Image display device and image display system

Abstract

According to the present invention, an image display device and an image display system of a light guide plate type capable of displaying images with less chromatic aberration and image distortion are provided. In the image display device (101) for displaying images, an image projection unit (200) for projecting image light, an image deflection unit (210) and a light guide unit (230) are provided. The image deflection unit (210) deflects the image light emitted by the image projection unit (200) and propagates it to the light guide unit (230). The light guide unit (230) propagates the incident image light inside and outputs it. Here, the image deflection unit (210) or the light guide unit (230) has a structure for reducing the dispersion of the image light output from the light guide unit (230).

Description

Technical Field

[0001] The invention relates to an image display device and an image display system. Background Art

[0002] Image display devices and image display systems such as head mounted displays that present images generated by an image generating device to a user are known. Patent document 1 discloses a light guide plate having a plurality of beam splitting surfaces therein as a light guide plate that transmits generated image light to the eyes of the user. In addition, the document discloses an image display system that uses a coupling prism to couple the image light generated by the image generating device with the light guide plate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent Application Publication No. 2010 / 0067110 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the image display system described in Patent Document 1, the image light generated by the image generating device is reflected by the coupling prism and taken in by the light guide plate. However, no special consideration is given to the dispersion caused by the refraction when the image light is incident on the coupling prism and the light guide plate, and the image visually recognized by the user may have chromatic aberration and image distortion.

[0008] In view of the above problems, an object of the present invention is to provide a light guide plate type image display device and an image display system capable of displaying images with less color difference and image distortion to users.

[0009] Means for solving problems

[0010] The image display device of the present invention includes an image projection unit for projecting image light, an image deflection unit and a light guiding unit. The image deflection unit deflects the image light emitted by the image projection unit and propagates it to the light guiding unit. The light guiding unit propagates the incident image light inside it and outputs it. The image deflection unit or the light guiding unit includes a structure for reducing the dispersion of the image light output from the light guiding unit.

[0011] Furthermore, an image display system of the present invention includes: the image display device described above; and an image signal processing unit that generates a projection image signal for the image projection unit to project image light.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to provide a light guide plate type image display device and an image display system capable of displaying images with less color difference and image distortion. Other problems, structures and effects than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram showing the functional block structure of the image display system 100 according to the first embodiment.

[0015] Figure 2 1 is a diagram showing the appearance of the video display system 100 .

[0016] Figure 3 This is a diagram showing the functional block structure of the video display device 101.

[0017] Figure 4 It is a schematic diagram showing the operation of the light guide plate 220 .

[0018] Figure 5 1 is a diagram showing a configuration example of the image deflection unit 210 and the light guide unit 230 .

[0019] Figure 6 2 is a diagram showing an example of propagation of image light emitted from the image projection unit 200 .

[0020] Figure 7 It is a diagram showing a configuration in which the arrangement of the image projection unit 200 is changed.

[0021] Figure 8 It is a diagram showing other structures of the light guide plate and the deflection prism.

[0022] Fig. 9 It is a diagram showing other structures of the light guide plate and the deflection prism.

[0023] Fig.10 It is a diagram showing other structures of the light guide plate and the deflection prism.

[0024] Fig.11 It is a diagram showing other structures of the light guide plate and the deflection prism.

[0025] Fig.12 It is a diagram showing other structures of the light guide plate and the deflection prism.

[0026] Fig.13 1 is a diagram showing the structure of the image deflection unit 210 and the light guide unit 230 according to the second embodiment.

[0027] Fig.14 2 is a diagram showing other structures of the image deflection unit 210 and the light guide unit 230 .

[0028] Fig.152 is a diagram showing other structures of the image deflection unit 210 and the light guide unit 230 .

[0029] Fig.16 1 is a diagram showing the structure of the image deflection unit 210 and the light guide unit 230 according to the third embodiment.

[0030] Fig.17 This is a diagram showing the structure of the image display device 101 of the fourth embodiment.

[0031] Fig.18 This is a diagram showing the structure of the image display device 101 of Example 5.

[0032] Fig.19 1 is a diagram showing a configuration in which the image signal processing unit 104 performs image correction. DETAILED DESCRIPTION

[0033] Below, use accompanying drawing to describe the embodiment of the present invention in detail.In addition, the following description is used to illustrate an embodiment of the present invention, and does not limit the scope of the present invention.Therefore, those skilled in the art can adopt the embodiment that these each element or all elements are replaced with the element equivalent thereto, and these embodiments are also included in the scope of the present invention.

[0034] Example 1

[0035] Figure 1 1 is a diagram showing the structure of the functional blocks of the image display system 100 of the first embodiment. The image display system 100 is a system having a function of displaying images, such as a head mounted display or a head-up display. The image display system 100 includes an image display device 101, a controller 102, an image signal processing unit 104, a power supply unit 105, a storage medium 106, a sensing unit 107, a sensor input / output unit 108, a communication unit 109, a communication input / output unit 110, a sound processing unit 111, and a sound input / output unit 112.

[0036] The image display device 101 is a device that generates an image and displays the image to a user of the image display system 100 , and the details will be described later.

[0037] The controller 102 controls the entire image display system 100. A central processing unit such as a CPU (Central Processing Unit) realizes the functions of the controller 102. The image signal processing unit 104 generates an image signal for an image displayed by the image display system 100. The power supply unit 105 is a power supply device or a battery that supplies power to the image display system 100.

[0038] The storage medium 106 stores information required for processing by the processing unit of the image display system 100 and the image display device 101 and information generated. The storage medium 106 is a storage device such as RAM (Random Access Memory) or flash memory, and functions as a storage area for temporarily reading programs and data. The storage medium 106 may also include a storage medium that can be written and read, such as HDD (Hard Disk Drive), CD-R (Compact Disc-Recordable), DVD-RAM (Digital Versatile Disk-Random Access Memory), and SSD (solid state drive), and a storage medium drive device. The controller 102 performs processing by a CPU that operates according to the program read from the storage medium 106. In addition, part or all of the processing may also be performed by other computing devices, such as hardware such as FPGA (Field Programmable Gate Array) and ASIC (Application Specific Integrated Circuit).

[0039] The sensing unit 107 detects the surrounding conditions using sensors. The sensing unit 107 detects the conditions using signals input to the sensor input / output unit 108 from sensors such as an illumination sensor for detecting the brightness of the surroundings, a tilt sensor for detecting the user's posture, orientation, movement, etc., an acceleration sensor, a line of sight sensor for detecting the user's physical condition, a temperature sensor, a GNSS (Global Navigation Satellite System) sensor for detecting the user's location information, a pressure-sensitive sensor, an electrostatic capacitance sensor, and a barcode reader.

[0040] The communication unit 109 is connected to a network (not shown) via a communication input / output unit 110. The communication unit 109 communicates with an information processing terminal (not shown) through short-range or long-range wireless communication or wired communication such as Bluetooth (registered trademark), Wi-Fi (registered trademark), UHF (Ultra High Frequency), or VHF (Very High Frequency). The sound processing unit 111 receives sound input or outputs sound using a sound input / output unit 112 such as a microphone or earphone.

[0041] In addition, the image display system 100 of this embodiment only needs to have the function of displaying images, and the sensing unit 107, the sensor input and output unit 108, the communication unit 109, the communication input and output unit 110, the sound processing unit 111, and the sound input and output unit 112 can be omitted.

[0042] Figure 2 1 is a diagram showing the appearance of the video display system 100 . Figure 2 The image display system 100 shown is a case of a head mounted display (also referred to as smart glasses) that can be used by a user 700 by wearing it on his or her head.

[0043] Figure 3 1 is a diagram showing the functional block structure of the video display device 101, and two structures (a) and (b) are described.

[0044] Figure 3 The image display device 101 of (a) includes an image projection unit 200, an image deflection unit 210, and a light guide unit 230. The image projection unit 200 includes an image generating device (not shown) that generates and outputs image light that becomes an image displayed by the image display device 101. The image light emitted from the image projection unit 200 is incident on the image deflection unit 210. The image deflection unit 210 deflects the image light output from the image projection unit 200 and propagates it to the light guide unit 230. In other words, the image light incident on the image deflection unit 210 is deflected by the image deflection unit 210, emitted from the image deflection unit 210, and incident on the light guide unit 230. The light guide unit 230 propagates the incident image light inside by total reflection of the inner surface, and outputs it to the outside. As the light guide unit 230, a light guide plate is used as follows.

[0045] In addition, if Figure 3 Like the image display device 101 of (b), the image light emitted from the image projection unit 200 may be once incident on the light guide unit 230 , propagates in the light guide unit 230 , and is emitted from the light guide unit 230 , and is incident on the image deflection unit 210 .

[0046] Figure 4 2 is a schematic diagram showing the operation of the light guide plate 220. Here, the XYZ axes are defined for the purpose of explaining the directions. The X axis is the long side direction of the light guide plate 220 (the propagation direction of the image light), the Y axis is the short side direction of the light guide plate 220, and the Z axis is the incident / emission direction of the image light.

[0047] The light guide plate 220 has a light input portion 221 and a light output portion 222. The image light emitted from the image deflection unit 210 is incident from the light input portion 221 of the light guide plate 220 into the interior of the light guide plate 220, and is propagated in the interior of the light guide plate 220 (in the X direction) by total reflection at the inner surface reflection surfaces 223 and 224 of the light guide plate 220. The image light propagated in the interior of the light guide plate 220 is output from the light output portion 222 (in the Z direction). A portion of the image light output from the light output portion 222 of the light guide plate 220 is incident on the user's eye 120. The user can visually confirm the image displayed by the image display device 101 by sensing the light incident on the eye 120.

[0048] Figure 5 8 is a diagram showing a configuration example of the image deflection unit 210 and the light guide unit 230 . The light guide unit 230 includes a light guide plate 801 , and the image deflection unit 210 includes a deflection prism 301 . Figure 5 (a) is the front view (viewed from the Z direction), Figure 5 (b) is a top view (viewed from the Y direction), Figure 5 (c) is a side view (viewed from the X direction).

[0049] The light guide plate 801 is composed of a hexahedron, and has an end face 11, a terminal face 12, a first inner surface reflection surface 13, a second inner surface reflection surface 14, an upper surface 15, and a lower surface 16. The first inner surface reflection surface 13 and the second inner surface reflection surface 14 are substantially parallel to each other. The light guide plate 801 has N (N is an integer greater than 1) beam splitting surfaces 17 inside. The N beam splitting surfaces 17 are substantially parallel to each other.

[0050] The deflecting prism 301 is formed of a triangular prism and has a reflecting surface 302 and other surfaces 303 and 304 .

[0051] The light guide plate 801 and the deflection prism 301 are made of a medium with high transparency. The material of the light guide plate 801 and the deflection prism 301 can be glass or resin, for example. In addition, in order to prevent multiple images from being displayed, the material of the light guide plate 801 and the deflection prism 301 does not have birefringence or has little birefringence.

[0052] The image deflection unit 210 is integrated with the light guide unit 230 or optically bonded to the light guide unit 230. Figure 5In the embodiment, the second inner surface reflection surface 14 of the light guide plate 801 and the surface 303 of the deflection prism 301 are optically bonded to each other. The bonding of the light guide plate 801 and the deflection prism 301 can be performed by a transparent adhesive material or by inorganic bonding (optical contact). When the light guide plate 801 and the deflection prism 301 are bonded by an adhesive, the adhesive is prevented from overflowing to the portion of the second inner surface reflection surface 14 that is not in contact with the surface 303. Thus, it is possible to prevent the image quality from being degraded due to image blurring or blurring caused by the overflowing adhesive.

[0053] Figure 6 The figures show an example of propagation of image light emitted from the image projection unit 200. (a) is an overall view of the light guide plate 801 and the deflection prism 301, and (b) and (c) are partial enlarged views.

[0054] like Figure 6 As shown in (a), the image light emitted from the image projection unit 200 is incident on the light guide plate 801 from the first inner surface reflection surface 13, passes through the bonding portion between the light guide plate 801 and the deflection prism 301, and is incident on the deflection prism 301. In the deflection prism 301, the image light is reflected and deflected by the reflection surface 302. The deflected image light passes through the bonding portion between the light guide plate 801 and the deflection prism 301 and is incident on the light guide plate 801 again. At this time, since the light guide plate 801 and the deflection prism 301 are bonded, total reflection does not occur at the boundary between the light guide plate 801 and the deflection prism 301, and the image light is reliably transmitted to the light guide plate 801.

[0055] The image light incident on the light guide plate 801 again is totally reflected between the first inner surface reflection surface 13 and the second inner surface reflection surface 14, and propagates inside the light guide plate 801. The light propagating inside the light guide plate 801 is incident on the N beam splitting surfaces 17. In the beam splitting surface 17, a part of the incident light is reflected, and is emitted to the outside of the light guide plate 801 by passing through the second inner surface reflection surface 14. The remaining incident light passes through the beam splitting surface 17. The user can visually confirm the image by sensing the light reflected by the beam splitting surface 17 and emitted from the light guide plate 801 through the second inner surface reflection surface 14.

[0056] The N beam splitting surfaces 17 and the terminal surface 12 can be arranged substantially parallel to each other to form the light guide plate 801. This simplifies the manufacturing process of the light guide plate 801 and reduces the cost.

[0057] Generally, the refractive index of optical media such as glass and resin varies according to wavelength. Therefore, even if the same incident angle is incident on the optical medium, if the wavelength is different, the refractive angle is also different (dispersion). Therefore, from the time when the image light is incident on the light guide plate 801 after being emitted by the image projection unit 200 to the time when the image light is emitted by the light guide plate 801 and reaches the user's eyes, there is a problem of chromatic aberration and image distortion due to the dispersion in the propagation of light. Therefore, the method of reducing chromatic aberration and image distortion in this embodiment is described.

[0058] The refractive index of the optical material constituting the image deflection unit 210 is substantially equal to the refractive index of the optical material constituting the light guide unit 230. For example, the refractive index of the optical material of the deflection prism 301 is substantially equal to the refractive index of the optical material of the light guide plate 801. Thus, chromatic aberration and image distortion caused by dispersion when propagating from the light guide plate 801 to the deflection prism 301 and when propagating from the deflection prism 301 to the light guide plate 801 can be reduced.

[0059] In addition, if Figure 6 As in the example of the light beam shown in (a) of FIG. 1 , the light guide plate 801 and the deflection prism 301 are configured so that the image light emitted from the image projection unit 200 and then incident on the light guide plate 801 approximately vertically is emitted from the light guide plate 801 approximately vertically. Specifically, the angle 401 formed by the reflection surface 302 and the surface 303 and the angle 400 formed by the second inner surface reflection surface 14 and the beam splitting surface 17 are made approximately equal. Thus, regardless of the wavelength of the light and the incident angle to the light guide plate 801, the exit angle from the light guide plate 801 is approximately equal to the incident angle to the light guide plate 801, so that the dispersion is approximately eliminated, and the chromatic aberration and image distortion caused by the dispersion can be reduced.

[0060] Figure 6 (b) shows a light beam that propagates inside the light guide plate 801 and the deflection prism 301 after being emitted from the image projection unit 200. In this example, the light beam emitted from the image projection unit 200 is not blocked by the first inner surface reflection surface 13 and passes through the first inner surface reflection surface 13. In addition, the light beam that passes through the first inner surface reflection surface 13 is not incident on the end surface 11, but is incident on the deflection prism 301. In addition, the light beam deflected by the reflection surface 302 of the deflection prism 301 is not incident on the surface 304, but is incident on the light guide plate 801 again.

[0061] Figure 6 (c) shows an example which is not preferred for comparison. In this example, the light 310 is blocked by the first inner surface reflection surface 13 and does not pass through the first inner surface reflection surface 13. In addition, the light 311 is incident on the end surface 11. In addition, the light 312 is incident on the surface 304.

[0062] according to Figure 6The structure of (b) can avoid Figure 6 The unpreferable light condition shown in (c) is used to improve the utilization efficiency of image light or to suppress the degradation of image quality such as dark lines in the image visually confirmed by the user.

[0063] And, in Figure 5 In the embodiment, at least one or all of the end surface 11, the terminal surface 12, the upper surface 15, the lower surface 16 of the light guide plate 801, the surface 304, the upper surface 305, and the lower surface 306 of the deflection prism 301 are preferably subjected to at least one or both of frosting or black coating. In this way, it is possible to suppress the degradation of image quality caused by stray light.

[0064] Next, various modifications of this embodiment are possible and will be described.

[0065] Based on Figure 5 and Figure 6 In the above description, the image light emitted from the image projection unit 200 is incident on the light guide plate 801 from the first inner surface reflection surface 13 of the light guide plate 801, but the present invention is not limited thereto.

[0066] Figure 7 This is a diagram showing a configuration in which the arrangement of the image projection unit 200 is changed. In this example, the image light emitted from the image projection unit 200 is incident on the light guide plate 801 from the second inner surface reflection surface 14 of the light guide plate 801. This can improve the degree of freedom in designing the image display device 101.

[0067] Based on Figure 5 and Figure 6 In the above description, the light guide plate 801 and the deflection prism 301 are bonded to each other, but the present invention is not limited thereto.

[0068] Figure 8 1 is a diagram showing other structures of a light guide plate and a deflection prism. (a), (b), and (c) are a front view, a top view, and a side view, respectively. In this example, a deflection prism integrated light guide plate 802 is used, in which the light guide plate and the deflection prism are integrated. Thus, the man-hours for bonding the light guide plate 801 to the deflection prism 301 can be reduced.

[0069] Based on Figure 5 and Figure 6 In the above description, it is described that the image light emitted from the image projection unit 200 once passes through the light guide plate 801 and then enters the deflection prism 301, but the present invention is not limited thereto.

[0070] Fig. 91 is a diagram showing other structures of a light guide plate and a deflection prism, which are represented by a light guide plate 803 and a deflection prism 331. The deflection prism 331 includes an incident surface 334, a reflection surface 332, and a surface 333. The surface 333 of the deflection prism 331 is bonded to the end surface 11 of the light guide plate 803 by a transparent adhesive or inorganic bonding. The image light emitted from the image projection unit 200 is incident on the deflection prism 331. The image light incident on the deflection prism 331 is reflected and deflected by the reflection surface 332, and is incident on the light guide plate 803 via the bonding portion between the surface 333 of the deflection prism 331 and the end surface 11 of the light guide plate 803. As a result, the degree of freedom in designing and manufacturing the image display device 101 can be improved.

[0071] The refractive index of the optical material of the deflecting prism 331 is substantially equal to the refractive index of the optical material of the light guide plate 803. Thus, chromatic aberration and image distortion caused by dispersion when light propagates from the deflecting prism 331 to the light guide plate 803 can be reduced.

[0072] In addition, the light guide plate 803 and the deflection prism 331 are configured so that the image light emitted from the image projection unit 200 and then incident on the deflection prism 331 approximately vertically is emitted from the light guide plate 803 approximately vertically after propagating in the light guide plate 803. Specifically, the angle 402 formed by the reflection surface 332 and the incident surface 334 and the angle 400 formed by the second inner surface reflection surface 14 and the beam splitting surface 17 are made approximately equal. Thus, regardless of the wavelength of the light and the incident angle to the light guide plate 803, the output angle from the light guide plate 803 is approximately equal to the incident angle to the deflection prism 331, so that the dispersion is approximately eliminated, and the chromatic aberration and image distortion caused by the dispersion can be reduced.

[0073] Fig.10 8 is a diagram showing another structure of a light guide plate and a deflection prism, and is shown by a light guide plate 804 and a deflection prism 341. The end face 11 of the light guide plate 804 is substantially parallel to the beam splitting surface 17. This can reduce the manufacturing difficulty of the light guide plate 804 and reduce the cost of the light guide plate 804.

[0074] Fig.11 805 is a diagram showing another structure of a light guide plate and a deflection prism, in which the light guide plate and the deflection prism are integrated. The deflection prism integrated light guide plate 805 serves as both the light guide plate and the deflection prism, and the end surface 11 of the light guide plate 805 also serves as a reflection surface of the image deflection unit 210.

[0075] The image light emitted from the image projection unit 200 enters the light guide plate 805 from the first inner surface reflection surface 13. The image light entering the light guide plate 805 is reflected and deflected by the end surface 11, and is totally reflected inside the light guide plate 805 and propagates.

[0076] The end face 11 of the light guide plate 805 is configured to be substantially parallel to the beam splitting surface 17. Thus, regardless of the wavelength of light and the incident angle to the light guide plate 805, the exit angle from the light guide plate 805 is substantially equal to the incident angle to the light guide plate 805. Thus, dispersion is substantially eliminated, and chromatic aberration and image distortion caused by dispersion can be reduced. By adopting a light guide plate 805 with an integrated deflection prism, the manufacturing difficulty can be reduced, and the number of components can be reduced, which can reduce costs.

[0077] In the above configuration, the light guide unit 230 is described as a light guide plate having one or more beam splitting surfaces 17 therein, but the present invention is not limited thereto.

[0078] Fig.12 : This is a diagram showing other structures of a light guide plate and a deflection prism, and is an example of using a volume hologram type light guide plate 810 as a light guide plate. The volume hologram type light guide plate 810 has covering layers 811, 812 and a dielectric layer 813. The covering layers 811, 812 are, for example, flat plates such as glass and resin. The covering layer 811 has a first inner surface reflection surface 814, and the covering layer 812 has a second inner surface reflection surface 815. The second inner surface reflection surface 815 of the volume hologram type light guide plate 810 and the surface 303 of the deflection prism 301 are bonded by a transparent adhesive or inorganic bonding. At least a portion of the dielectric layer 813 has a hologram material. Multiple exposures are performed on the hologram material in advance, and a predetermined hologram is recorded.

[0079] The image light emitted from the image projection unit 200 enters the volume hologram type light guide plate 810 from the first inner surface reflection surface 814, propagates inside, and enters the deflection prism 301. The light incident on the deflection prism 301 is reflected and deflected by the reflection surface 302, and enters the volume hologram type light guide plate 810 again. The image light incident on the volume hologram type light guide plate 810 again propagates inside the volume hologram type light guide plate 810 while being totally reflected by the first inner surface reflection surface 814 and the second inner surface reflection surface 815. The image light propagating inside the volume hologram type light guide plate 810 is diffracted by the hologram of the hologram material recorded on the medium layer 813, and is emitted from the volume hologram type light guide plate 810. The user can visually recognize the image by perceiving a part of the image light emitted from the volume hologram type light guide plate 810.

[0080] As described above, according to Example 1, a light guide plate-type image display device 101 and an image display system 100 can be provided, which can reduce chromatic aberration and image distortion caused by dispersion when the image light is incident on the light guide plate and the deflection prism, or emitted from the light guide plate and the deflection prism, and can display high-quality images.

[0081] Example 2

[0082] In the second embodiment, the optical axis of the image light emitted from the image projection unit 200 is not perpendicular to the second inner surface reflection surface of the light guide plate. In the second embodiment, the differences from the above embodiment are mainly described, and the same reference numerals are given to the same structures as the above embodiment, and their description is omitted.

[0083] Fig.13 1 is a diagram showing the structure of the image deflection unit 210 and the light guide unit 230 of Example 2. (a), (b), and (c) are a front view, a top view, and a side view, respectively. The image deflection unit 210 includes a deflection prism 502, and the light guide unit 230 includes a light guide plate 801. In addition, a correction prism 503 is bonded to the light guide plate 801. Preferably, the correction prism 503 is bonded to the light guide plate 801 by a transparent adhesive or inorganic bonding.

[0084] The image light emitted from the image projection unit 200 enters the correction prism 503 , propagates inside, and then enters the light guide plate 801 from the joint portion between the correction prism 503 and the light guide plate 801 .

[0085] The refractive index of the optical material of the correction prism 503 is substantially equal to the refractive index of the optical material of the light guide plate 801. In addition, the refractive index of the optical material of the deflection prism 502 is substantially equal to the refractive index of the optical material of the light guide plate 801. As a result, when light propagates from the correction prism 503 to the light guide plate 801, when light propagates from the light guide plate 801 to the deflection prism 502, and when light propagates from the deflection prism 502 to the light guide plate 801, chromatic aberration and image distortion caused by dispersion can be reduced.

[0086] In addition, if Fig.13 As in the example of the light beam shown in (b) of FIG. 1 , the light guide plate 801, the deflection prism 502, and the correction prism 503 are configured in such a manner that the image light emitted from the image projection unit 200 and incident on the correction prism 503 approximately vertically is emitted approximately vertically from the light guide plate 801. Specifically, when the angle formed by the second inner surface reflection surface 14 and the beam splitter surface 17 is set to an angle of 400, the vertex angle of the deflection prism 502 is set to an angle of 504, and the vertex angle of the correction prism 503 is set to an angle of 505, the following relationship is approximately established.

[0087] (Angle 505) = 2 × (Angle 400) - 2 × (Angle 504)

[0088] Therefore, regardless of the wavelength of light and the incident angle to the correction prism 503, the output angle from the light guide plate 801 is approximately equal to the incident angle to the correction prism 503, so dispersion is approximately eliminated, which can reduce chromatic aberration and image distortion caused by dispersion.

[0089] Next, various modifications of this embodiment are possible and will be described.

[0090] Fig.14 2 is a diagram showing another configuration of the image deflection unit 210 and the light guide unit 230. The light guide unit 230 includes a light guide plate 820, and the light guide plate 820 includes an input surface 821. Image light emitted from the image projection unit 200 enters the light guide plate 820 from the input surface 821 thereof.

[0091] like Fig.14 As in the example of the light beam shown in (b) of FIG. 1 , the light guide plate 820 and the image deflection unit 210 are configured in such a manner that the image light emitted from the image projection unit 200 and incident approximately perpendicularly on the input surface 821 of the light guide plate 820 is emitted approximately perpendicularly to the outside from the light guide plate 820. Specifically, when the angle formed by the second inner surface reflection surface 14 and the beam splitting surface 17 is set to an angle of 400, the vertex angle of the deflection prism 502 is set to an angle of 504, and the angle formed by the input surface 821 and the second inner surface reflection surface 14 is set to an angle of 506, the following relationship is substantially established.

[0092] (Angle 506) = 2 × (Angle 400) - 2 × (Angle 504)

[0093] Therefore, regardless of the wavelength of light and the incident angle to the light guide plate 820, the output angle from the light guide plate 820 is substantially equal to the incident angle to the light guide plate 820, so that dispersion is substantially eliminated, and chromatic aberration and image distortion caused by dispersion can be reduced.

[0094] Fig.15 2 is a diagram showing other structures of the image deflection unit 210 and the light guide unit 230. The light guide unit 230 includes a light guide plate 803, and the image deflection unit 210 includes a deflection prism 511. The image light emitted from the image projection unit 200 is incident from the incident surface 512 of the deflection prism 511, is reflected and deflected at the reflection surface 513 of the deflection prism 511, and is incident on the light guide plate 803 through the bonding portion between the deflection prism 511 and the light guide plate 803.

[0095] like Fig.15 As in the example of the light beam shown in (b) of FIG. 1 , the light guide plate 803 and the image deflection unit 210 are configured such that the image light emitted from the image projection unit 200 and incident approximately perpendicularly on the incident surface 512 of the deflection prism 511 is emitted approximately perpendicularly from the light guide plate 803. Specifically, when the angle formed by the second inner surface reflection surface 14 and the beam splitting surface 17 is set to an angle of 400, the angle formed by the reflection surface 513 and the second inner surface reflection surface 14 is set to an angle of 514, and the angle formed by the incident surface 512 and the second inner surface reflection surface 14 is set to an angle of 515, the following relationship is substantially established.

[0096] (Angle 515) = 2× (Angle 400) – 2× (Angle 514)

[0097] Therefore, regardless of the wavelength of light and the incident angle to the incident surface 512 of the deflection prism 511, the output angle from the light guide plate 803 is approximately equal to the incident angle to the incident surface 512 of the deflection prism 511, so dispersion is approximately eliminated, which can reduce chromatic aberration and image distortion caused by dispersion.

[0098] According to the second embodiment, the optical axis of the image light emitted from the image projection unit 200 can be set at an angle different from the angle perpendicular to the second inner surface reflection surface of the light guide plate, thereby improving the degree of freedom in designing the image display device 101.

[0099] Example 3

[0100] In the third embodiment, the image deflection unit 210 is configured to have a light beam copying function. In the third embodiment, the differences from the above embodiment will be mainly described, and the same reference numerals are given to the same structures as the above embodiment, and their description will be omitted.

[0101] Fig.16 1 is a diagram showing the structure of the image deflection unit 210 and the light guide unit 230 of Example 3. (a), (b), and (c) are a front view, a top view, and a side view, respectively, and (d) is a partial enlarged view of (b). The image deflection unit 210 includes a light replicating deflection prism 601, and the light guide unit 230 includes a light guide plate 801. The light replicating deflection prism 601 is composed of two substrates 602 and 603, which are bonded by a transparent adhesive or inorganic bonding. The light replicating deflection prism 601 includes a reflecting surface 604 and a beam splitting surface 605, and the reflecting surface 604 is substantially parallel to the beam splitting surface 605.

[0102] The image light emitted from the image projection unit 200 passes through the light guide plate 801 and enters the light copy deflection prism 601. A portion of the image light incident on the light copy deflection prism 601 is reflected by the beam splitting surface 605, and a portion passes through the beam splitting surface 605. The image light reflected by the beam splitting surface 605 is incident on the light guide plate 801 again. The image light that has passed through the beam splitting surface 605 is reflected by the reflection surface 604. A portion of the image light reflected by the reflection surface 604 passes through the beam splitting surface 605 and enters the light guide plate 801 again. In this way, by copying the light by the light copy deflection prism 601, the pupil of the image light can be copied, and the distribution of the image light output from the light guide plate 801 can be made more uniform. As a result, the uniformity of the image visually recognized by the user can be improved.

[0103] The reflectivity of the beam splitter 605 is preferably 10% to 90%, and more preferably 10% to 50%. This can suppress the variation in the intensity ratio of the copied image light, and improve the uniformity of the image visually recognized by the user.

[0104] In the above description, the light replicating and deflecting prism 601 is described as having one beam splitting surface 605, but the present invention is not limited thereto. The light replicating and deflecting prism 601 may also have two or more beam splitting surfaces 605 that are substantially parallel to each other. In this way, the uniformity of the image visually recognized by the user can be further improved.

[0105] The surface 606 of the light replicating and deflecting prism 601 is preferably subjected to either frosting or black coating or both, thereby reducing the generation of stray light.

[0106] According to the third embodiment, by providing the image deflection unit 210 with a light beam duplication function, it is possible to provide a light guide plate type image display device 101 and an image display system 100 that allow a user to visually recognize a more uniform image.

[0107] Example 4

[0108] In Embodiment 4, the image display device 101 is configured to include a pupil expansion unit. In Embodiment 4, differences from the above-described embodiment will be mainly described, and the same reference numerals are given to the same components as those in the above-described embodiment, and their description will be omitted.

[0109] Fig.17 1 is a diagram showing the structure of the image display device 101 of Example 4. (a), (b), and (c) are a front view, a top view, and a side view, respectively. The image display device 101 includes a pupil expansion unit 700 between the image projection unit 200, the image deflection unit 210, and the light guide unit 230. Here, the image deflection unit 210 includes a deflection prism 301, and the light guide unit 230 includes a light guide plate 801. In addition, the pupil expansion unit 700 includes a pupil expansion prism 701.

[0110] like Fig.17 As shown in (c), the pupil expansion prism 701 includes an input surface 702 of the image light, one or more beam splitting surfaces 703, and an output surface 704. The beam splitting surfaces 703 are substantially parallel to each other. The output surface 704 of the pupil expansion prism 701 and the first inner surface reflection surface 13 of the light guide plate 801 may be bonded by a transparent adhesive or inorganic bonding, or may be arranged at a predetermined interval without bonding.

[0111] The image light emitted from the image projection unit 200 is incident on the pupil expansion prism 701 from the input surface 702. The light incident on the pupil expansion prism 701 is incident on the beam splitting surface 703, and at least a part of the light is reflected by the beam splitting surface 703. At least a part of the unreflected light passes through the beam splitting surface 703 and is incident on the next beam splitting surface 703. In this way, the light reflected by each beam splitting surface 703 is emitted from the output surface 704 and is incident on the light guide plate 801 from the first inner surface reflection surface 13.

[0112] According to the fourth embodiment, by replicating the image light output by the image projection unit 200, the range in which the user can visually recognize the image, i.e., the visible area (eyebox), can be expanded even if the relative positions of the user's eyes and the image display device 101 are misaligned. That is, it is possible to provide an image display device 101 and an image display system 100 of a light guide plate type with a large visible area.

[0113] Example 5

[0114] In the fifth embodiment, the video display system 100 is configured to compensate for dispersion by the image signal processing unit 104. In the fifth embodiment, the differences from the above embodiments are mainly described, and the same reference numerals are given to the same structures as the above embodiments, and their description is omitted.

[0115] Fig.18 1 is a diagram showing the structure of the image display device 101 according to Example 5. A deflection prism 502 is provided as the image deflection unit 210 , and a light guide plate 801 is provided as the light guide unit 230 .

[0116] Among the image light emitted from the image projection unit 200, the light incident on the light guide plate 801 at an angle other than perpendicular is emitted substantially perpendicularly from the light guide plate 801. In this case, chromatic aberration and image distortion may occur due to dispersion. Specifically, there may be a case where the image is offset (displaced) and output due to colors such as red, green, and blue, or the aspect ratio of the image output from the light guide plate 801 is different.

[0117] Fig.19 901 and 902 are diagrams showing a configuration for correcting chromatic aberration and image distortion by the image signal processing unit 104 in this embodiment. The image signal processing unit 104 includes an enlargement / reduction unit 901 and a shift unit 902.

[0118] The image signal input to the image signal processing unit 104 is input to the magnification and reduction unit 901 and converted into an image signal after the image is magnified and reduced. The magnification and reduction of the image by the magnification and reduction unit 901 can be performed linearly or nonlinearly. The image signal output from the magnification and reduction unit 901 is input to the shift unit 902 and converted into an image signal in which the image is shifted. The image signal after the image is shifted is output from the image signal processing unit 104. The amount of magnification and reduction of the image by the magnification and reduction unit 901 and the amount of shift of the image by the shift unit 902 are approximately equal to the amount of compensating for the chromatic aberration and image distortion of the image caused by refraction and dispersion from the time of being incident on the light guide plate 801 to being output from the light guide plate 801. In particular, in order to correct the chromatic aberration and image distortion caused by dispersion, the magnification and reduction amount and the shift amount may be different according to R, G, and B of the image signal.

[0119] In addition, the image signal processing section 104 may include both the enlargement and reduction section 901 and the shift section 902 , or may include one of them. Thus, the processing load of the image signal processing section 104 can be reduced.

[0120] According to the fifth embodiment, it is possible to provide a light guide plate type image display device 101 and an image display system 100, which can display high-quality images by correcting chromatic aberration and image distortion caused by dispersion through the image signal processing unit 104. In addition, the incident angle of the image light from the image projection unit 200 to the light guide plate 801 can be an angle other than vertical, thereby increasing the degree of freedom in the design of the image display device.

[0121] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various variations and equivalent structures within the gist of the technical solutions for which patent protection is requested. For example, the above-mentioned embodiments are described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the structures described. In addition, a part of the structure of a certain embodiment may be replaced with the structure of other embodiments. In addition, the structure of other embodiments may be added to the structure of a certain embodiment. In addition, other structures may be added, deleted, or replaced with a part of the structure of each embodiment.

[0122] In addition, part or all of the above-mentioned structures, functions, processing parts, processing units, etc. can be implemented by hardware, such as through integrated circuit design, or by software by interpreting and executing programs that implement each function by a processor.

[0123] Information such as programs, tables, and files that realize various functions can be stored in a storage device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

[0124] In addition, the control lines and information lines are shown as those considered necessary for explanation, and are not limited to showing all the control lines and information lines required for installation. In fact, it can be considered that almost all the structures are connected to each other.

[0125] Explanation of symbols

[0126] 17: beam splitter, 100: image display system, 101: image display device, 102: controller, 104: image signal processing unit, 105: power supply unit, 106: storage medium, 107: sensing unit, 108: sensor input and output unit, 109: communication unit, 111: sound processing unit, 120: user's eyes, 200: image projection unit, 210: image deflection unit, 220: light guide plate, 221: light input unit, 222: light output unit, 223: inner surface reflection surface, 224: inner surface reflection surface, 230: guide Optical part, 301, 331, 341, 502: deflection prism, 503: correction prism, 511: deflection prism, 601: light replicating deflection prism, 605: beam splitting surface, 700: pupil expansion part, 701: pupil expansion prism, 703: beam splitting surface, 801: light guide plate, 802: deflection prism integrated light guide plate, 803~804: light guide plate, 805: deflection prism integrated light guide plate, 810: volume holographic light guide plate, 813: dielectric layer, 820: light guide plate, 901: magnification and reduction part, 902: displacement part.

Claims

1. An image display device for displaying an image, characterized in that: have: An image projection unit that projects image light; an image deflection unit; and A light guide having a plurality of beam splitting surfaces substantially parallel to each other arranged inside, and comprising an input surface and a second inner surface reflection surface, The image deflection unit deflects the image light emitted by the image projection unit and transmits the image light to the light guide unit. The light guide portion allows the incident image light to propagate inside and output. The refractive index of the optical material constituting the image deflection unit is equal to the refractive index of the optical material constituting the light guide unit. The image light emitted from the image projection unit is incident from the input surface of the light guide unit, and is emitted from the second inner surface reflection surface of the light guide unit. After passing through the light guide unit, the image light is incident from the incident surface of the image deflection unit to the image deflection unit. After being reflected and deflected by the reflection surface of the image deflection unit, the image light is incident on the light guide unit again. The light propagating in the light guide unit is incident on the plurality of beam splitting surfaces, and a part of the incident light is reflected and emitted to the outside of the light guide unit by passing through the second inner surface reflection surface. When the angle generated by the second inner surface reflection surface of the light guide part and the beam splitting surface is a first angle, the vertex angle formed by the incident surface of the image deflection part and the reflection surface of the image deflection part is a second angle, and the angle formed by the input surface of the light guide part and the second inner surface reflection surface is a fourth angle, the relationship of fourth angle = 2×first angle - 2×second angle is established.

2. The image display device according to claim 1, characterized in that: The image deflection unit is integrated with the light guide unit or the image deflection unit is optically bonded to the light guide unit.

3. The image display device according to claim 1, characterized in that: The image light emitted from the image projection unit and incident substantially vertically on the light guide unit is output substantially vertically from the light guide unit.

4. The image display device according to claim 1 or 2, characterized in that: The image display device includes an image copying unit. The image copying unit includes two or more partially reflecting surfaces that are substantially parallel to each other and reflect at least a portion of light, and copies incident image light to output two or more image lights.

5. The image display device according to claim 4, characterized in that: The image light emitted from the image projection unit and incident substantially vertically on the image reproduction unit is output substantially vertically from the light guide unit.

6. An image display device for displaying an image, characterized in that: have: An image projection unit that projects image light; Image deflection unit; A light guide having a plurality of substantially parallel beam splitting surfaces disposed therein, including a first inner surface reflection surface and a second inner surface reflection surface substantially parallel to each other; and Correction prism; The refractive index of the optical material constituting the image deflection unit is equal to the refractive index of the optical material constituting the light guide unit. The image light emitted from the image projection unit enters the correction prism from the incident surface of the correction prism, is emitted from the emission surface of the correction prism, and then enters the first inner surface reflection surface of the light guide unit after passing through the correction prism, and is emitted from the second inner surface reflection surface of the light guide unit. Then, after passing through the light guide unit, the image light enters the incident surface of the image deflection unit, is reflected and deflected by the reflection surface of the image deflection unit, and then enters the light guide unit again. The light propagating in the light guide unit enters the plurality of beam splitting surfaces, and a part of the incident light is reflected and is emitted to the outside of the light guide unit by passing through the second inner surface reflection surface. When the angle generated by the second inner surface reflection surface of the light guide part and the beam splitting surface is a first angle, the vertex angle formed by the incident surface of the image deflection part and the reflection surface of the image deflection part is a second angle, and the vertex angle formed by the incident surface of the correction prism and the output surface of the correction prism is a third angle, the relationship of the third angle = 2×first angle - 2×second angle is established.

7. An image display system, characterized in that: have: The image display device according to any one of claims 1 to 6; and The image signal processing unit generates a projection image signal used by the image projection unit to project image light.

8. The image display system according to claim 7, characterized in that: The image signal processing unit performs image processing to compensate for dispersion caused by the image deflection unit and the light guide unit.

9. The image display system according to claim 8, characterized in that: The image signal processing unit performs image processing such as enlarging or reducing an image, shifting an image, or both.

Images