Light guide and virtual image display device

Abstract

The present invention relates to a light guide and a virtual image display device. The light guide (300, 3000, 4000) comprises a light guide member (310, 320) having first and second light guide members (310, 320), a light incident portion (8, 108, 301) having a surface for incident light, a light guide unit (30, 130, 302) for guiding light incident on the light incident portion (8, 108, 301) by repeated reflection, a light emitting unit (40, 140, 304) for emitting light to the outside of the light guide (300, 3000, 4000), and an extraction unit (5, 303, 303A, 303B, 303C) for reflecting the light guided by the light guide unit (30, 130, 302) toward the light emitting unit (40, 140, 304). The light guide components (310, 320) guide and emit light, and the second light guide component (320) is at least connected to the light guide unit (30, 130, 302) of the first light guide component (310).

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a light guide and a virtual image display device. Background Art

[0002] As a virtual image display device, for example, a head-mounted display (HMD) is generally used. This head-mounted display (HMD) is divided into a transparent type and an opaque type. For example, in the art, as a transparent perspective HMD, Google Glass (registered trademark) is well-known, and images can be seen through this perspective HMD. Various opaque HMDs that realize deep immersive simulation have also been released by many companies. Regarding the size of the virtual image visually recognized by a person through a virtual image display device, a transparent HMD is used in combination with an external information terminal, or in combination with augmented reality (AR) technology. For this reason, a small and portable HMD is required. On the contrary, an opaque HMD is used, for example, for games or virtual reality (VR) technology. For this reason, it is expected to achieve an immersive and wide viewing angle HMD. Some common characteristics of virtual image display devices are given below. The viewing angle of a virtual image display device dedicated to miniaturization of the main body and reduction of thickness will tend to be narrow. On the contrary, when the viewing angle of the display area becomes wider, the size of the main body of the virtual image display device will tend to increase, and its thickness will tend to increase. Currently, a transparent type HMD having a reduced thickness is required, and a wide viewing angle is also required for such a transparent type HMD having a reduced thickness.

[0003] Technologies that meet these requirements are known in the art (see, for example, patent documents 1 to 3). However, in such technologies known in the art, when light is emitted to the outside of the optical conductor by reflection from multiple reflectors or multiple tiny components, the light is guided to the user's eyes. In such a technology or configuration, some light rays guided through the light guide at varying angles corresponding to multiple pixels of an image formed by an image display element do not collide with any of the multiple reflectors or multiple tiny components. In view of these circumstances, brightness loss errors may occur in the observed virtual image.

[0004] In order to solve the above technical problems, the following method for preventing the missing error of brightness has been proposed (for example, see Patent Document 4). In this method for preventing the missing error of brightness, a light splitting layer is set inside the light guide, and the timing of reflecting light with different angles guided by the light guide plate is adjusted. Due to this structure, light with an angle that is likely to cause the missing error of brightness is likely to hit multiple reflectors or multiple tiny components.

[0005] As a device that magnifies a two-dimensional (2D) image through a virtual image optical system and displays the magnified virtual image so that an observer or user can observe the displayed magnified virtual image, a virtual image display device having a light guide is known in the art. As a configuration example of such a virtual image display device having a light guide, a head-mounted display (HMD) is known in the art. Such head-mounted displays (HMD) are classified into transparent HMDs and opaque HMDs. For example, Google Glass (a registered trademark of Google LLC, USA) is well known in the art as a transparent see-through HMD through which images can be seen.

[0006] This transparent see-through HMD is used in combination with an external information terminal, or, for example, in combination with augmented reality (AR) technology. For this reason, a small and portable HMD is required. When, for example, watching a movie, playing a game, or providing virtual reality (VR) technology, an opaque HMD is used. For this reason, it is desirable to achieve an immersive and wide viewing angle HMD.

[0007] In a transparent HMD, it is desired to reduce thickness, reduce size, and wide viewing angle. In addition, it is desired to prevent a decrease in transmittance of external light or a decrease in reflectance of light from occurring, and to prevent the formation of ghost images. As features that meet such requirements, a light guide plate and a virtual image display device having the light guide plate disclosed in Patent Document 3 are known in the art.

[0008] The light guide plate disclosed in Patent Document 3 includes a first total reflection surface and a second total reflection surface facing each other and extending in the same direction. The light guide plate disclosed in Patent Document 3 turns the light path between the pair of reflection surfaces and guides the light toward a light emitting unit having an image extraction unit. The image extraction unit includes a plurality of first planes and a plurality of second planes, wherein the plurality of first planes extend obliquely toward the inner side of the light guide unit at the far side of the image extraction unit in the light guiding direction, and the plurality of second planes form an obtuse angle with the plurality of first planes. The plurality of first planes and the plurality of second planes are alternately arranged. The light guide plate constructed as described above can be used to realize a virtual image display device.

[0009] When the light guide plate disclosed in Patent Document 3 is used to achieve a wide viewing angle, a problem known in the art is that uneven brightness or brightness loss errors occur on the virtual image. Fig.39 The reasons why brightness non-uniformity or brightness loss errors occur on a virtual image will be described using a comparative example of a light guide plate disclosed in Patent Document 3.

[0010] like Fig.39As shown, the light guide plate is a horizontally oriented plate-shaped member made of a transparent material. For example, such a light guide plate is placed in front of a person's eyes like a pair of glasses. By using such a light guide plate, an image can be observed by the light emitted from the light emitting unit, and a scene in front of the light guide plate can be observed by the light passing through the light guide plate. Fig.39 In the figure, the direction perpendicular to the paper plane represents the up and down direction of the light guide plate under normal operating conditions, and these directions are called X directions. Fig.39 The up and down direction in the system is called the Y direction. In other words, the forward and backward directions under the use condition are called the Y direction. Fig.39 The left-right direction in the image and the direction perpendicular to both the X direction and the Y direction is called the Z direction.

[0011] like Fig.39 The light guide plate shown in the figure has a light incident portion 108 shown on the lower left side and a light emitting unit 140 shown on the lower right side. In addition, a light guide unit 130 is shown between the light incident portion 108 and the light emitting unit 140. The light incident portion 108 includes a prism 111 on which light is incident, and includes a reflector 101 that reflects the incident light that has passed through the prism 111 toward the light guide unit 130.

[0012] The light guide unit 130 involved in the comparative example includes a first reflection surface 102 and a second reflection surface 103, which are parallel to each other and alternately and sequentially reflect the light reflected by the reflector 101 in a zigzag manner to guide the light to the light emitting unit 140. The function of the portion of the second reflection surface 103 facing the light emitting unit 140 is to serve as a plurality of image extraction units 105 and a plurality of sub-reflection surfaces 133. These image extraction units 105 and the plurality of sub-reflection surfaces 133 are alternately arranged in the Z direction.

[0013] Each of the plurality of image capturing units 105 is an inclined surface that gradually descends at a certain angle toward the light emitting unit 140, and the plurality of sub-reflecting surfaces 133 are parallel to the first reflecting surface 102. Therefore, the thickness of the light guide plate in the front-to-back direction gradually becomes thinner toward the light emitting unit 140.

[0014] For example, light emitted from a predetermined image forming element is collimated and then incident on the light guide plate through the light incident portion 108. Then, the light is obliquely reflected toward the first reflection surface 102 by the reflector 101, and is obliquely reflected toward the second reflection surface 103 by the first reflection surface 102. As a result, the light is reflected in a zigzag manner at a certain incident angle and reflection angle between the first reflection surface 102 and the second reflection surface 103, and travels toward the light emitting unit 140.

[0015] Once the light reaches each image extraction unit 105, each of the plurality of image extraction units 105 reflects a portion of the incident light toward the light emission unit 140. The light reflected by each image extraction unit 105 passes through the light emission unit 140 and enters the eye of a person facing the light emission unit 140. The image formed by the image forming element and the like can be observed by the human eye through the light reflected by each image extraction unit 105. The light in front of the light guide plate is guided by the light emission unit 140, and the guided light is observed by the human eye. Due to this configuration, the scene in front of the light guide plate can be observed together with the above-mentioned image.

[0016] according to Fig.39 The planar light guide plate shown guides light having a wider total reflection angle with respect to the normal of the main plane of the light guide plate and light having a narrower total reflection angle with respect to the normal of the main plane of the light guide plate according to the field of view of the image. Due to this structure, when light having a wider total reflection angle on the first reflection surface 102 and the second reflection surface 103 is guided, the field of view angle of the observed virtual image can be increased, and the viewing angle can be widened.

[0017] Fig.39 The figure shows a light path diagram of light transmitted from a light incident portion 108 disposed at the left end of the light guide plate to the first reflection surface 102 and the second reflection surface 103 at a wider total reflection angle in a known light guide plate.

[0018] Citation List

[0019] Patent Literature

[0020] [Patent Document 1] Japanese Patent Application Publication No. 2013-210633

[0021] [Patent Document 2] Japanese Patent Application Publication No. 2011-509417

[0022] [Patent Document 3] Japanese Patent Application Publication No. 2011-198260

[0023] [Patent Document 4] U.S. Patent Application Publication No. 2017 / 0285346 Summary of the invention

[0024] Technical issues

[0025] However, when a layer for dividing light is provided inside the light guide, at least one dividing surface needs to be provided on the light guide. More specifically, the light guide needs to be divided into a plurality of parts, and then these parts of the light guide need to be joined to each other through the at least one dividing surface. Due to such a complex structure, the difficulty in production or manufacturing tends to increase.

[0026] As described above, when light is transmitted at a wider total reflection angle within the light guide plate, and the total reflection interval between the first reflection surface and the second reflection surface is wider, the irradiance level of the light beam reaching the plurality of image extraction units 105 becomes easy to vary, and some of the plurality of image extraction units 105 may not be partially illuminated by light. As a result, uneven brightness may appear on the virtual image observed through the light emitting unit 140. Alternatively, a brightness missing error may appear on the virtual image observable through the light emitting unit 140. In other words, some light does not reach the light emitting unit 140, which is not desired. In other words, in the case of using a light guide plate such as that described above to constitute a virtual image display device, when the viewing angle of the image becomes larger, uneven brightness or brightness missing errors may occur on the virtual image depending on the viewing angle or the position of visual recognition of the virtual image, which is not desired.

[0027] Solutions to the problem

[0028] The light guide includes two or more light guide members including a first light guide member and a second light guide member; a light incident portion having a surface for incident light; a light guide unit for guiding the light incident on the light incident portion by repeated reflection; a light emitting unit for emitting the light to the outside of the light guide, and an extraction unit for reflecting the light guided by the light guide unit toward the light emitting unit. The two or more light guide members guide and emit light, and the second light guide member is at least joined to the light guide unit of the first light guide member.

[0029] Effects of the Invention

[0030] According to one aspect of the present disclosure, missing errors in brightness can be controlled, and easy manufacturing of a light guide can be achieved.

[0031] In the light guide and virtual image display device according to the embodiment of the present disclosure, the optical path separation component is configured to be separated from the light incident portion and disposed between the first reflection surface and the second reflection surface. As a result, it is possible to reduce brightness unevenness or brightness missing errors that may occur on the virtual image to be observed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are intended to describe exemplary embodiments of the present invention and should not be interpreted as limiting its scope. Unless explicitly stated, the accompanying drawings should not be considered to be drawn to scale. In addition, in all the drawings, the same or similar reference numerals represent the same or similar components.

[0033] Figure 1 FIG. 1 is a schematic diagram of a virtual image display device having a light guide according to a first embodiment of the present disclosure.

[0034] Figure 2The figure is a partially enlarged view of the light guide body involved in the first embodiment of the present disclosure.

[0035] Figure 3 The figure shows another enlarged view of a part of the light guide body involved in the first embodiment of the present disclosure.

[0036] Figure 4 FIG. 1 is a schematic diagram of a virtual image display device having a light guide according to a comparative example of the above-mentioned embodiment of the present disclosure.

[0037] Figure 5 FIG. 1 is a diagram showing a light beam guided by a light guide according to a comparative example of the above-described embodiment of the present disclosure.

[0038] Figure 6 FIG. 2 is a diagram showing a light beam guided by a light guide according to the first embodiment of the present disclosure.

[0039] Figure 7 FIG. 1 is a schematic diagram of a light guide according to a second embodiment of the present disclosure.

[0040] Figure 8 The figure is a partially enlarged view of the light guide body involved in the second embodiment of the present disclosure.

[0041] Fig. 9 FIG. 1 is a partially enlarged view of a light guide according to a modified example of the second embodiment of the present disclosure.

[0042] Fig.10 As shown Figure 7 A diagram showing another configuration or structure of the first light guide member.

[0043] Fig.11A and Fig. 11B Shown separately Figure 7 A diagram of another configuration or structure of the extraction unit shown.

[0044] Fig.12 FIG. 1 is a schematic diagram of a light guide according to a third embodiment of the present disclosure.

[0045] Fig.13 FIG. 4 is a schematic diagram of a light guide according to a fourth embodiment of the present disclosure.

[0046] Fig.14 FIG. 1 is a diagram showing a simulation result of the brightness distribution of a virtual image in a virtual image display device according to a comparative example of the above-mentioned embodiment of the present disclosure.

[0047] Fig.15 FIG. 4 is a diagram showing a simulation result of the brightness distribution of a virtual image in a virtual image display device according to an embodiment of the present disclosure.

[0048] Fig.16 FIG. 1 is a plan view of a light guide according to a fifth embodiment of the present disclosure.

[0049] Fig.17 1 is a top view of a light guide divided into a plurality of functional areas according to a fifth embodiment of the present disclosure.

[0050] Fig.18 FIG. 1 is a plan view showing a light guiding state when light is incident on a light guide at a wide reflection angle according to a fifth embodiment of the present disclosure.

[0051] Fig.19 FIG. 1 is a plan view showing a light guiding state when light is incident on a light guide at a narrow reflection angle according to a fifth embodiment of the present disclosure.

[0052] Fig. 20 FIG. 1 is a plan view showing a light guiding state when light according to a modification example of the fifth embodiment of the present disclosure is incident on a light guide at a wide reflection angle.

[0053] Fig.21 1 is a plan view showing a light guiding state when light according to a fifth embodiment of the present disclosure is incident on a light guide at a large reflection angle and an image based on the incident light is observed as a virtual image at the center of an eye box.

[0054] Fig. 22 1 is a plan view showing a light guiding state when light according to a fifth embodiment of the present disclosure is incident on a light guide at a large reflection angle and an image based on the incident light is observed as a virtual image on the left side of the eye box.

[0055] Fig.23 1 is a plan view showing a light guiding state when light according to a fifth embodiment of the present disclosure is incident on a light guide at a large reflection angle and an image based on the incident light is observed as a virtual image on the right side of the eye box.

[0056] Fig.24 1 is a plan view showing a light guiding state when light according to a fifth embodiment of the present disclosure is incident on a light guide at a small reflection angle and an image based on the incident light is observed as a virtual image at the center of an eye box.

[0057] Fig.25 1 is a plan view showing a light guiding state when light according to a fifth embodiment of the present disclosure is incident on a light guide at a large reflection angle and an image based on the incident light is observed as a virtual image on the right side of the eye box.

[0058] Fig.26 1 is a plan view showing a light guiding state when light according to a fifth embodiment of the present disclosure is incident on a light guide at a large reflection angle and an image based on the incident light is observed as a virtual image on the left side of the eye box.

[0059] Fig. 27 FIG. 1 is a partial plan view of a light guide showing the position of an optical path separation component that does not cause an image omission error according to a fifth embodiment of the present disclosure.

[0060] Fig.28 FIG. 1 is another partial plan view of a light guide showing the position of an optical path separation component that does not cause an image missing error according to a fifth embodiment of the present disclosure.

[0061] Fig.29 FIG. 1 is a partial plan view of a light guide showing the position of an optical path separation component that generates an image missing error according to a comparative example of the fifth embodiment of the present disclosure.

[0062] Fig.30 FIG. 1 is another partial plan view of a light guide showing the position of an optical path separation component that generates an image missing error according to a comparative example of the fifth embodiment of the present disclosure.

[0063] Fig.31 FIG. 1 is another partial plan view of the light guide showing the position of the optical path separation component causing an image missing error according to a comparative example of the fifth embodiment of the present disclosure.

[0064] Fig.32 FIG. 1 is a partial plan view of a light guide showing the position of an optical path separation component that does not cause an image omission error according to a fifth embodiment of the present disclosure.

[0065] Fig.33 The figure is a partial plan view of a light guide of a light beam when there is an optical path separation component in the position where an image missing error occurs, which is involved in a control example of the fifth embodiment of the present disclosure.

[0066] Fig.34 The figure shows another partial plan view of the light guide of the light beam when there is an optical path separation component in the position where an image missing error occurs, which is involved in the control example of the fifth embodiment of the present disclosure.

[0067] Fig.35 FIG. 1 is a partial plan view of a light guide including a plurality of optical path separation components according to a sixth embodiment of the present disclosure.

[0068] Fig.36 FIG. 1 is another partial plan view of a light guide including a plurality of optical path separation components according to a sixth embodiment of the present disclosure.

[0069] Fig.37 FIG. 1 is a partial plan view of a light guide according to a sixth embodiment of the present disclosure, showing a state in which light beams are advanced when elements of the light beams are not parallel to each other.

[0070] Fig.38 FIG. 1 is a plan view of a light guide in a state where an image is observed as a virtual image according to a sixth embodiment of the present disclosure.

[0071] Fig.39 FIG. 1 is a plan view of a light guide according to a comparative example of the above-mentioned embodiment of the present disclosure.

[0072] Fig.40 FIG. 1 is a plan view of a virtual image display device to which the light guide according to the above-described embodiment of the present disclosure is applied.

[0073] Fig.41A , Fig.41B and Fig.41C FIG. 1 is a perspective view of a virtual image display device using a light guide according to the above-mentioned embodiment of the present disclosure, showing various usage states of the virtual image display device. DETAILED DESCRIPTION

[0074] Hereinafter, the light guide and virtual image display device of the embodiment of the present invention are described in detail with reference to the accompanying drawings. In view of the above teachings, various additional modifications and variations are possible. It should therefore be understood that within the scope of the appended claims, the disclosure of the present disclosure may be implemented in a manner different from that specifically described herein. For example, within the scope of the present disclosure and the appended claims, elements and / or features of different illustrative embodiments may be combined with each other and / or replaced with each other.

[0075] Figure 1 FIG. 1 is a schematic diagram of a virtual image display device 1000 having a light guide 300 according to the first embodiment of the present disclosure.

[0076] The virtual image display device 1000 according to the first embodiment of the present disclosure is equipped with an image display element 100 , an optical system 200 , and a light guide body 300 according to the first embodiment of the present disclosure.

[0077] The image display element 100 is a device that emits image light that forms an image of a virtual image projected and displayed through the light guide 300. The image display element 100 is a plate-shaped element extending in the depth direction of the drawing. Various display elements such as an organic light emitting diode (OLED) or a liquid crystal display (LCD) can be applied to the image display element 100. As long as information such as an image can be displayed, for example, a digital micromirror device (DMD) or a liquid crystal on silicon (LCoS) that is a microelectromechanical system (MEMS) in which a large number of tiny mirrors (micromirrors) are arranged on a plane can be used for the image display element 100. In this configuration, for example, a light emitting diode (LED), a laser diode (LD), or a discharge lamp can be used as a light source to illuminate the image display element 100 with light.

[0078] The optical system 200 involved in this embodiment is composed of, for example, a plurality of optical lenses and apertures, and collimates the light beam emitted from the image display element 100 and including image data, and changes the angle of the light beam emitted from the image display element 100 and including image data to a direction consistent with each position of the image display element 100. In the following description, the light beam including image data is sometimes simply referred to as image light.

[0079] The light guide 300 used in the virtual image display device 1000 guides the image light emitted from the image display element 100 and then collimated by the optical system 200 including the image data, and emits the image light to the human eye. As a result, a virtual image is displayed. The light guide 300 is a plate-shaped member extending in the depth direction of the drawing. The light guide 300 involved in the present embodiment includes a light incident portion 301, a light guide unit 302, an extraction unit 303, and a light emitting unit 304. In addition, the light guide 300 involved in the present embodiment includes a reflection portion 305. The light incident portion 301, the light guide unit 302, the extraction unit 303, the light emitting unit 304, and the reflection portion 305 extend in the depth direction of the drawing. In the embodiment as Figure 1 In the long side direction of the light guide 300 in the left-right direction, in the following description, the side where the light incident portion 301 is arranged is sometimes referred to as the base end side, and the side away from the light incident portion 301 is sometimes referred to as the front end side.

[0080] The light incident portion 301 is disposed at a position facing the optical system 200, into which image light emitted from the image display element 100 and then collimated by the optical system 200 is incident. The reflection portion 305 is a portion that reflects a beam of image light entering the light guide 300 through the light incident portion 301.

[0081] The light guide unit 302 has a pair of principal planes that are substantially parallel to each other, and is a portion that guides the light beam reflected by the reflection unit 305 by repeating total internal reflection between the pair of principal planes.

[0082] The extraction unit 303 involved in this embodiment is a part that reflects the light beam guided by the light guide unit 302 toward the light emitting unit 304 and extracts it to the outside of the light guide 300. The light emitting unit 304 is a part that emits the light beam reflected by the extraction unit 303 and extracted to the outside of the light guide 300 to the outside of the light guide 300. Due to this configuration, the user of the virtual image display device 1000 can visually recognize the virtual image by viewing the light guide 300 from the light emitting unit 304 side.

[0083] Figure 2 FIG. 1 is an enlarged view of a portion of the light guide 300 including a portion of the extraction unit 303 according to the present embodiment.

[0084] The extraction unit 303 has a plurality of planes 303a substantially parallel to the light emitting unit 304 and a plurality of planes 303b inclined to the light emitting unit 304. The plurality of planes 303a and the plurality of planes 303b are arranged in alternating order in the left-right direction of the drawing (i.e., in the direction from the base end toward the front end of the light guide 300).

[0085] Once the light guided by the light guide unit 302 by repeated total internal reflection reaches each of the plurality of planes 303b, the light is reflected toward the light emitting unit 304 as shown by the light ray R1. Since each of the plurality of planes 303a is arranged between each pair of the plurality of planes 303b, the light can move toward the front end side of the light guide 300 until the light hits one of the plurality of planes 303b. Therefore, the light can be guided by the portion of the light emitting unit 304 arranged on the front end side of the light guide 300. Due to such a configuration, a virtual image display device 1000 capable of wide-angle display can be realized using a thin light guide 300.

[0086] In this embodiment, the light guide body 300 is composed of a pair of light guide members including a first light guide member 310 and a second light guide member 320. Figure 1 As shown, in the light guide 300 involved in this embodiment, the first light guide member 310 is provided with a light incident portion 301, a light guide unit 302, an extraction unit 303, a light emitting unit 304, and a reflection portion 305. In addition, in the light guide 300 involved in this embodiment, the first light guide member 310 and the second light guide member 320 are made of materials having approximately equivalent refractive indices, for example, made of the same material.

[0087] Figure 3 FIG. 1 is an enlarged view of a portion of the light guide body 300 including a portion of the second light guide member 320 according to the present embodiment.

[0088] like Figure 3 As shown, the second light guide member 320 has a pair of end faces 321 at the base end side and the front end side, respectively, and is formed like a parallel plate. In addition, the second light guide member 320 is joined to the light guide unit 302 of the first light guide member 310 via the intermediate layer 400.

[0089] The intermediate layer 400 disposed at a bonding portion between the first light guide member 310 and the second light guide member 320 includes a reflective or transmissive film 401 and an adhesive layer 402 .

[0090] The reflective or transmissive film 401 is formed on the second light guide member 320 by, for example, vapor deposition. The reflective or transmissive film 401 may be, for example, a dielectric film and a metal film made of a silver (Ag) material or the like. The reflective or transmissive film 401 is a coating film having a half-mirror property. The reflective or transmissive film 401 transmits a portion of the light guided by the first light guide member 310 to the second light guide member 320 side, and reflects the remaining portion of the light guided by the first light guide member 310 to the first light guide member 310 side. The half-mirror property of the reflective or transmissive film 401 may be a property of a reflectivity of approximately 50% and a transparency of 50%. However, without limitation thereto, the half-mirror property of the reflective or transmissive film 401 may be, for example, a reflectivity of 30% and a transparency of 70%.

[0091] The adhesive layer 402 is a layer that joins the first light guide member 310 and the second light guide member 320 together, and is made of, for example, an adhesive material. The adhesive layer 402 has, for example, a refractive index that is almost equal to that of the first light guide member 310 and the second light guide member 320 .

[0092] In the light guide 300 according to the present embodiment configured as described above, the second light guide member 320 is formed like a parallel plate and is joined to at least the light guide unit 302 of the first light guide member 310. Due to such a configuration, in the virtual image display device 1000 having the light guide 300, it is possible to suppress a missing error in the brightness of a virtual image to be observed, and to realize a light guide that is easy to manufacture.

[0093] Hereinafter, several advantageous effects of the light guide 300 according to the present embodiment will be described in comparison with the light guide 330 according to the comparative example of the above-mentioned embodiment of the present disclosure.

[0094] Figure 4 FIG. 1 is a schematic diagram of a virtual image display device 1100 having a light guide 330 according to a comparative example of the above-mentioned embodiment of the present disclosure.

[0095] In the virtual image display device 1100 according to the comparative example of the above embodiment of the present disclosure, the light guide 300 of the virtual image display device 1000 is replaced by a light guide 330. The light guide 330 according to the comparative example of the above embodiment includes a light incident portion 301, a light guide unit 302, an extraction unit 303, a light emitting unit 304, and a reflection portion 305. The light guide 330 according to the comparative example of the above embodiment has a shape similar to that of the first light guide member 310 and is made of a material similar to that of the first light guide member 310, but does not include the second light guide member 320.

[0096] Figure 5 FIG. 2 is a diagram showing a light beam guided by a light guide 330 according to the comparative example of the above-mentioned embodiment of the present disclosure.

[0097] like Figure 4 As shown, the light ray R2 is a part of the image light emitted from a part of the image display element 100, and is incident on the plane of the light incident portion 301 at a certain angle. Figure 5 As shown, the light R2 is guided through the light guide unit 302 by repeatedly performing total internal reflection. However, before reaching the front end of the light guide 330, the light R2 contacts the multiple inclined surfaces 303b (see FIG. Figure 2 ) do not collide. Such light R2 does not reach the user's eye E. As a result, there is a lack of picture on the virtual image visually recognized by the user. In other words, a brightness loss error occurs on the virtual image visually recognized by the user. As a result, the image quality of the virtual image deteriorates.

[0098] and Figure 5 Compared to the control shown, Figure 6 FIG. 1 is a diagram showing a light beam guided by the light guide 300 according to the first embodiment of the present disclosure.

[0099] Light R3 is from Figure 1 A portion of the image light emitted from a portion of the image display element 100 is shown, and is Figure 5 The light beam R2 shown in FIG. 1 is incident on the plane of the light incident portion 301 at the same angle. Figure 6 As shown in FIG. 1 , due to the multiple reflections caused by the presence of the second light guide member 320, the light R3 is divided into the light R4, the light R5, the light R6, and the light R7. As a result, the appearance of the light beam of the light R3 and even the entire image light in the light guide 300 can be enlarged. Due to this structure, for example, before the light R6 reaches the front end of the light guide 330, it contacts the multiple inclined surfaces 303b (see FIG. 1 ) inside the extraction unit 303. Figure 2 ) do not collide with any of the light beams. However, the light beams R4 and R5 are reflected by the extraction unit 303, and are emitted to the outside of the light guide 300 through the light emission unit 304, and reach the user's eye E. In other words, there is a high probability that the light beam R3 or even the entire image light will collide with the multiple inclined surfaces 303b inside the extraction unit 303 (see Figure 2 ). For this reason, Figure 5 Compared with the configuration or structure of the comparative example of the first embodiment of the present disclosure, it is possible to prevent the occurrence of a brightness loss error on a virtual image visually recognized by a user, thereby preventing the image quality of the virtual image from being deteriorated.

[0100] In such Figure 6In the configuration and structure shown, there is light such as light R7 that reaches the end face 321 of the second light guide member 320. In order to deal with this situation, the end face 321 can be coated with a material for absorbing light having a wavelength corresponding to the image light, or the end face 321 can be shaped to emit incident light such as light R7 to the outside of the second light guide member 320. Due to this configuration, the reflected light of the light R7 reflected by the end face 321 is prevented from being guided again by the second light guide member 320 or the first light guide member 310. As a result, unnecessary light can be prevented from becoming stray light and contaminating the virtual image, and deterioration of image quality can be prevented from occurring. For example, a material that absorbs visible light can be used for a coating that absorbs light having a wavelength corresponding to the image light. The shape that emits incident light such as light R7 to the outside of the second light guide member 320 is achieved, for example, by roughening and coarsening the end face 321.

[0101] As described above, in the light guide 300 involved in the present embodiment, the second light guide member 320 is formed like a parallel plate and is joined to at least the light guide unit 302 of the first light guide member 310. Due to such a configuration, in the virtual image display device 1000 equipped with the light guide 300, it is possible to suppress the lack error of the brightness of the virtual image to be observed. In addition, the second light guide member 320 formed like a parallel plate as described above can be easily manufactured or prepared independently of the first light guide member 310, and the second light guide member 320 formed like a parallel plate as described above can be easily joined to the first light guide member 310. For this reason, the light guide 300 involved in the present embodiment can be easily manufactured or produced.

[0102] Since the light guide body 300 according to the present embodiment includes the reflective or transmissive film 401 , the introduction or multiple reflection of the image light to the second light guide member 320 can be easily controlled, and the appearance of the light beam can be further expanded.

[0103] In addition, in the light guide body 300 involved in the present embodiment, it is preferred that the first light guide member 310 and the second light guide member 320 are composed of materials having approximately equal refractive indices. If the first light guide member 310 and the second light guide member 320 are composed of materials having approximately equal refractive indices, the angular displacement between the light guided by the first light guide member 310 and the light returned to the first light guide member 310 by reflection after being guided from the first light guide member 310 and introduced into the second light guide member 320 can be effectively controlled. As a result, an ideal virtual image can be displayed. In addition, the refractive indices do not necessarily have to be completely consistent, and there may be some angular displacement between the light guided by the first light guide member 310 and the light returned to the first light guide member 310 by reflection after being guided from the first light guide member 310 and introduced into the second light guide member 320, as long as such displacement does not significantly affect the virtual image to be displayed.

[0104] Furthermore, in the light guide body 300 according to the present embodiment, the first light guide member 310 and the second light guide member 320 are bonded together by the adhesive layer 402 having a refractive index almost equal to that of the first light guide member 310 and the second light guide member 320. Due to this configuration, when light passes through the adhesive layer 402, the change in angle can be controlled, and an ideal virtual image can be displayed.

[0105] In addition, in the light guide 300 according to the present embodiment, since substantially collimated image light is incident on the light incident portion 301, there is a high probability that the image light emitted from the light emitting unit 304 will form an image at one point on the retina of the user's eye. Due to this configuration, even if the optical power of the image light is weak, an ideal virtual image can be displayed.

[0106] Second embodiment

[0107] Figure 7 FIG. 2 is a schematic diagram of a light guide 300 according to a second embodiment of the present disclosure.

[0108] like Figure 1 The light guide 300 in the virtual image display device 1000 shown can be replaced by the light guide 300A involved in the second embodiment of the present disclosure. In the light guide 300A involved in the second embodiment of the present disclosure, the second light guide member 320 and the intermediate layer 400 in the light guide 300 are replaced by the second light guide member 320A and the intermediate layer 400A respectively.

[0109] Figure 8 FIG. 1 is an enlarged view of a portion of the light guide body 300A including a portion of the second light guide member 320A according to the present embodiment.

[0110] like Figure 7 and Figure 8As shown, the second light guide member 320A is shaped like a parallel plate and extends to the front end side of the first light guide member 310. The reflective or transmissive film 401 of the intermediate layer 400A is located at the light guide unit 302 of the first light guide member 310. However, the reflective or transmissive film 401 of the intermediate layer 400A does not extend to the position of the extraction unit 303 or the light emitting unit 304.

[0111] On the contrary, Figure 8 The adhesive layer 402A shown extends to the front end sides of the first light guide member 310 and the second light guide member 320A, and the first light guide member 310 and the second light guide member 320A are adhered together up to the front end.

[0112] As with the light guide 300 involved in the above-mentioned embodiment of the present disclosure, the light guide 300A involved in the present embodiment configured as above can also be easily manufactured, and can suppress the missing error of the brightness of the virtual image to be observed. In the light guide 300A involved in the second embodiment of the present disclosure, when the curvature of the second light guide member 320A is adapted to the curvature of the light emitting unit 304 of the first light guide member 310, the second light guide member 320A and the light emitting unit 304 are joined together. Due to this configuration, the curvature can be reduced, and thus an ideal virtual image with small distortion can be displayed.

[0113] In the light guide 300A according to the second embodiment of the present disclosure, the reflective or transmissive film 401 does not extend to the light emitting unit 304. Due to this configuration, it is possible to prevent the light reflected by the reflective or transmissive film 401 from hitting the extraction unit 303 and causing unwanted light such as stray light. Due to this configuration, it is possible to suppress a decrease in the image quality of a virtual image.

[0114] Fig. 9 FIG. 1 is a partially enlarged view of a light guide according to a modified example of the second embodiment of the present disclosure.

[0115] In the light guide body involved in this variant example of the second embodiment of the present disclosure, the adhesive layer 402 of the intermediate layer 400 does not extend to the front end side of the first light guide member 310 and the second light guide member 320A, and an air region 403 exists between the first light guide member 310 and the second light guide member 320A at the position of the extraction unit 303 and the light emitting unit 304 and at a position closer to the front end side than the extraction unit 303 and the light emitting unit 304.

[0116] Fig.10 FIG. 2 is a diagram showing another configuration or structure of the first light guide member 310 according to the present embodiment.

[0117] Such a first light guide member 310B having a different composition or structure from the first light guide member 310 has a plane 310Ba joined to the second light guide member 320, and the plane 310Ba has a low flatness due to, for example, a manufacturing error or a production error. However, in the present embodiment, the intermediate layer 400B includes a reflective or transmissive film 401 and an adhesive layer 402B, and the adhesive layer 402B has, for example, a refractive index almost equal to that of the first light guide member 310B. Due to this composition, despite the low flatness of the plane 310Ba, the compatibility or integrity of the refractive index between the first light guide member 310B and the second light guide member 320 is maintained, and a virtual image with an ideal image quality can be obtained.

[0118] Fig.11A and Fig. 11B Each of the diagrams shows another configuration or structure of the extraction unit according to the present embodiment.

[0119] More specifically, Fig.11A and Fig. 11B The following are shown respectively: Figure 2 A diagram of another configuration or structure of the extraction unit 303 is shown with plane 303a and plane 303b. Fig. 11B The figure shows the structure or structure of the extraction unit 303A according to the present embodiment, which has a structure or structure different from that of the extraction unit 303. The extraction unit 303a has a plurality of planes 303a substantially parallel to the light emitting unit 304, a plurality of planes 303b inclined to the light emitting unit 304, and a plurality of planes 303c inclined to the light emitting unit 304. The plurality of planes 303b and the plurality of planes 303c are orthogonal to the plurality of planes 303a, and are inclined in mutually different directions with respect to a plane extending in the depth direction of the drawing. The plurality of planes 303a, the plurality of planes 303c, and the plurality of planes 303b are arranged in an alternating order in the left-right direction of the drawing.

[0120] When the extraction unit 303 is used as in the present embodiment, in addition to the light R8 reflected by the plane 303b and traveling toward the light emitting unit 304, there may also be a light R9 reflected by the plane 303a and further reflected by the plane 303b and traveling toward the light emitting unit 304. This light R9 may become stray light for the virtual image to be observed.

[0121] On the contrary, when using Fig. 11BWhen the extraction unit 303a is shown, the light ray R9 does not hit the plane 303b after being reflected by the plane 303a. This is because, due to the existence of the plane 303c, the next plane 303a is configured at a position where no light ray R9 reaches. Therefore, the light ray R9 is less likely to become stray light of the virtual image to be observed, and the deterioration of the image quality of the virtual image can be prevented.

[0122] Third embodiment

[0123] Fig.12 FIG. 2 is a schematic diagram of a light guide 300B according to a third embodiment of the present disclosure.

[0124] like Figure 1 The light guide 300 in the virtual image display device 1000 shown can be replaced by the light guide 300B according to the third embodiment of the present disclosure. In the light guide 300B according to the second embodiment of the present disclosure, the extraction unit 303 of the light guide 300 is replaced by an extraction unit 303B.

[0125] The extraction unit 303B is composed of a large number of reflectors that are arranged in an area inside the first light guide member 310 and coated with a material with a specific reflectivity. Similar to the light guide 300 involved in the above-mentioned embodiment of the present disclosure, the light guide 300B involved in this embodiment constructed as above can also be easily manufactured and can suppress the brightness loss error of the virtual image to be observed.

[0126] Fourth embodiment

[0127] Fig.13 FIG. 4 is a schematic diagram of a light guide 300C according to a fourth embodiment of the present disclosure.

[0128] like Figure 1 The light guide 300 in the virtual image display device 1000 shown in the figure can be replaced by a light guide 300C according to the fourth embodiment of the present disclosure. In the light guide 300C according to the fourth embodiment of the present disclosure, the extraction unit 303 of the light guide 300 is replaced by an extraction unit 303C.

[0129] The extraction unit 303C is provided with a micro-component and a gap area on the plane on the other side of the light emitting unit 304 of the first light guide member 310. Like the light guide 300 involved in the above-mentioned embodiment of the present disclosure, the light guide 300C involved in the present embodiment constructed as above can also be easily manufactured, and can suppress the brightness loss error of the virtual image to be observed.

[0130] Examples and Comparative Examples

[0131] As an embodiment of the present disclosure, the following is given in Figure 1The simulation results of the brightness distribution of the virtual image under the following conditions in the virtual image display device according to the first embodiment of the present disclosure are given below as a comparative example of the above-mentioned embodiment of the present disclosure. Figure 4 The simulation results of the brightness distribution of the virtual image under the following conditions in the virtual image display device are shown. Note that in the above-mentioned comparative example, the second light guide member 320 does not exist, and therefore the conditions are not considered.

[0132] (condition)

[0133] Image display device 100

[0134] Display area: 5.28 mm × 2.97 mm

[0135] Optical system 200

[0136] Viewing angle (vertical angle): 40 degrees

[0137] Focal length: 6.8mm

[0138] F number (FNO.): 5.8

[0139] Second light guide member 320

[0140] Material: Polymethyl methacrylate (PMMA)

[0141] Size:15mm×21mm

[0142] Thickness: 0.7mm

[0143] First light guide member 310

[0144] Material: Polymethyl methacrylate (PMMA)

[0145] Thickness: The thinnest part is 0.5mm, the thickest part is 2.0mm

[0146] Length:59mm

[0147] Width:50mm

[0148] Extraction unit 303

[0149] Width of surface 303b: 0.2mm

[0150] Angle relative to the light emitting unit 304: 27 degrees

[0151] Width of surface 303a: 0.76mm

[0152] Eye box: equal to or wider than 5mm

[0153] Visual clearance: equal to or wider than 15mm

[0154] Fig.14 FIG. 1 is a diagram showing a simulation result of the brightness distribution of a virtual image in a virtual image display device according to a comparative example of the above-mentioned embodiment of the present disclosure.

[0155] Fig.15 1 is a diagram showing simulation results of brightness distribution of a virtual image in the virtual image display device 1000 according to the above embodiment of the present disclosure.

[0156] exist Fig.14 and Fig.15 In the figure, the X direction indicates the long side direction of the light guide ( Figure 1 and Figure 4 The Y direction represents the width direction of the light guide ( Figure 1 and Figure 4 The values ​​in the X and Y directions represent relative positions, with 0 representing the center.

[0157] In such Fig.14 In the control example shown in FIG. 1 , there are significant deficiencies in brightness close to 0 at positions P1, P2, and P3 separated from each other in the X direction. However, according to the above-described embodiments of the present disclosure, in the case of Fig.15 The simulation results shown do not show such a significant lack of brightness close to zero.

[0158] The above embodiments are exemplary and are not limited to the present disclosure. Therefore, in view of the above teachings, many additional modifications and changes can be made. For example, within the scope of the present disclosure, the elements and / or features of different illustrative embodiments can be combined and / or replaced with each other.

[0159] For example, the optical system 200 may be configured to generate substantially collimated light after forming an intermediate image of the image light emitted from the image display element 100. In this configuration, the substantially collimated light is incident on the light guide 300. After the optical system 200 is configured to form the intermediate image in advance, the image display element 100 having a higher weight percentage in the virtual image display device 1000 may be configured on the rear side in a direction away from the light guide 300. Due to this configuration, when the virtual image display device 1000 is configured like glasses, the weight of the front side can be reduced, and a comfortable virtual image display device shaped like glasses, which is also called smart glasses, can be realized.

[0160] In the above-described embodiment of the present disclosure, the light guide is composed of two light guide members such as the first light guide member 310 and the second light guide member 320. However, not limited thereto, in some embodiments, the light guide may be composed of two or more light guide members.

[0161] The second light guide member 320 is bonded to the main plane of the light guide unit 302, which is arranged on the same side of the light emitting unit 304 in the first light guide member 310. However, not limited thereto, the second light guide member 320 may be bonded to the main plane of the light guide unit 302 arranged on the same side of the extraction unit 303.

[0162] The reflective or transmissive film 401 is not limited to that formed on the second light guide member 320 , but may be formed on the first light guide member 310 by means of, for example, vapor deposition.

[0163] In addition, the composition or structure of the light guide or virtual image display device as described above is applicable even when the left and right sides of the attached figure are reversed. The virtual image display device involved in the above-mentioned embodiment of the present disclosure can be configured so that one light guide is observed by both eyes of the user, or can be configured so that a pair of light guides are observed by a pair of eyes respectively. Alternatively, the virtual image display device involved in the above-mentioned embodiment of the present disclosure can be configured small so that one light guide is observed by one eye. Due to the above-mentioned composition and structure, even when a virtual image with a wide angle equal to or greater than, for example, 30 degrees is to be displayed, a light smart eye without brightness missing errors can be realized. The virtual image display device according to the above-mentioned embodiment of the present disclosure can be configured as a head-up display (HUD).

[0164] Hereinafter, embodiments of a light guide body disclosed herein and a virtual image display device including the light guide body will be described with reference to the drawings.

[0165] The light guide body involved in the embodiment of the present disclosure includes a light incident portion for introducing light into the interior of the light guide body, a light guide unit for guiding the light by internal reflection, and a light emitting unit for emitting the light guided by the light guide unit. The light guide unit includes a first reflection surface and a second reflection surface facing each other and substantially parallel to each other. The light introduced into the interior of the light guide unit is guided from the light incident portion side toward the light emitting unit in the light guide unit in a manner that total internal reflection alternately occurs between the first reflection surface and the second reflection surface.

[0166] The second reflective surface is composed of a plurality of image extraction units and a plurality of sub-reflective surfaces which are alternately arranged on the rear side in the light guide direction. The plurality of image extraction units are inclined downward toward the light emitting unit, so that light is extracted to the outside of the light guide body through the light emitting unit. Each sub-reflective surface is formed behind an image extraction unit so as to be roughly parallel to the first reflective surface. The plurality of image extraction units and the plurality of sub-reflective surfaces (33, 133) are alternately arranged.

[0167] There is at least one optical path separation component between the first reflecting surface and the second reflecting surface. The optical path separation component is substantially parallel to the first reflecting surface and the second reflecting surface. The optical path separation component exists in some areas between the first reflecting surface and the second reflecting surface, and the optical path separation component does not exist in other areas between the first reflecting surface and the second reflecting surface. The optical path separation component serves as a boundary surface, totally reflects the light according to the incident angle of the light, and transmits the light when the incident angle of the light is within a predetermined range.

[0168] The light entering the light guide through the light incident portion includes light having a wide reflection angle and light having a narrow reflection angle with respect to the normal of the second reflection surface. Assuming that the wavelength of the light is constant, when the reflection angle of the second reflection surface is wide and the incident angle is wider than the critical angle of the light path separation component, the light path separation component having the above-mentioned boundary surface totally reflects the light. On the other hand, when the reflection angle of the second reflection surface is narrow and the incident angle is narrower than the critical angle of the light path separation component, the light path separation component having the above-mentioned boundary surface allows the light to pass through.

[0169] The optical path separation component can be a single unit or a plurality of units arranged at predetermined intervals in the light guiding direction. In both cases, the optical path separation component is separated from the light incident portion and transmits or totally reflects the light reflected by the second reflection surface according to whether the incident angle is less than or equal to or greater than the critical angle used as a boundary.

[0170] The light reflected by the second reflection surface and passing through the boundary surface of at least one optical path separation component and traveling to the first reflection surface is referred to as the first light. The light reflected by the second reflection surface and then reflected by the boundary surface of at least one optical path separation component and traveling to the second reflection surface is referred to as the second light. In other words, the first light is light in which at least one incident angle with respect to the normal line of the above-mentioned boundary surface has an incident angle narrower than the critical angle of the above-mentioned boundary surface, and the second light is light in which one incident angle with respect to the normal line of the above-mentioned boundary surface has an incident angle equal to or wider than the critical angle.

[0171] There is an area without a boundary surface between the light incident portion and the area including at least one boundary surface, and in such an area without a boundary surface, the second light travels in the light guide body by total internal reflection between the second reflection surface and the boundary surface. By providing the above-mentioned boundary surface, the interval at which the second light of the incident light of each viewing angle that has been substantially collimated is totally reflected by the second reflection surface can be shortened, and the light of each viewing angle can be irradiated to the second reflection surface with uniform light intensity.

[0172] Among the light rays of various viewing angles that are roughly collimated and incident on the light incident portion, the interval at which the first light is totally reflected by the second reflection surface is narrower than the interval at which the second light is totally reflected when there is no boundary surface. Due to this configuration, the second reflection surface can be illuminated by light rays of various viewing angles with uniform light intensity.

[0173] As described above, in a flat light guide body in which a plurality of image extraction units are arranged on the surface on the other side of the surface of the virtual image to be observed, the optical path separation component is arranged between the first reflecting surface and the second reflecting surface. Due to this configuration, light with reduced brightness unevenness and reduced brightness missing errors can be extracted and obtained.

[0174] Fifth embodiment

[0175] Fig.16 FIG. 4 is a schematic diagram of a light guide 3000 according to a fifth embodiment of the present disclosure.

[0176] like Fig.16 As shown, the light guide 3000 involved in the fifth embodiment of the present disclosure is a plate-shaped component made of a transparent material such as glass or plastic. The light guide 3000 can be called a flat light guide plate. The light guide 3000 involved in this embodiment includes a light incident portion 8, a light guide unit 30, and a light emitting unit 40.

[0177] The light incident portion 8 has a wedge-shaped prism 11 on the light incident surface, and a reflector 1 is arranged on the other side of the surface where the prism 11 is arranged. Light is incident on the bottom surface of the prism 11 at a right angle. The prism 11 is a polyhedron made of a transparent material such as glass or crystal. The reflector 1 totally reflects the light passing through the prism 11 and guides it to the light guide unit 30.

[0178] The light guide unit 30 involved in the present embodiment guides the incident light incident from the light incident part 8 to the light emitting unit 40. In addition, the light guide unit 30 involved in the present embodiment has a first reflection surface 2, a second reflection surface 3 and an optical path separation component 4. The first reflection surface 2 reflects the light reflected by the reflector 1 toward the second reflection surface 3. The second reflection surface 3 reflects the light reflected by the first reflection surface 2 toward the first reflection surface 2. The optical path separation component 4 is a film made of a material with a low refractive index such as aluminum fluoride (AlF3) and sodium fluoride (NaF), and the light guide 3000 is formed of a material with a high refractive index such as a plastic material. The optical path separation component 4 is a component that allows light of a first reflection angle θ1 reflected by the second reflection surface 3 to pass through, and reflects light of a second reflection angle θ2 reflected by the second reflection surface 3.

[0179] The second reflecting surface 3 includes a plurality of image extraction units 5 and a plurality of sub-reflecting surfaces 33. The second reflecting surface 3 has a subsequent portion at a specific position in which a plurality of inclined surfaces and a plurality of planes are alternately configured, and such a plurality of inclined surfaces of the second reflecting surface 3 is referred to as image extraction units 5. A plurality of planes of the second reflecting surface 3 after the first inclined surfaces of the plurality of image extraction units 5 are referred to as sub-reflecting surfaces 33.

[0180] The first light wave 6 belongs to a group of light rays with various viewing angles that are incident on the light path separation component 4 at an incident angle that is less than the critical angle of the light path separation component 4. The second light wave 7 belongs to a group of light rays with various viewing angles that are incident on the light path separation component 4 at an incident angle that is equal to or greater than the critical angle of the light path separation component 4.

[0181] The optical path separation component 4 may include a plurality of planes. When the optical path separation component 4 has a plurality of planes, the first light wave 6 and the second light wave 7 are defined for a plurality of light rays that are substantially collimated and incident on the plurality of planes of the optical path separation component 4 at a plurality of viewing angles.

[0182] The first reflection angle θ1 is an angle at which the first light wave 6 is reflected with respect to the normal line of the second reflection surface 3. The second reflection angle θ2 is an angle at which the second light wave 7 is reflected with respect to the normal line of the second reflection surface 3.

[0183] In this embodiment, the three-axis directions including the X direction, the Y direction and the Z direction are consistent with the above-mentioned Fig.40 Regarding the Y-axis direction, when viewed from the position of the eye, the direction toward the light emitting unit 40 is called the normal (positive) direction, and the direction from the front side toward the position of the eye is called the negative direction.

[0184] About the Z-axis direction, the light guiding direction, that is, Fig.16 The direction shown traveling from left to right is called the normal (positive) direction.

[0185] like Fig.16 As shown, the light reflected by the plurality of image extraction units 5 is emitted from the light emitting unit 40 of the first reflection surface 2 in the negative direction of the Y axis. The light emitting unit 40 has a plurality of image extraction parts 5 and a plurality of sub-reflection surfaces 33. Each of the plurality of image extraction units 5 undergoes, for example, aluminum vapor deposition and dielectric multilayer vapor deposition, and serves as a reflector. The plurality of image extraction units 5 are arranged at a plurality of positions, and divide the second reflection surface 3 into a plurality of segments or regions. Each of the plurality of image extraction units 5 connects the second reflection surface 3 to one of the sub-reflection surfaces 33, and connects each pair of sub-reflection surfaces 33. Each of the plurality of image extraction units 5 is inclined at an obtuse angle relative to the second reflection surface 3.

[0186] The plurality of image capturing units 5 and the second reflecting surface 3 inclined at an obtuse angle constitute a part of the plurality of sub-reflecting surfaces 33. The plurality of image capturing units 5 and the plurality of sub-reflecting surfaces 33 are alternately connected to each other, and the size of the space between the plurality of sub-reflecting surfaces 33 and the first reflecting surface 2 is in the light guiding direction (i.e., Fig.16 The positive Z direction in the image becomes narrower.

[0187] In this embodiment, substantially collimated light is emitted toward the light guide 3000. Light corresponding to the pixel at the center of the image is incident on the bottom surface of the prism 11 at a right angle and enters the light guide 3000, which is a flat light guide plate. The incident light is reflected by the reflector 1 integrated with the light guide 3000 and travels toward the first reflection surface 2. The first reflection surface 2 totally reflects the light at the same angle as the incident angle.

[0188] The light with each wavelength totally reflected by the first reflection surface 2 is emitted toward the second reflection surface 3. Then, the light with each wavelength substantially collimated travels toward the light emitting unit 40 through the light guide 3000 in a manner of repeated incidence and reflection between the first reflection surface 2 and the second reflection surface 3. The first reflection surface 2 and the second reflection surface 3 are substantially parallel to each other, and the amount of misalignment relative to the parallelism needs to be equal to or less than ±1°.

[0189] In this embodiment, the optical path separation component 4 is arranged between the first reflection surface 2 and the second reflection surface 3. The optical path separation component 4 completely reflects or transmits light according to whether the incident angle is greater than or narrower than a predetermined critical angle. In other words, the optical path separation component 4 totally reflects light whose incident angle is larger than the critical angle, and transmits light whose incident angle is smaller than the critical angle.

[0190] In the present embodiment, the first light wave 6 and the second light wave 7 are defined as follows. In the following description, a light wave that travels toward the first reflection surface 2 from a position where the light is first totally reflected by the second reflection surface 3 and then totally reflected by the light path separation component 4 and then travels toward the second reflection surface 3 is referred to as the second light wave 7. In the following description, a light wave that is first totally reflected by the second reflection surface 3 and then passes through the light path separation component 4 and then travels toward the first reflection surface 2 is referred to as the first light wave 6. The second light wave 7 is guided between the second reflection surface 3 and the light path separation component 4 in a manner that repeatedly performs total internal reflection, and the first light wave 6 is guided between the first reflection surface 2 and the second reflection surface 3 in a manner that repeatedly performs total internal reflection.

[0191] As described above, the first light wave 6 does not satisfy the condition of total reflection and therefore passes through the optical path separation component 4. On the contrary, since the second light wave 7 satisfies the condition of total reflection, it is totally reflected by the optical path separation component 4. The first light wave 6 and the second light wave 7 guided by the light guide 3000 are irradiated onto the plurality of image extraction units 5. Then, the first light wave 6 and the second light wave 7 are reflected at an angle different from the total reflection angle of the first reflection surface 2 and the second reflection surface 3, and are emitted to the outside of the light guide 3000 through the light emission unit 40. By observing the emitted light with the eyes, the image formed by the image forming element can be observed.

[0192] In the light guide 3000 involved in the above-mentioned embodiment of the present disclosure, an optical path separation component 4 is provided between the first reflection surface 2 and the second reflection surface 3, and the optical path separation component 4 separates the incident light into totally reflected light and transmitted light according to the reflection angle of the light of the second reflection surface 3. According to the light guide having the above-mentioned structure involved in the above-mentioned embodiment of the present disclosure, light with reduced brightness unevenness and reduced brightness missing errors can be taken out and obtained.

[0193] Fig.17 The diagram is divided into several functional areas according to the present embodiment. Fig.16 Schematic diagram of a light guide 3000.

[0194] like Fig.17 As shown, the light incident portion 8 is a functional area that converts the light that is roughly collimated and incident on the planar light guide plate into light having an angle suitable for being guided by the light guide body 3000. The non-light path separation area 9 is a functional area where at least one light path separation component 4 does not exist between the first reflection surface 2 and the second reflection surface 3. In this embodiment, as Fig.16 As shown, there is an optical path separation component 4, and there is a pair of non-optical path separation areas 9 on the left and right sides of the optical path separation component 4.

[0195] The non-optical path separation area 9 existing between the light incident portion 8 and the optical path separation area 10 is a functional area for irradiating the light that is totally reflected for the first time by the first reflection surface 2 to the area of ​​the first total reflection of the second reflection surface 3. When there is no pair of non-optical path separation areas 9, the second light wave 7 is totally reflected by the first reflection surface 2 for the first time, and then totally reflected by the optical path separation component 4, and is guided and advanced by repeated total reflection between the first reflection surface 2 and the optical path separation component 4. However, there is a problem that the multiple image extraction units 5 that should be irradiated with light are not irradiated by the second light wave 7, and light cannot be extracted at the desired position.

[0196] For example, the above-mentioned problem can be solved by dividing the first reflecting surface 2 into several intervals and configuring a diffraction grating as one of the image extraction units 5 between each pair of divided intervals of the first reflecting surface 2. However, the diffraction angle of each diffraction grating is different according to the wavelength. For this reason, there are problems such as that the wavelength of the transmitted light may be dispersed, or color irregularities or spots may appear on the virtual image. In the above-mentioned embodiment of the present disclosure, by dividing the second reflecting surface 3 into several intervals and configuring a reflector as one of the image extraction units 5 between each pair of divided intervals of the second reflecting surface 3 to extract light, problems such as that the wavelength of the transmitted light may be dispersed or color irregularities or spots may appear on the virtual image are solved.

[0197] The optical path separation area 10 includes at least one boundary surface between the first reflection surface 2 and the second reflection surface 3. The optical path separation area 10 guides light having a wider total reflection angle, such as the second light wave 7, by repeatedly performing total reflection between the second reflection surface 3 and the optical path separation member 4. Due to this configuration, the interval of the total internal reflection performed is shortened, and the area of ​​the second reflection surface 3 that is not irradiated by any light wave is reduced. As a result, desired light can be taken out and obtained from the plurality of image extraction units 5.

[0198] In the non-optical path separation region 9 adjacent to the optical path separation region 10 in the positive direction of the Z axis, light having a narrow total reflection angle such as the first light wave 6 is taken out from the plurality of image extraction units 5. For this reason, the optical path separation member 4 does not require a boundary surface.

[0199] Fig.38 1 is a diagram showing a state in which the first light wave 6 and the second light wave 7 according to the present embodiment reach the eye box 15 in the light guide 3000 .

[0200] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted. Fig.38 As shown, in this embodiment, both the first light wave 6 and the second light wave 7 reach the eye box 15 .

[0201] Fig.18 The fifth embodiment of the present disclosure is shown in FIG. Fig.39 The conditions in the comparative example shown are diagrams showing how light is guided by the light guide 3000 when light is incident on the light guide 3000 under the same conditions.

[0202] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted. Fig.18 As shown, substantially uniform light can be extracted and obtained from the plurality of image extraction units 5 in the region where the optical path separation member 4 disposed between the first reflecting surface 2 and the second reflecting surface 3 exists.

[0203] Fig.19 The diagram shows that light such as the first light wave 6 is incident on the light guide 3000 at a relatively small reflection angle and then is transmitted and guided within the light guide 3000 at a relatively small total reflection angle.

[0204] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted.

[0205] Fig.19 The first light wave 6 shown in FIG. 4 does not satisfy the condition of total reflection when it hits the light path separation component 4. Fig.19 The first light wave 6 shown passes through the boundary surface of the optical path separation component 4 and is guided by the first reflection surface 2 and the second reflection surface 3 in a manner of repeated total internal reflection. The first light wave 6 has a small total reflection angle and is therefore totally reflected at narrow intervals by the second reflection surface 3. Due to this configuration, almost the entire area of ​​the second reflection surface 3 is illuminated by light of each viewing angle that is approximately collimated, and some light is taken out to the outside of the light guide 3000 through all of the multiple image extraction units 5.

[0206] Modifications

[0207] Fig. 20 FIG. 4 is a diagram of a light guide 4000 according to a modified example of the above-described embodiment of the present disclosure.

[0208] In this variation of the above-mentioned embodiment of the present disclosure, the size of each space between the second reflecting surface 3 and the first reflecting surface 2 divided into a plurality of sections or regions remains unchanged. In other words, the size of the space between the second reflecting surface 3 and the first reflecting surface 2 does not narrow as the position in the Z direction, which is the light guiding direction, shifts.

[0209] also, Fig. 20 It shows how light waves like the second light wave 7 are guided through the light guide 4000 at a wider total reflection angle.

[0210] In addition, in Fig. 20 In the configuration or structure of the modified example of the fifth embodiment of the present disclosure shown in the figure, at least one optical path separation component 4 is arranged between the first reflection surface 2 and the second reflection surface 3, and is separated from the light incident part. In addition to the multiple image extraction units 5 and the multiple sub-reflection surfaces provided for these image extraction units 5, since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure Fig.16 , so the description of each element or component of the light guide 3000 is omitted.

[0211] like Fig. 20 As shown, the light wave emitted toward one of the plurality of image extraction units 5 is reflected by the plurality of image extraction units 5, and is emitted through the optical path separation part 4 and is taken out to the outside of the light guide 3000. However, the light intensity of the light reaching the image extraction unit 5 may decrease as the light travels to the tail end of the plurality of image extraction units 5 arranged along the traveling direction of the light, and no light may be taken out through some of the plurality of image extraction units 5.

[0212] In view of this, as in the configuration or structure involved in the fifth embodiment of the present disclosure, if the size of the space between the second reflection surface 3 and the first reflection surface 2 divided into a plurality of sections or regions is gradually reduced in the light guiding direction (i.e., the Z direction), the gap between a pair of light beams to be taken out can be eliminated, or at least the gap between a pair of light beams to be taken out can be reduced. Fig. 20 In a variation of the fifth embodiment of the present disclosure in which the size of the space between the second reflecting surface 3 and the first reflecting surface 2 is not changed, if the optical path separation component 4 is arranged between the first reflecting surface 2 and the second reflecting surface 3, at least the gap between a pair of light beams to be taken out can be reduced.

[0213] Fig.21 , Fig. 22 and Fig.23 Fig.23 Shown respectively are diagrams of how light passes through the lens 12 of the user's eye to reach the retina 14 and forms an image in the light guide 3000 when the second light wave 7 is transmitted at a wider second reflection angle θ2 and is taken out to the outside of the light guide 3000 through multiple image extraction units 5 according to the fifth embodiment of the present disclosure.

[0214] Fig.21 1 and 2 are diagrams showing a state at the center of the eye box 15 according to the present embodiment.

[0215] Fig. 22 The diagram shows a state at the left edge of the eye box 15 according to the present embodiment.

[0216] Fig.23 The diagram shows a state at the right edge of the eye box 15 according to the present embodiment.

[0217] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted. Fig.21 , Fig. 22 , Fig.23 In the illustrated embodiment, regardless of the position of the eye within the eye box 15 , uniform light can be extracted from the plurality of image extraction units 5 , and an image can be formed on the retina 14 based on the uniform light.

[0218] Fig.24 , Fig.25 and Fig.26Shown respectively are diagrams of how light passes through the lens 12 of the user's eye to reach the retina 14 and forms an image in the light guide 3000 when the first light wave 6 is transmitted at a narrower first reflection angle θ1 and is taken out to the outside of the light guide 3000 through multiple image extraction units 5 according to the fifth embodiment of the present disclosure.

[0219] Fig.24 1 and 2 are diagrams showing a state at the center of the eye box 15 according to the present embodiment.

[0220] Fig.25 The diagram shows a state at the left edge of the eye box 15 according to the present embodiment.

[0221] Fig.26 The diagram shows a state at the right edge of the eye box 15 according to the present embodiment.

[0222] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted. Fig.24 , Fig.25 and Fig.26 In the illustrated embodiment, regardless of the position of the eye within the eye box 15 , uniform light can be extracted from the plurality of image extraction units 5 , and an image can be formed on the retina 14 based on the uniform light.

[0223] From About Figure 21 to Figure 26 As can be seen from the above description, at least one optical path separation member 4 is provided between the first reflection surface 2 and half or more of the plurality of image capturing units 5. Due to this configuration, the width of the eye box 15 can be increased to a sufficient size.

[0224] The light guided at a wider total reflection angle in the light guide 3000 is emitted toward the eye box 15 as light taken out and emitted from one of the plurality of image extraction units 5 on the side of the light incident portion 8. Conversely, the light guided at the first reflection angle θ1 in the light guide 3000 is emitted toward the eye box 15 as light taken out and emitted from one of the plurality of image extraction units 5 on the opposite side of the light incident portion 8. In an augmented reality (AR) display, as a result of eye movement, the retina 14 must be illuminated by light having all viewing angles regardless of the position of the eye in the eye box 15. For this reason, it is beneficial to increase the width of the eye box 15.

[0225] from Fig.24It can be seen that the light guided in the light guide 3000 at a narrower total reflection angle is guided through the space between the first reflection surface 2 and the second reflection surface 3 in a manner of repeated total internal reflection. Due to this structure, missing errors will not occur. In order to achieve this function, at least one optical path separation component 4 is arranged between the first reflection surface 2 and a plurality of image extraction units 5 that is equal to or greater than half. Due to this structure, even if the eye is located at a position farther from the center of the area where the plurality of image extraction units 5 exist relative to the light incident portion 8, the light guided in the light guide 3000 at a wider total reflection angle can be observed, and the area where the light can be observed becomes larger.

[0226] Fig. 27 Shown is a conditional diagram of a state in which the second light wave 7 is irradiated onto almost the entire area of ​​the second reflection surface 3 when the second light wave 7 is guided between the second reflection surface 3 and the optical path separation component 4 in a manner of repeatedly performing total reflection at a second reflection angle θ2 according to the fifth embodiment of the present disclosure.

[0227] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 Therefore, description of each element or component of the light guide 3000 is omitted. In the following description, the area or part that is not irradiated by the light wave 7 is referred to as a missing error.

[0228] When the relations in the following two equations hold true, the missing error portion 16 disappears.

[0229] W2 / sin(θ2)=d

[0230] W2'≥W2×2

[0231] In the above formula, W2 represents the second light wave 7 (for example, referring to Fig.21 ), the region 28 is closer to the rear side of the light guiding direction than the boundary 21 between the light path separation region 10 and the non-light path separation region 9 closest to the light incident portion 8, and d represents the distance between the second reflecting surface 3 and the light path separation component 4. In addition, W2' represents the second beam width of the second light wave 7 emitted to the second reflecting surface 3 for the first time.

[0232] like Fig.28 As shown, Fig. 27 Compared with the configuration example shown in FIG. 1 , even if the optical path separation component 4 is located closer to the second reflection surface 3, as long as the above conditions are met, no missing error will occur. Fig.16 , so the description of each element or component of the light guide 3000 is omitted.

[0233] Fig.29 , Fig.30 and Fig.31 The diagram shows the conditions for the occurrence of a deletion error as described above according to the present embodiment.

[0234] When the relationship in the following two equations does not hold, a missing error portion 16 occurs.

[0235] W2 / sin(θ2)=d

[0236] W2'≥W2×2

[0237] In the above formula, W2 represents the second light wave 7 (for example, referring to Fig.21 ), the region 28 is closer to the rear side of the light guiding direction than the boundary 21 between the light path separation region 10 and the non-light path separation region 9 closest to the light incident portion 8, and W2' represents the second beam width of the second light wave 7 that is first emitted to the second reflecting surface 3. In addition, d represents the distance between the second reflecting surface 3 and the light path separation component 4.

[0238] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted.

[0239] In such Fig.29 In the conditions shown, the conditions about W2, W2' and θ2 are equivalent to Fig. 27 However, in Fig.29 The distance d between the second reflecting surface 3 and the optical path separation component 4 under the conditions shown is Fig. 27 The conditions shown are longer. Therefore, Fig. 27 In the same manner as in the configuration example shown, the following relationship holds.

[0240] W2'≥W2×2

[0241] However, the following equation holds true, and one of the above equations does not hold true.

[0242] W2 / sin(θ2) <d

[0243] Therefore, a missing error portion 16 is generated at a position where the light wave 7 is not irradiated to the second reflecting surface 3 .

[0244] In such Fig.30 In the conditions shown, the conditions regarding W2, θ2 and d are equivalent to those Fig. 27 However, Fig. 27 Compared with the conditions shown, Fig.30The boundary 21 under the conditions shown is located closer to the light incident portion. Therefore, a portion of the light beam that is first totally reflected by the first reflection surface 2 and then moves toward the second reflection surface 3 in the light guiding direction is totally reflected by the light path separation component 4, and the second light beam width W2' is greater than the above-mentioned Fig. 27 The conditions described are narrow. Therefore, the relationship in the following equation is satisfied.

[0245] W2 / sin(θ2)=d

[0246] However, the following equation holds true, and one of the above equations does not hold true.

[0247] W2' <W2×2

[0248] Therefore, a missing error portion 16 occurs on the second reflecting surface 3 .

[0249] In such Fig.31 In the conditions shown, the conditions regarding W2', θ2 and d are equivalent to those Fig. 27 However, Fig. 27 Compared with the conditions shown, Fig.31 The boundary 21 under the conditions shown is located further away from the light incident portion. Fig. 27 The conditions described are narrow. Therefore, the relationship in the following equation is satisfied.

[0250] W2'≥W2×2

[0251] However, the following equation holds true, and one of the above equations does not hold true.

[0252] W2 / sin(θ2) <d

[0253] Therefore, a missing error portion 16 occurs on the second reflecting surface 3 .

[0254] like Fig.29 , Fig.30 , Fig.31 In the configuration example shown, when a missing error portion 16 occurs and one of the image extraction units 5 is located at the position of the missing error portion 16, light cannot be extracted through the image extraction unit 5, and brightness unevenness or brightness missing errors will appear on the virtual image to be observed.

[0255] Design conditions are required to prevent the missing error portion 16.

[0256] Fig.32 and Fig.33 These are condition diagrams for causing no missing error on the second reflection surface 3 in the light guide 3000 according to the present embodiment in the first light wave 6 guided by repeatedly being totally reflected at the first reflection angle θ1 between the first reflection surface 2 and the second reflection surface 3 .

[0257] Since the configuration or structure of these drawings is equivalent to that of the fifth embodiment of the present disclosure, Fig.16 , so the description of each element or component of the light guide 3000 is omitted.

[0258] Fig.32 and Fig.33 These are diagrams showing that according to the present embodiment, all the light of the first light wave 6 does not satisfy the condition of being totally reflected by the light path separation member 4 and passes through the light path separation member 4 .

[0259] When the conditions in the equation given below are satisfied, the deletion error portion 16 caused by the first light wave 6 disappears.

[0260] W1 / (2×sin(θ1))=D

[0261] In the above formula, W1 represents the third beam width of the first light wave 6 emitted to the area of ​​the second reflection surface 3 that completely reflects the incident light for the first time. In addition, D represents the distance between the first reflection surface 2 and the second reflection surface 3 at the area of ​​the second reflection surface 3 that completely reflects the incident light for the first time.

[0262] In order to eliminate the possibility of brightness omission error or brightness non-uniformity caused by the first light wave 6 under the above conditions, the above conditions need to be satisfied.

[0263] Fig.34 The figure shows a state diagram of a missing error portion 16 caused by light not satisfying the total reflection condition according to a comparative example of the above-mentioned embodiment of the present disclosure.

[0264] In addition, the light guide 3000 can also be configured to satisfy the above-mentioned condition of the reflective surface that does not generate missing errors. In this way, in both the case of the narrower reflection angle θ1 and the wider reflection angle θ2, the possibility of missing errors or uneven brightness on the image to be visually recognized can be reduced. Since both the light with a wider reflection angle and the light with a narrower reflection angle can be guided by the first reflection surface 102 and the second reflection surface 103, the field of view of the image can be increased, and the visual angle of the virtual image to be observed can be widened.

[0265] Sixth Embodiment

[0266] Fig.35 and Fig.36 Each of the drawings shows a part of a light guide 3000 in which the optical path separation member 4 according to the sixth embodiment of the present disclosure has two layers.

[0267] The components of the light guide 3000 are identical to those of the light guide 3000 except for the light path separation member 4. Fig.16The fifth embodiment of the present disclosure is shown in FIG. 1 , and therefore, detailed description thereof is omitted. Fig.35 and Fig.36 As shown, the optical path separation component is divided into two layers, including an optical path separation component 4 close to the first reflecting surface 2 and an optical path separation component 4 close to the second reflecting surface 3, and the two layers are configured to overlap each other and thus be parallel to each other with a certain spacing space therebetween.

[0268] like Fig.35 As shown, the second light wave 7 is totally reflected at a second reflection angle θ2 by one of the light path separation components 4, which is closer to the second reflection surface 3 than the other light path separation component 4. Fig.36 As shown, a light wave having a total reflection angle narrower than the second light wave 7 and wider than the first light wave 6 passes through one of the optical path separation components 4 close to the second reflection surface 3, and is totally reflected by one of the optical path separation components 4 close to the first reflection surface 2 when the total reflection condition is met.

[0269] As described above, in the present embodiment, the optical path separation component 4 is provided as a multilayer. Due to this configuration, the missing error portion 16 can be eliminated while maintaining a wide beam width for each viewing angle. In order to provide an optical path separation component 4 using a multilayer, the critical angle of an optical path separation component 4 that is closer to the first reflecting surface 2 than another optical path separation component is reduced to a value smaller than that of the other optical path separation component. The critical angle is determined based on the relationship between the refractive index of the optical path separation component 4 and the refractive index of the light guide unit 30. To this end, the refractive index of the optical path separation component can be reduced according to the relative position of the first reflecting surface 2 and each layer of the plurality of optical path separation components 4, thereby configuring the plurality of optical path separation components 4. The conditions for such a plurality of optical path separation components are described in detail below.

[0270] Assuming that the optical path separation component 4 is composed of i thin film layers, the relationship in the following formula needs to be satisfied.

[0271] d(m) <d(m-p)<D

[0272] In the above formula, d(m) represents the distance between the second reflection surface 3 and the m-th optical path separation component 4 from the first reflection surface 2, and D represents the distance between the first reflection surface 2 and the second reflection surface 3. In addition, p represents any desired natural number equal to or greater than 1 and less than i.

[0273] In addition, the relationship in the following formula needs to be satisfied.

[0274] n(mp) <n(m)<N

[0275] In the above formula, n(m) represents the refractive index of the m-th optical path separation member 4 . In addition, N represents the refractive index of the light guide unit 30 .

[0276] Note also that i represents a natural number equal to or greater than 2, and m represents a natural number equal to or greater than 2 but equal to or less than i. Furthermore, p represents a natural number equal to or greater than 1 but less than m.

[0277] Fig.37 1 and 2. The sixth embodiment of the present disclosure shows a situation in which light rays having various viewing angles are repeatedly and dispersedly transmitted in order to display a virtual image at a short distance.

[0278] like Fig.37 As shown, when the light wave reflected by the second reflection surface 3 at the second reflection angle θ2 and the light wave reflected by the second reflection surface 3 at the total reflection angle θ2+Δθ exist in a mixed manner, some areas of the second reflection surface 3 are illuminated by two or more light waves in an overlapping manner, and the illumination intensity is increased at these areas of the second reflection surface 3. When the image is formed by completely collimated parallel light and the intensity of this collimated parallel light is uniform, the intensity of the light irradiated to the second reflection surface 3 is uniform. Fig.37 In the figure, reference numeral 25 indicates an area where a light beam overlaps with a different light beam, and reference numeral 26 indicates a light beam having a reflection angle of θ2 on the second reflection surface 3. In addition, reference numeral 27 indicates a light beam having a reflection angle of θ2+Δθ on the second reflection surface 3. The configuration or structure of the light guide body involved in this embodiment is equivalent to that of Fig.16 The configuration or structure related to the fifth embodiment of the present disclosure is shown, and therefore its detailed description is omitted.

[0279] As described above, the virtual image display device can be configured using the light guide 3000 involved in the above embodiment of the present disclosure.

[0280] like Fig.40 As shown, the virtual image display device includes an image display device 50 that outputs image light of a displayed image, a collimating optical system 51 that collimates the light emitted by the image display device 50 and emits the collimated light, and a light guide 3000 as a virtual image display optical system involved in the above-mentioned embodiment of the present disclosure.

[0281] The image display device 50 is a device that outputs image light that forms a display image of a virtual image projected and displayed by the light guide 3000. Preferably, an organic light emitting diode (OLED) or a liquid crystal display (LCD) is used for the image display device 50. However, it is not limited thereto, and various other display elements may be used for the image display device 50. For example, a digital micromirror device (DMD) may be used as the image display device 50. Alternatively, a thin film transistor (TFT) or a liquid crystal on silicon (LCoS) may be used as the image display device 50. In addition, a microelectromechanical system (MEMS) may be used as the image display device 50.

[0282] In such Fig.40 In the illustrated embodiment, a case is described in which, for example, liquid crystal on silicon (LCoS) and a digital micromirror device (DMD) that require a light source are used for the image display device 50, and a light source 52 that emits illumination light to illuminate the image display surface of the image display device 50 with light is added. The light source 52 can use various elements or devices, for example, a light emitting diode (LED), a semiconductor laser, a laser diode (LD), or a discharge lamp can be used as the light source 52.

[0283] The collimating optical system 51 is constituted by, for example, a plurality of optical lenses or apertures, and amplifies the light output from the image display device 50 to emit collimated light.

[0284] According to this virtual image display device, light formed by the image display device 50, such as emitted from the light source 52, is magnified by the collimating optical system 51 and incident on the light guide 3000. In other words, the light magnified by the collimating optical system 51 is incident on the light incident portion 8 of the light guide 3000, and is reflected by the reflector 1 and guided to the inside of the light guide 3000. In the configuration involved in the fifth embodiment of the present application as described above, the light is further guided to the light emitting unit 40. Then, the guided light is emitted from the light emitting unit 40 to the user's eyes as image data. Due to this configuration, the user of the virtual image display device can visually recognize the virtual image by observing the line of sight in front of the light guide 3000 through the light emitting unit 40 of the light guide 3000.

[0285] In the above Figures 16 to 40 In the embodiment of the present disclosure described above, the case is described in which the light incident portion 8 of the light guide 3000 is arranged on the left side of the observer observing the virtual image and light is incident on the light guide 3000 from the left side of the observer observing the virtual image. Even if the configuration or structure as described above is reversed in the left-right direction, that is, even if the light incident portion 8 of the light guide 3000 is arranged on the right side of the observer observing the virtual image and light is incident on the light guide 3000 from the right side of the observer observing the virtual image, similar beneficial effects as those of the above-described embodiment of the present disclosure can be achieved.

[0286] Fig.41A , Fig.41B and Fig.41C These are diagrams showing a case where the light guide 3000 according to the fifth embodiment of the present disclosure is used in a virtual image display device configured as a glasses-like type, that is, a head mounted display (HMD) according to an embodiment of the present disclosure.

[0287] More specifically, Fig.41AThe figure shows a case where a single light guide 3000 is used for a binocular head mounted display (HMD), and the optical entrance 8 of the light guide 3000 is arranged on the right side of the user who is an observer observing a virtual image. The light guide 3000 involved in this embodiment is fixed to a pair of frames 410 used as side pieces of glasses hung on the ears of the user. Fig.41A , Fig.41B and Fig.41C , a pair of frames 410 are shown in a simplified manner. However, this is not limited thereto, and the pair of frames 410 need not always be arranged on both sides of the light guide 3000. The pair of frames 400 may be formed as a single unit to cover the edge of the upper side or the bottom side of the light guide 3000.

[0288] On the contrary, Fig.41B and Fig.41C 1 and 2 are diagrams showing an embodiment of miniaturizing a light guide 3000 and using it for a single-eye head mounted display (HMD). More specifically, Fig.41B The case shown is that a pair of light guide bodies 3000 are arranged to fit both the right eye and the left eye of the user, and the light incident portion 8 of each of the light guide bodies 3000 is arranged at the outer portion of both the right and left sides.

[0289] exist Fig.41A , Fig.41B and Fig.41C , the illustration of the virtual image optical system or the light source is omitted. However, such elements can be mounted on a pair of frames 400. In other words, in the case of Fig.41A and Fig.41C In the illustrated embodiment, the light source 52, the image display device 50, and the collimating optical system 51 may be mounted on the right eye side of one of the pair of frames 410. Fig.41B In the illustrated embodiment, the light source 52, the image display device 50, and the collimating optical system 51 may be mounted to a pair of frames 400 on the left and right sides.

[0290] In such Fig.41A , Fig.41B , Fig.41C In the illustrated embodiment, the light guide 3000 involved in the fifth embodiment of the present disclosure is used for a case where the light guide 3000 is configured as a glasses-type HMD as described above. In addition, the light guide 4000 involved in the above-mentioned variation of the fifth embodiment of the present disclosure can also be used for an HMD configured as a glasses-type. The light guide 3000 involved in the above-mentioned embodiment of the present disclosure can also be used for other types of HMDs, and can also be used for a head-up display (HUD). In particular, the light guide 3000 involved in the above-mentioned embodiment of the present disclosure is suitable for displaying a virtual image of the original image formed by a light beam optically modulated by a tiny device.

[0291] As described above, the light guide 3000 involved in the embodiment of the present disclosure can be fitted to the human face like glasses. If the light emitted from, for example, the image display element is collimated and incident on the light incident portion 8, then, as described above, the image formed by, for example, the image display element can be observed as a virtual image. Since the light guide 3000 involved in the above embodiment of the present disclosure has a transparent body, the scene around the image can be observed together with the image.

[0292] In view of the above teachings, various additional modifications and variations are possible. It should therefore be understood that, within the scope of the appended claims, the disclosure of the present invention may be implemented in a manner different from that specifically described herein. For example, within the scope of the present disclosure and the appended claims, elements and / or features of different illustrative embodiments may be combined with each other and / or replaced with each other. For example, some elements described in the above embodiments may be extracted. In addition, the elements involved in each embodiment or variation may be appropriately combined.

[0293] This patent application is based upon and claims the benefit of priority from Japanese Patent Application Nos. 2020-007085 and 2020-050321 filed on January 20, 2020 and March 19, 2020, respectively, with the Japan Patent Office, the disclosures of which are incorporated herein by reference in their entirety.

[0294] Reference numerals list

[0295] 100 Image display components

[0296] 200 Optical System

[0297] 300 Light guide

[0298] 8, 108, 301 Light incident part

[0299] 30, 130, 302 light guide unit

[0300] 303 Extraction Unit

[0301] 40, 140, 304 Light emission unit

[0302] 310 first light guide member

[0303] 320 second light guide member

[0304] 321 End face

[0305] 401 Reflective or transmissive film

[0306] 402 Adhesive layer

[0307] 1000 Virtual Image Display Device

[0308] 1 Reflector

[0309] 2.102 First reflection surface

[0310] 3.103 Second reflection surface

[0311] 4 Optical path separation components

[0312] 5 Image extraction unit

[0313] 6 The First Light Wave

[0314] 7 The Second Light Wave

[0315] 8 Light incident part

[0316] 9 Non-optical path separation area

[0317] 10 Optical path separation area

[0318] 11 Prism

[0319] 12 Lens

[0320] 14 Retina

[0321] 15 Eye Box

[0322] 16 Missing Error

[0323] 21 Boundary

[0324] 25 Area where a beam overlaps with another beam

[0325] 26 The light beam with a reflection angle of θ2 on the second reflection surface 3

[0326] 27 The light beam with a reflection angle of θ2+Δθ on the second reflection surface 3

[0327] 28 The area of ​​the first total reflection of light by the second reflection surface 3

[0328] 30 Light guide unit

[0329] 33, 133 sub-reflector

[0330] 40 Light emission unit

[0331] 50 Image display device

[0332] 51 Collimation optical system

[0333] 52 Light Source

[0334] 3000 Light Guide

[0335] 4000 Light Guide

[0336] 410 Frame

[0337] θ1 First reflection angle

[0338] θ2 Second reflection angle

[0339] W2 First beam width

[0340] W2' Second beam width

[0341] W1 Third beam width

[0342] d Distance

[0343] D Distance

[0344] 101 Light Source

Claims

1. A light guide, comprising: a light guide member configured to guide and emit light; a light incident portion having a surface for incident light; a light guiding unit configured to guide the light incident on the light incident portion by repeated reflection; a light emitting unit configured to emit the light to the outside of the light guide, and an extraction unit configured to reflect the light guided by the light guide unit toward the light emitting unit, Wherein, the light guiding unit comprises: a first reflecting surface and a second reflecting surface facing each other and parallel to each other, and at least one optical path separation component is disposed between the first reflecting surface and the second reflecting surface, wherein the optical path separation component is separated from the light incident portion, Wherein, the optical path separation component includes i layers of thin films arranged to overlap and be parallel to each other, wherein the i layers of thin films are separated from each other, Among them, the following formula is satisfied d(m) <d(m-p)<D Here, d(m) represents the distance between the second reflecting surface and the mth thin film among the i-th thin films of the optical path separation member relative to the first reflecting surface. D represents the distance between the first reflecting surface and the second reflecting surface, p represents any natural number equal to or greater than 1 and less than i, and Among them, the following equation is satisfied: n(mp) <n(m)<N Here, n(m) represents the refractive index of the mth thin film among the i-th thin films of the optical path separation component, N represents the refractive index of the light guiding unit, i represents a natural number equal to or greater than 2, m represents a natural number equal to or greater than 2 but equal to or less than i, and p represents a natural number equal to or greater than 1 but less than m.

2. The light guide according to claim 1, wherein: The second reflecting surface is arranged to be farther from the light emitting unit than the light path separating component, and In which, the optical path separation component is configured to transmit light reflected at a first reflection angle on the second reflection surface and traveling toward the optical path separation component, and to make light reflected at a second reflection angle larger than the first reflection angle on the second reflection surface and traveling toward the optical path separation component be reflected toward the second reflection surface.

3. The light guide according to claim 2, in, The light guide unit includes a first reflecting surface and a second reflecting surface facing each other and parallel to each other, and at least one light path separation component arranged between the first reflecting surface and the second reflecting surface. wherein the at least one optical path separation component is separated from the light incident portion, The second reflecting surface is configured to be farther away from the light emitting unit than the light path separation component. Wherein, the optical path separation component has a surface facing the second reflecting surface, and The critical angle of light incident on the surface of the optical path separation component facing the second reflection surface is greater than the critical angle of light incident on the second reflection surface.

4. The light guide according to any one of claims 2 to 3, in, The light guide unit includes a plurality of sub-reflection surfaces which are parallel to the second reflection surface and do not overlap with each other. Wherein, the light guiding unit includes a plurality of image extraction units, and light is extracted to the first reflection surface side through the plurality of image extraction units between a pair of adjacent sub-reflection surfaces and between the second reflection surface and a sub-reflection surface adjacent to the second reflection surface among the plurality of sub-reflection surfaces.

5. The light guide according to claim 4, in, The distance between the plurality of sub-reflection surfaces and the first reflection surface becomes narrower as the distance from the light incident portion increases.

6. The light guide according to claim 4, in, Each of the plurality of image extraction units is a reflection surface forming an obtuse angle with the second reflection surface.

7. The light guide according to claim 4, further comprising: At least one optical path separation component between the first reflective surface and at least half of the plurality of image capture units.

8. The light guide according to any one of claims 2 to 3, in, The light comprises a plurality of bundles of light beams, and Wherein, the multiple bundles of light beams having the same viewing angle are parallel to each other.

9. A virtual image display device, comprising: Image display element; The light guide according to any one of claims 1 to 8, and an optical system configured to allow image light emitted from the image display element to enter the light incident portion of the light guide, The light guide guides the image light emitted from the image display element and emits the image light to form a virtual image.

10. The virtual image display device according to claim 9, wherein: The collimated light is incident on the light incident portion.

11. The virtual image display device according to claim 9, in, Satisfaction relationship W2'≥2×W2 Here, W2′ represents the beam width of the light initially reflected by the second reflection surface at the second reflection angle, W2 represents the beam width of light primarily reflected by the second reflecting surface at the second reflection angle in the region where the optical path separation component is provided, and Among them, the following formula holds W2 / (sin(θ2))=d, Here, θ2 represents the second reflection angle, W2 represents the beam width of light primarily reflected by the second reflecting surface at the second reflection angle in the region where the optical path separation component is provided, and d represents the distance between the second reflecting surface and the optical path separation component.

12. The virtual image display device according to claim 9, in, The following formula is established W1 / (2×sin(θ1))=D Here, W1 represents the beam width of the light reflected by the second reflection surface at the first reflection angle, θ1 represents the first reflection angle, and D represents the distance between the first reflecting surface and the second reflecting surface.

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