured to move the terminal holding unit 3 holding the edge terminal 2 within a plane (X-Y plane) perpendicular to the depth direction (Z-axis direction). The drive unit 5 may be configured to relatively move one of the left end holding unit 3a and the right end holding unit 3b of the terminal holding unit 3 toward the other.

[0038] The control unit 6 may be connected to each component of the display device 1 and control each component. The control unit 6 may be configured to include one or more processors. The processor may include a general-purpose processor configured to load a specific program and execute a specific function, and a dedicated processor specialized for a specific process. The processor may include a programmable logic device (PLD). The control unit 6 may be either a system-on-a-chip (SoC) or a system-in-a-package (SiP) in which one or more processors work together. The control unit 6 may include a memory unit that stores various information, programs for operating each component of the display device 1, etc. The memory unit may be configured, for example, with a semiconductor memory. The memory unit may function as a work memory for the control unit 6.

[0039] The control unit 6 may control the drive unit 5 so that the edge terminal 2 is located closer than the object focus F in the optical system. In other words, the control unit 6 may control the drive unit 5 so that the optical path length of the image light from the edge terminal 2, via the first semi-transparent mirror 7, to the second semi-transparent mirror 8 or the third semi-transparent mirror 9 is shorter than the focal length of the second semi-transparent mirror 8 and the third semi-transparent mirror 9. This allows the display device 1 to project the image displayed on the edge terminal 2 as a virtual image V within the field of view of the user 15, thereby improving the convenience of the user 15. Furthermore, the display device 1 can project the image displayed on the edge terminal 2 as a virtual image V located further back than the display device 1 within the field of view of the user 15. This reduces the risk that the user 15 will feel a sense of oppression, thereby improving the comfort and convenience of the user 15.

[0040] The terminal holding unit 3 may be configured to include one or more processors. The terminal holding unit 3 may be configured to be able to detect the specifications of the edge terminal 2 inserted into the terminal holding unit 3. The specifications of the edge terminal 2 may be, for example, the type, external dimensions, weight, etc. of the edge terminal 2. The terminal holding unit 3 may output the detected specifications of the edge terminal 2 to the control unit 6. The control unit 6 may control the drive unit 5 based on the specifications of the edge terminal 2 acquired from the terminal holding unit 3. The control unit 6 may control the drive unit 5 to change the distance between the edge terminal 2 and the optical system 4 based on the specifications of the edge terminal 2 acquired from the terminal holding unit 3.

[0041] The type of the edge terminal 2 may be, for example, a smartphone, a tablet, or the like. The terminal holding unit 3 may include a weight sensor that detects the weight of the edge terminal 2 inserted into the terminal holding unit 3, and may detect the type of the edge terminal 2 based on the detected weight of the edge terminal 2. For example, the terminal holding unit 3 may determine that the edge terminal 2 is a tablet if the weight of the edge terminal 2 is equal to or greater than a predetermined threshold, and may determine that the edge terminal 2 is a smartphone if the weight of the edge terminal 2 is less than the predetermined threshold. When the control unit 6 determines that the edge terminal 2 is a tablet, the control unit 6 may control the drive unit 5 to increase the distance between the edge terminal 2 and the optical system 4. Alternatively, when the control unit 6 determines that the edge terminal 2 is a smartphone, the control unit 6 may control the drive unit 5 to decrease the distance between the edge terminal 2 and the optical system 4. Furthermore, when the control unit 6 determines that the edge terminal 2 is a tablet, the control unit 6 may control the drive unit 5 to decrease the distance between the edge terminal 2 and the optical system 4. Alternatively, when the control unit 6 determines that the edge terminal 2 is a smartphone, the control unit 6 may control the drive unit 5 to increase the distance between the edge terminal 2 and the optical system 4. In this case, regardless of the type of edge terminal 2, the size of the virtual image V in the field of view of the user 15 can be maintained approximately constant, thereby improving the comfort and convenience of the user 15. A tablet is an example of an edge terminal having a larger display surface 2a than a smartphone, and a smartphone may be an example of an edge terminal having a smaller display surface 2a than a tablet.

[0042] The terminal holding unit 3 may detect only the weight of the edge terminal 2 without determining the type of the edge terminal 2. The control unit 6 may control the drive unit 5 based on the detected weight of the edge terminal 2. The control unit 6 may control the drive unit 5 to change the distance between the edge terminal 2 and the optical system 4 based on the detected weight of the edge terminal 2. The control unit 6 may control the drive unit 5 so that the greater the detected weight of the edge terminal 2, the greater the distance between the edge terminal 2 and the optical system 4. Furthermore, the control unit 6 may control the drive unit 5 so that the greater the detected weight of the edge terminal 2, the smaller the distance between the edge terminal 2 and the optical system 4. Even in this case, the size of the virtual image V in the field of view of the user 15 can be maintained approximately constant, thereby improving the comfort and convenience of the user 15.

[0043] The device holding unit 3 is configured to detect the external dimensions of the edge terminal 2 inserted into the device holding unit 3 and may determine the type of the edge terminal 2 based on the detected external dimensions of the edge terminal 2. The external dimensions of the edge terminal 2 may be the area of ​​the edge terminal 2 when viewed from the depth direction of the edge terminal 2 inserted into the device holding unit 3, the width (X-axis) dimension, the height (Y-axis) dimension, the larger of the width and height dimensions, or the diagonal dimension, etc. If the external dimensions of the edge terminal 2 are equal to or greater than a predetermined threshold, the device holding unit 3 may determine that the edge terminal 2 is a tablet, and if the external dimensions of the edge terminal 2 are less than the predetermined threshold, the device holding unit 3 may determine that the edge terminal 2 is a smartphone. When the control unit 6 determines that the edge terminal 2 is a tablet, the control unit 6 may control the drive unit 5 to increase the distance between the edge terminal 2 and the optical system 4. Alternatively, when the control unit 6 determines that the edge terminal 2 is a smartphone, the control unit 6 may control the drive unit 5 to decrease the distance between the edge terminal 2 and the optical system 4. Furthermore, when the control unit 6 determines that the edge terminal 2 is a tablet, it may control the drive unit 5 to decrease the distance between the edge terminal 2 and the optical system 4. Alternatively, when the control unit 6 determines that the edge terminal 2 is a smartphone, it may control the drive unit 5 to increase the distance between the edge terminal 2 and the optical system 4. In this case, regardless of the type of edge terminal 2, the size of the virtual image V in the field of view of the user 15 can be maintained approximately constant, thereby improving the comfort and convenience of the user 15.

[0044] The terminal holding unit 3 may detect only the outer dimensions of the edge terminal 2 without determining the type of the edge terminal 2. The control unit 6 may control the drive unit 5 based on the detected outer dimensions of the edge terminal 2. The control unit 6 may control the drive unit 5 to change the distance between the edge terminal 2 and the optical system 4 based on the detected outer dimensions of the edge terminal 2. The control unit 6 may control the drive unit 5 so that the larger the outer dimensions of the detected edge terminal 2, the greater the distance between the edge terminal 2 and the optical system 4. Furthermore, the control unit 6 may control the drive unit 5 so that the larger the outer dimensions of the detected edge terminal 2, the smaller the distance between the edge terminal 2 and the optical system 4. Even in this case, the size of the virtual image V in the field of view of the user 15 can be maintained approximately constant, thereby improving the comfort and convenience of the user 15.

[0045] The terminal holding unit 3 may be configured to include, for example, a photodiode, an infrared sensor, or the like for detecting the external dimensions of the edge terminal 2. Alternatively, as shown in FIG. 6 , the terminal holding unit 3 may be configured to include at least one pin 31 in the groove of the left end holding unit 3 a and / or the right end holding unit 3 b and in the groove of the lower end holding unit 3 c. The at least one pin 31 may be biased toward the groove and configured to retract (be pushed in) when the edge terminal 2 abuts against it. The terminal holding unit 3 may be configured to detect the number, position, amount of retraction (length of retraction), etc. of the pins 31 pushed in when the edge terminal 2 abuts against it. The terminal holding unit 3 may detect the external dimensions of the edge terminal 2 based on the number, position, etc. of the pins 31 pushed in when the edge terminal 2 abuts against it. The terminal holding unit 3 may detect the weight of the edge terminal 2 based on the number and / or amount of retraction of the pins 31 pushed in when the edge terminal 2 abuts against it.

[0046] The control unit 6 may determine the size of the display surface 2a of the edge terminal 2 based on the external dimensions of the edge terminal 2. The control unit 6 may determine the center C of the display surface 2a based on the external dimensions of the edge terminal 2. The control unit 6 may take into account the bezel (frame) width of the edge terminal 2 when determining the center C of the display surface 2a and the size of the display surface 2a.

[0047] The control unit 6 may control the drive unit 5 so as to position the center C of the display surface 2 a of the edge terminal 2 on the optical axis of the optical system 4. In this case, the position (projection position) of the virtual image V within the field of view of the user 15 can be maintained approximately constant, thereby improving the comfort and convenience of the user 15.

[0048] The display device 1 may include a touch panel 14. The touch panel 14 is disposed in the optical path of the image light that has passed through the optical system 4, and may transmit a portion of the image light that has passed through the optical system 4. The touch panel 14 does not have to be disposed in the optical path of the image light that has passed through the optical system 4. The touch panel 14 may be a known touch panel.

[0049] The touch panel 14 may be communicatively connected to the edge terminal 2 via a wired or wireless communication line. The touch panel 14 and the edge terminal 2 may be communicatively connected by a communication cable. The communication cable may be, for example, a USB (Universal Serial Bus) standard communication cable (USB cable). A first end of the communication cable may be inserted into an input / output port (USB port) of the touch panel 14, and a second end of the communication cable may be inserted into an input / output port (USB port) of the edge terminal 2. The touch panel 14 and the edge terminal 2 may be communicatively connected by a communication method such as Bluetooth (registered trademark).

[0050] The edge terminal 2 may be pre-installed with software for operating the touch panel 14. The software may have a function to display a notification icon on the display surface 2a when the edge terminal 2 is inserted into the terminal holding unit 3 and communication with the touch panel 14 is established, notifying the user 15 that preparations for calibrating the position of the edge terminal 2 are complete. The software may have a function to cause the control unit 6 to calibrate the position of the edge terminal 2 when the user 15 touches an area on the touch panel 14 that corresponds to the notification icon.

[0051] 2 , the display device 1 may include a housing 13 that houses an edge terminal 2, a terminal holding unit 3, an optical system 4, a drive unit 5, and a control unit 6, and has an opening 13a through which image light that has passed through the optical system 4 passes. The touch panel 14 may be arranged to cover part or all of the opening 13a. The touch panel 14 only needs to be communicably connected to the edge terminal 2, and therefore the touch panel 14 may or may not be attached to the housing 13.

[0052] Power for operating the display device 1 may be supplied from a power source such as an on-board battery mounted on the vehicle 16. The display device 1 may be capable of charging the edge terminal 2. In this case, convenience for the user 15 can be improved. The display device 1 may be capable of contactless charging (also called wireless charging) the edge terminal 2. The display device 1 may be capable of operating while charging the edge terminal 2.

[0053] The display device 1 may include an external speaker 17 communicatively connected to the edge terminal 2. The external speaker 17 may be configured to receive an audio signal output from the edge terminal 2 and transmit audio to the user 15. The external speaker 17 may be communicatively connected to the edge terminal 2 via a wired or wireless communication line. The external speaker 17 may be attached to the housing 13.

[0054] The display device 1 may include a built-in battery. The display device 1 may operate using power supplied from the built-in battery. In this case, the display device 1 can be removed from the front seat of the vehicle 16 and used.

[0055] The display device 1 may include a camera that captures an image of the user 15. The camera may include, for example, a CCD (charge-coupled device) or a CMOS (complementary metal-oxide semiconductor) image sensor. The camera may be communicatively connected to the edge terminal 2 via a wired or wireless communication line. The display device 1 may include a microphone that detects the voice of the user 15. The microphone may be communicatively connected to the edge terminal 2 via a wired or wireless communication line.

[0056] The control unit 6 may control the drive unit 5 so that the focal length of the second semi-transparent mirror 8 and the focal length of the third semi-transparent mirror 9 are approximately equal. Furthermore, the control unit 6 may control the drive unit 5 so that the distance between the first semi-transparent mirror 7 and the second semi-transparent mirror 8 is approximately equal to the distance between the first semi-transparent mirror 7 and the third semi-transparent mirror 9, and the optical path length between the edge terminal 2 and the second semi-transparent mirror 8 or the third semi-transparent mirror 9 is longer than the focal lengths of the second semi-transparent mirror 8 and the third semi-transparent mirror 9. This optical path length is the distance between the edge terminal 2 and the third semi-transparent mirror 9, and the focal lengths of the second semi-transparent mirror 8 and the third semi-transparent mirror 9 may be the focal lengths on the edge terminal 2 side of the optical system 4. In this case, the virtual image formed by the image light traveling along path P1 and the virtual image formed by the image light traveling along path P2 are equal to each other, thereby improving the display quality of the virtual image V viewed by the user 15. The driving unit 5 may set the ratio of the focal length of the third semi-transparent mirror 9 to the focal length of the second semi-transparent mirror 8 to be 0.9 to 1.1, or 0.95 to 1.05. The driving unit 5 may set the ratio of the distance between the first semi-transparent mirror 7 and the third semi-transparent mirror 9 to the distance between the first semi-transparent mirror 7 and the second semi-transparent mirror 8 to be 0.9 to 1.1, or 0.95 to 1.05.

[0057] A display device according to a second embodiment of the present disclosure will be described below.

[0058] 7 is a schematic diagram illustrating an example of an optical system of a display device according to the second embodiment. The display device 1A of this embodiment differs from the display device 1 of the first embodiment in the configuration of the optical system, but is otherwise similar to the display device 1. Therefore, the same components as those of the display device 1 are denoted by the same reference numerals as those of the display device 1, and detailed descriptions thereof will be omitted.

[0059] As shown in FIG. 2 , the display device 1A may include an edge terminal 2, a terminal holding unit 3, an optical system 19, a drive unit 5, and a control unit 6.

[0060] 7 , the optical system 19 may include a first semi-transparent mirror 20, a first retardation plate 21, a second semi-transparent mirror 22, a second retardation plate 23, and a polarizing plate 24. The first semi-transparent mirror 20, the first retardation plate 21, the second semi-transparent mirror 22, the second retardation plate 23, and the polarizing plate 24 may be arranged in this order in the emission direction (Z-axis direction) of the image light from the edge terminal 2.

[0061] The first retardation plate 21 may be positioned opposite the reflecting surface 20a of the first semi-transparent mirror 20. The first retardation plate 21 may be positioned away from the display surface 2a of the edge terminal 2 in the emission direction (Z-axis direction) of the image light. The second retardation plate 23 may be positioned away from the first retardation plate 21 in the emission direction (Z-axis direction) of the image light. The first retardation plate 21 and the second retardation plate 23 may be quarter-wave plates.

[0062] The first semi-transmitting mirror 20 may be located between the edge terminal 2 and the first retardation plate 21. The first semi-transmitting mirror 20 may transmit a portion of the incident light and reflect the remainder. As shown in FIG. 7 , the first semi-transmitting mirror 20 may be a concave mirror having a concave reflective surface 20a facing the first retardation plate 21. The first semi-transmitting mirror 20 may be configured to transmit S-wave polarized light and reflect P-wave polarized light. At least a portion of the reflective surface 20a of the first semi-transmitting mirror 20 may include a spherical shape, an aspherical shape, or a free-form surface shape.

[0063] The first semi-transparent mirror 20 may be configured to include, for example, a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be configured from, for example, a resin material, a glass material, or the like. The resin material may be, for example, an acrylic resin, a polycarbonate resin, or the like. The thin metal wires may be configured from a metal material such as aluminum, chromium, or titanium oxide. The thin metal wires may be arranged in one direction. The first semi-transparent mirror 20 can transmit light components vibrating in a direction perpendicular to the grid and reflect light components vibrating in a direction parallel to the grid.

[0064] The second semi-transmitting mirror 22 is located between the first retardation plate 21 and the second retardation plate 23. The second semi-transmitting mirror 22 may transmit a portion (approximately 50%) of the incident light and reflect the remaining portion (approximately 50%). As shown in FIG. 7 , the second semi-transmitting mirror 22 may be a plane mirror positioned so that its reflective surface 22 a faces the first retardation plate 21. The second semi-transmitting mirror 22 is also called a plane half mirror.

[0065] The second semi-transparent mirror 22 may be configured to include, for example, a substrate and a semi-transparent layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be configured from, for example, inorganic glass, a resin material, or the like. The resin material may be, for example, an acrylic resin, a polycarbonate resin, or the like. The semi-transparent layer may be a metal thin film. The metal thin film may be configured from a metal material such as aluminum, chromium, or the like. The semi-transparent layer is not limited to a metal thin film and may be, for example, a dielectric multilayer film, or the like.

[0066] The polarizing plate 24 may be positioned opposite to the surface of the second retardation plate 23 that faces the second semi-transparent mirror 22. In other words, the polarizing plate 24 may be positioned after the second retardation plate 23 in the emission direction of the image light from the edge terminal 2.

[0067] The polarizing plate 24 may transmit a portion of the incident light and absorb the remainder. The polarizing plate 24 may transmit P-wave polarized light and absorb S-wave polarized light. The polarizing plate 24 may have the configuration of a known absorptive polarizing plate. Examples of known absorptive polarizing plates include an iodine-based polarizing plate in which an iodine compound is adsorbed and aligned on a polyvinyl alcohol (PVA) film, and a dye-based polarizing plate in which a dichroic organic dye is adsorbed and aligned on a PVA film.

[0068] The polarizing plate 24 may transmit a portion of the incident light and reflect the remainder. The polarizing plate 24 may transmit P-polarized light and reflect S-polarized light. The polarizing plate 24 may be configured, for example, to include a substrate and a plurality of thin metal wires (metal nanowire grid) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light range. The substrate may be configured, for example, of a resin material, a glass material, or the like. The resin material may be, for example, an acrylic resin, a polycarbonate resin, or the like. The thin metal wires may be configured, for example, of a metal material such as aluminum, chromium, or titanium oxide. The polarizing plate 24 can transmit polarized light vibrating in a direction perpendicular to the grid and can reflect polarized light vibrating in a direction parallel to the grid.

[0069] The optical function of the optical system 19 will be described. Image light of the first linearly polarized light L1 emitted from the edge terminal 2 passes through the first semi-transparent mirror 20. The image light of the first linearly polarized light L1 passes through the first retardation plate 21 and is converted into light of the first circularly polarized light C1. The light of the first circularly polarized light C1 is incident on the second semi-transparent mirror 22. A portion (approximately 50%) of the light of the first circularly polarized light C1 is reflected by the second semi-transparent mirror 22 and converted into light of the second circularly polarized light C2. The light of the second circularly polarized light C2 passes through the first retardation plate 21 and is converted into light of the second linearly polarized light L2, whose polarization axis is orthogonal to the polarization axis of the first linearly polarized light L1. The light of the second linearly polarized light L2 is reflected by the first semi-transparent mirror 20 and is converted into light of the third linearly polarized light L3, whose polarization axis is orthogonal to the polarization axis of the first linearly polarized light L1. The light of the third linearly polarized light L3 passes through the first retardation plate 21 and is converted into light of the third circularly polarized light C3. A portion (approximately 50%) of the light of the third circularly polarized light C3 is transmitted through the second semi-transparent mirror 22. The light of the third circularly polarized light C3 that has transmitted through the second semi-transparent mirror 22 is transmitted through the second retardation plate 23 and converted into light of the fourth linearly polarized light L4 whose polarization axis is perpendicular to the polarization axis of the first linearly polarized light L1. The light of the fourth linearly polarized light L4 is transmitted through the polarizing plate 24 and emitted to the outside.

[0070] The remaining portion (approximately 50%) of the light of the first circularly polarized light C1 passes through the second semi-transparent mirror 22, then passes through the second retardation plate 23, and is converted into light of fifth linearly polarized light L5, the polarization axis of which is parallel to the polarization axis of the first linearly polarized light L1. The light of the fifth linearly polarized light L5 is absorbed or reflected by the polarizing plate 24, and is therefore not emitted to the outside. The amount of light emitted from the display device 1A is approximately 25% of the amount of light emitted from the edge terminal 2.

[0071] In one embodiment of the present disclosure, the first linearly polarized light L1 and the fifth linearly polarized light L5 may be S-wave polarized light, and the second linearly polarized light L2 to the fourth linearly polarized light L4 may be P-wave polarized light.

[0072] In the above description, the first semi-transparent mirror 20 has polarization selectivity, but this is not limiting. The first semi-transparent mirror 20 does not have to have polarization selectivity. The first semi-transparent mirror 20 is a half mirror composed of a base material and a semi-transparent layer (a semi-transparent layer that does not have polarization selectivity) located on the surface of the base material, and may transmit a portion (approximately 50%) of incident light and reflect the remaining portion (approximately 50%).

[0073] The first semi-transmitting mirror 20 is not limited to a concave mirror. The first semi-transmitting mirror 20 may be configured as a holographic optical element. In this case, the optical function of the first semi-transmitting mirror 20 can be realized by a flat optical member. As a result, the thickness of the first semi-transmitting mirror 20 in the depth direction (Z-axis direction) can be reduced, making it possible to miniaturize the optical system 19 in the depth direction. This in turn makes it possible to miniaturize the display device 1A in the depth direction.

[0074] Since the optical system 19 is a uniaxial (on-axis) optical system in which the optical axis of the incident light and the optical axis of the outgoing light are substantially aligned, the space occupied by the optical system 19 can be reduced, thereby enabling the display device 1A to be miniaturized. Furthermore, since the optical system 19 is a uniaxial type, distortion and brightness unevenness of the virtual image V viewed by the user 15 can be reduced, and the design of the optical system 19 becomes easier.

[0075] The driving unit 5 may adjust the relative position between the focal point (object focal point) F on the edge terminal 2 side of the optical system 19 and the edge terminal 2. The driving unit 5 may be configured to be able to adjust the distance between the optical system 19 and the terminal holding unit 3 that holds the edge terminal 2. The driving unit 5 may be configured to be able to adjust the relative positions of the optical members included in the optical system 19, in particular the relative positions of the first semi-transparent mirror 20 and the second semi-transparent mirror 22.

[0076] The driver 5 may be configured to be able to adjust the focal length of the first semi-transparent mirror 20. The driver 5 may change the focal length of the first semi-transparent mirror 20, for example, by deforming the first semi-transparent mirror 20. The driver 5 may change the focal length of the first semi-transparent mirror 20, for example, by changing the curvature, shape, etc. of the reflecting surface 20 a.

[0077] The control unit 6 may control the drive unit 5 so that the edge terminal 2 is located closer to the object focus F in the optical system 19. In other words, the control unit 6 may control the drive unit 5 so that the optical path length of the image light from the edge terminal 2 to the second semi-transparent mirror 22 via the first semi-transparent mirror 20 is shorter than the focal length of the first semi-transparent mirror 20. This allows the display device 1A to project the image displayed on the edge terminal 2 as a virtual image V within the field of view of the user 15, thereby improving the convenience of the user 15. Furthermore, the display device 1A can project the image displayed on the edge terminal 2 as a virtual image V located further back than the display device 1A within the field of view of the user 15. This reduces the risk that the user 15 will feel a sense of oppression, thereby improving the comfort and convenience of the user 15.

[0078] When the display device 1 is attached to the back of the front seat of the vehicle 16 and allows the user 15 seated in the rear seat to view the virtual image V, the control unit 6 may control the size of the display area of ​​the image displayed on the drive unit 5 or the edge terminal 2 so as to change the size or position of the virtual image V as the front seat or the rear seat moves forward or backward. For example, the control unit 6 may control the size of the display area of ​​the image displayed on the drive unit 5 or the edge terminal 2 so as to increase the size of the virtual image V when the front seat moves forward or the rear seat moves backward. The control unit 6 may control the size of the display area of ​​the image displayed on the drive unit 5 or the edge terminal 2 so as to decrease the size of the virtual image V when the front seat moves backward or the rear seat moves forward. In this case, it is possible to reduce the change in the size of the virtual image V in the field of view of the user 15 as the front seat or the rear seat moves forward or backward. Furthermore, for example, the control unit 6 may control the drive unit 5 so that the position of the virtual image V moves toward the user 15 (also referred to as the rearward direction) when the front seat moves forward or the rear seat moves backward. The control unit 6 may control the drive unit 5 so that the position of the virtual image V moves in a direction away from the user 15 (also referred to as the forward direction) when the front seat moves backward or the rear seat moves forward. In this case, it is possible to reduce changes in the distance from the user 15 to the virtual image V that accompany the forward or backward movement of the front seat or the rear seat. In the vehicle 16, by using a sensor (such as a potentiometer, a linear encoder, a magnetic sensor, or a non-contact sensor), a signal indicating the position of the front seat or the rear seat may be transmitted to the display device 1 as the front seat or the rear seat moves.

[0079] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be variously changed, modified, or modified within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. For example, the functions contained in each component, etc. can be rearranged so as not to cause logical contradictions, and multiple components, etc. can be combined into one or divided. In other words, it should be noted that those skilled in the art can easily make various modifications or alterations based on the present disclosure. It should also be noted that these modifications, alterations, or alterations are included within the scope of the present disclosure.

[0080] The display device of the present disclosure can be implemented in the following aspects (1) to (12).

[0081] (1) A display device comprising: a terminal holding unit that detachably holds an edge terminal; and an optical system that forms image light emitted from the edge terminal as a virtual image within a user's field of view.

[0082] (2) The display device described in (1) above, comprising: a drive unit that adjusts the relative position between the focal point on the edge terminal side of the optical system and the edge terminal; and a control unit, wherein the control unit controls the drive unit so that the edge terminal is positioned closer to the focal point on the edge terminal side of the optical system.

[0083] (3) The display device according to (2) above, wherein the terminal holding unit is configured to be able to detect specifications of the edge terminal, and the control unit controls the drive unit based on the detected specifications of the edge terminal.

[0084] (4) The display device described in (3) above, wherein the control unit controls the drive unit to change the distance between the edge terminal and the optical system based on the detected specifications of the edge terminal.

[0085] (5) The display device according to any one of (1) to (4) above, comprising a touch panel that transmits a portion of the image light that has passed through the optical system.

[0086] (6) The optical system includes: a first semi-transparent mirror located at a distance from the edge terminal in the emission direction of the image light; a first retardation plate located between the edge terminal and the first semi-transparent mirror; a second retardation plate located on the opposite side of the first semi-transparent mirror to the first retardation plate; a second semi-transparent mirror located between the edge terminal and the first retardation plate and having a concave reflecting surface facing the first retardation plate, the second semi-transparent mirror transmitting polarized light having a polarization axis in a first direction and reflecting polarized light having a polarization axis in a second direction orthogonal to the first direction; and a third semi-transparent mirror located on the opposite side of the second semi-transparent mirror across the first semi-transparent mirror, the first retardation plate, and the second retardation plate, having a concave reflecting surface facing the second retardation plate, the third semi-transparent mirror reflecting polarized light having a polarization axis in the first direction and transmitting polarized light having a polarization axis in the second direction, The display device according to any one of (1) to (5) above, configured so that linearly polarized image light having a polarization axis in the first direction is incident on the optical system.

[0087] (7) The display device described in (6) above, wherein the control unit controls the drive unit so that the distance between the first semi-transparent mirror and the second semi-transparent mirror is approximately the same as the distance between the first semi-transparent mirror and the third semi-transparent mirror, and the distance between the edge terminal and the third semi-transparent mirror is smaller than the focal length on the edge terminal side in the optical system.

[0088] (8) The optical system includes: a first semi-transparent mirror positioned at a distance from the edge terminal in the emission direction of the image light; a first retardation plate positioned between the edge terminal and the first semi-transparent mirror; a second retardation plate positioned on the opposite side of the first semi-transparent mirror from the first retardation plate; a second semi-transparent mirror positioned between the edge terminal and the first retardation plate and having a concave reflecting surface facing the first retardation plate; a third semi-transparent mirror positioned on the opposite side of the second semi-transparent mirror from the first semi-transparent mirror, the first retardation plate, and the second retardation plate and having a concave reflecting surface facing the second retardation plate; and a polarizing plate positioned at a distance from the second retardation plate in the emission direction, the polarizing plate reflecting polarized light having a polarization axis in a first direction and transmitting polarized light having a polarization axis in a second direction orthogonal to the first direction, wherein the first retardation plate and the second retardation plate are quarter-wave plates, The display device according to any one of (1) to (5) above, configured so that linearly polarized image light having a polarization axis in the first direction is incident on the optical system.

[0089] (9) The display device described in (8) above, wherein the control unit controls the drive unit so that the distance between the first semi-transparent mirror and the second semi-transparent mirror is approximately the same as the distance between the first semi-transparent mirror and the third semi-transparent mirror, and the distance between the edge terminal and the third semi-transparent mirror is smaller than the focal length on the edge terminal side in the optical system.

[0090] (10) The display device according to any one of (1) to (5), wherein the optical system includes: a first retardation plate positioned at a distance from the edge terminal in the emission direction of the image light; a second retardation plate positioned at a distance from the first retardation plate in the emission direction; a first semi-transparent mirror positioned between the edge terminal and the first retardation plate and having a concave reflective surface facing the first retardation plate; a second semi-transparent mirror positioned between the first retardation plate and the second retardation plate; and a polarizer positioned at a distance from the second retardation plate in the emission direction, the polarizer reflecting or absorbing polarized light having a polarization axis in a first direction and transmitting polarized light having a polarization axis in a second direction orthogonal to the first direction, wherein the first retardation plate and the second retardation plate are quarter-wave plates; and the display device is configured such that linearly polarized image light having a polarization axis in the first direction is incident on the optical system.

[0091] (11) The display device described in (10) above, wherein the first semi-transparent mirror transmits polarized light having a polarization axis in the first direction and reflects polarized light having a polarization axis in a second direction perpendicular to the first direction.

[0092] (12) The display device described in (10) or (11) above, wherein the control unit controls the drive unit so that the sum of twice the distance between the first semi-transparent mirror and the second semi-transparent mirror and the distance between the edge terminal and the first semi-transparent mirror is smaller than the focal length on the edge terminal side in the optical system.

[0093] REFERENCE SIGNS LIST 1, 1A Display device 2 Edge terminal 2a Display surface 3 Terminal holding section 3a Left edge holding section 3b Right edge holding section 3c Bottom edge holding section 31 Pin 4 Optical system 5 Drive section 6 Control section 7 First semi-transparent mirror 7a Reflecting surface 7b Reflecting surface 8 Second semi-transparent mirror 8a Reflecting surface 9 Third semi-transparent mirror 9a Reflecting surface 10 First retardation plate 11 Second retardation plate 13 Housing 13a Opening 14 Touch panel 15 User 16 Vehicle 17 External speaker 18 Polarizer 19 Optical system 20 First semi-transparent mirror 20a Reflecting surface 21 First retardation plate 22 Second semi-transparent mirror 22a Reflecting surface 23 Second retardation plate 24 Polarizer

Claims

1. A display device comprising: a terminal holding unit that detachably holds an edge terminal; and an optical system that forms image light emitted from the edge terminal as a virtual image within the user's field of view.

2. A display device as described in claim 1, comprising: a drive unit that adjusts the relative position between the focal point on the edge terminal side of the optical system and the edge terminal; and a control unit, wherein the control unit controls the drive unit so that the edge terminal is positioned closer to the focal point on the edge terminal side of the optical system.

3. The display device according to claim 2, wherein the terminal holding unit is configured to be able to detect the specifications of the edge terminal, and the control unit controls the drive unit based on the detected specifications of the edge terminal.

4. The display device according to claim 3, wherein the control unit controls the drive unit to change the distance between the edge terminal and the optical system based on the detected specifications of the edge terminal.

5. The display device according to any one of claims 1 to 4, comprising a touch panel that transmits a portion of the image light that has passed through the optical system.

6. The optical system includes: a first semi-transparent mirror located at a distance from the edge terminal in the emission direction of the image light; a first retardation plate located between the edge terminal and the first semi-transparent mirror; a second retardation plate located on the opposite side of the first semi-transparent mirror from the first retardation plate; a second semi-transparent mirror located between the edge terminal and the first retardation plate and having a concave reflecting surface facing the first retardation plate, the second semi-transparent mirror transmitting polarized light having a polarization axis in a first direction and reflecting polarized light having a polarization axis in a second direction perpendicular to the first direction; and a third semi-transparent mirror located on the opposite side of the second semi-transparent mirror between the first semi-transparent mirror, the first retardation plate, and the second retardation plate, having a concave reflecting surface facing the second retardation plate, the third semi-transparent mirror reflecting polarized light having a polarization axis in the first direction and transmitting polarized light having a polarization axis in the second direction, The display device according to claim 1 , wherein the optical system is configured so that linearly polarized image light having a polarization axis in the first direction is incident on the optical system.

7. A display device as described in claim 6, comprising: a drive unit that adjusts the relative position between the focal point on the edge terminal side in the optical system and the edge terminal; and a control unit, wherein the control unit controls the drive unit so that the distance between the first semi-transparent mirror and the second semi-transparent mirror and the distance between the first semi-transparent mirror and the third semi-transparent mirror are approximately the same, and the distance between the edge terminal and the third semi-transparent mirror is smaller than the focal length on the edge terminal side in the optical system.

8. The optical system comprises: a first semi-transparent mirror located at a distance from the edge terminal in the emission direction of the image light; a first retardation plate located between the edge terminal and the first semi-transparent mirror; a second retardation plate located on the opposite side of the first semi-transparent mirror from the first retardation plate; a second semi-transparent mirror located between the edge terminal and the first retardation plate and having a concave reflecting surface facing the first retardation plate; a third semi-transparent mirror located on the opposite side of the second semi-transparent mirror from the first semi-transparent mirror, the first retardation plate, and the second retardation plate and having a concave reflecting surface facing the second retardation plate; and a polarizing plate located at a distance from the second retardation plate in the emission direction, which reflects polarized light having a polarization axis in a first direction and transmits polarized light having a polarization axis in a second direction perpendicular to the first direction, wherein the first retardation plate and the second retardation plate are quarter-wave plates, The display device according to claim 1 , wherein the optical system is configured so that linearly polarized image light having a polarization axis in the first direction is incident on the optical system.

9. A display device as described in claim 8, comprising: a drive unit that adjusts the relative position between the focal point on the edge terminal side in the optical system and the edge terminal; and a control unit, wherein the control unit controls the drive unit so that the distance between the first semi-transparent mirror and the second semi-transparent mirror and the distance between the first semi-transparent mirror and the third semi-transparent mirror are approximately the same, and the distance between the edge terminal and the third semi-transparent mirror is smaller than the focal length on the edge terminal side in the optical system.

10. A display device according to any one of claims 1 to 5, wherein the optical system comprises: a first retardation plate positioned at a distance from the edge terminal in the emission direction of the image light; a second retardation plate positioned at a distance from the first retardation plate in the emission direction; a first semi-transparent mirror positioned between the edge terminal and the first retardation plate and having a concave reflective surface facing the first retardation plate; a second semi-transparent mirror positioned between the first retardation plate and the second retardation plate; and a polarizer positioned at a distance from the second retardation plate in the emission direction, the polarizer reflecting or absorbing polarized light having a polarization axis in a first direction and transmitting polarized light having a polarization axis in a second direction perpendicular to the first direction, wherein the first retardation plate and the second retardation plate are quarter-wave plates; and the display device is configured so that linearly polarized image light having a polarization axis in the first direction is incident on the optical system.

11. The display device according to claim 10, wherein the first semi-transparent mirror transmits polarized light having a polarization axis in the first direction and reflects polarized light having a polarization axis in a second direction perpendicular to the first direction.

12. A display device as described in claim 10 or 11, comprising: a drive unit that adjusts the relative position between the focal point on the edge terminal side in the optical system and the edge terminal; and a control unit, wherein the control unit controls the drive unit so that the sum of twice the distance between the first semi-transparent mirror and the second semi-transparent mirror and the distance between the edge terminal and the first semi-transparent mirror is smaller than the focal length on the edge terminal side in the optical system.

Images