Wiring board and head-mounted display

Abstract

To provide a wiring board and a head-mounted display whose performance can be improved.SOLUTION: The wiring board comprises: a transparent substrate; a mesh wiring layer disposed on the substrate; and a plurality of electronic components electrically connected to the mesh wiring layer. The mesh wiring layer includes: a first dark-colored layer disposed on the substrate; a metal layer disposed on the first dark-colored layer; and a second dark-colored layer that covers the first dark-colored layer and the metal layer. A plurality of terminal portions are formed in the mesh wiring layer. The plurality of electronic components is disposed spaced apart from each other and mounted on the terminal portions that differ from each other.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] An embodiment of the present disclosure relates to a wiring board and a head-mounted display. [Background technology]

[0002] Currently, mobile terminal devices such as smartphones, tablets, and smart glasses (AR, MR, etc.) are becoming more functional, smaller, thinner, and lighter. These mobile terminal devices use multiple communication bands, requiring multiple antennas corresponding to the communication bands. For example, mobile terminal devices are equipped with multiple antennas, such as a telephone antenna, a Wi-Fi (Wireless Fidelity) antenna, a 3G (Generation) antenna, a 4G (Generation) antenna, a 5G (Generation) antenna, an LTE (Long Term Evolution) antenna, a Bluetooth (registered trademark) antenna, and an NFC (Near Field Communication) antenna. However, as mobile terminal devices become smaller, the space available for antenna installation is limited, limiting the flexibility of antenna design. Furthermore, because antennas are built into a limited space, radio wave sensitivity is not always satisfactory.

[0003] For this reason, film antennas that can be mounted in the display area of ​​mobile terminal devices or the transparent area of ​​smart glasses have been developed. This film antenna is a transparent antenna in which an antenna pattern is formed on a transparent substrate, and the antenna pattern is formed by a mesh-like conductive mesh layer consisting of conductor portions as formed portions of an opaque conductive layer and numerous openings as non-formed portions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-66610 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, in a conventional film antenna, one or more mesh wiring layers are mounted on a transparent substrate. Such mesh wiring layers can be used for functions such as wireless communication or eye tracking. Therefore, there is a demand for improving the performance of such functions.

[0006] The present embodiment provides a wiring board and a head mounted display that can improve performance. [Means for solving the problem]

[0007] The embodiments of the present disclosure relate to the following [1] to [9].

[0008] [1] A wiring board, a transparent substrate; a mesh wiring layer disposed on the substrate; a plurality of electronic components electrically connected to the mesh wiring layer; The mesh wiring layer includes: a first dark layer disposed on the substrate; a metal layer disposed on the first dark layer; a second dark layer covering the first dark layer and the metal layer; A plurality of terminal portions are formed on the mesh wiring layer, The plurality of electronic components are arranged at intervals from one another and are mounted on different terminal portions of the wiring board.

[0009] [2] The wiring board according to [1], wherein the glass transition temperature of the substrate is 150°C or higher and 400°C or lower.

[0010] [3] The wiring board according to [1] or [2], wherein the electronic component includes a light-emitting element.

[0011] [4] The wiring board according to [3], wherein the light emitting element emits light having an infrared wavelength.

[0012] [5] The wiring board according to [1] or [2], wherein the mesh wiring layer is configured as an antenna, and the electronic component includes a semiconductor element for driving the antenna.

[0013] [6] The wiring board according to any one of [1] to [5], wherein the mesh wiring layer is configured as an antenna, and the electronic component includes a light-emitting element and a semiconductor element for driving the antenna.

[0014] [7] The wiring board according to any one of [1] to [6], wherein a dummy wiring layer electrically independent from the mesh wiring layer is provided around the mesh wiring layer.

[0015] [8] [7] A wiring board according to [7], wherein a plurality of the dummy wiring layers are provided, and the aperture ratios of the mesh wiring layer and the dummy wiring layer gradually increase from the mesh wiring layer to the dummy wiring layer farther from the mesh wiring layer.

[0016] [9] The frame and a transparent display attached to the frame; an imaging unit attached to the frame, The display device includes: [1] to [8], and a wiring board according to any one of [1] to [8]. a display unit laminated on the wiring board.

[0017]

[10] the wiring board includes a peripheral portion attached to the frame and a central portion surrounded by the peripheral portion; The head-mounted display according to [9], wherein the electronic components are arranged in the central portion. [Effects of the Invention]

[0018] According to the embodiments of the present disclosure, the performance of the wiring board and the head mounted display can be improved. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view showing a head-mounted display according to an embodiment. [Figure 2] FIG. 2 is a front view (view taken along line II in FIG. 1) showing the head mounted display according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view (cross-sectional view taken along line III-III in FIG. 2) showing the display device of the head-mounted display according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view (cross-sectional view taken along line IV-IV in FIG. 2) showing the display device of the head-mounted display according to the embodiment. [Figure 5] FIG. 5 is an enlarged plan view showing the wiring board according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view (a cross-sectional view taken along line VI-VI in FIG. 5) showing the wiring board according to the embodiment. [Figure 7] FIG. 7 is a cross-sectional view (cross-sectional view taken along line VII-VII in FIG. 5) showing the wiring board according to the embodiment. [Figure 8A] FIG. 8A is a cross-sectional view showing a method for manufacturing a wiring board according to one embodiment. [Figure 8B] FIG. 8B is a cross-sectional view showing the method for manufacturing the wiring board according to the embodiment. [Figure 8C] FIG. 8C is a cross-sectional view showing the method for manufacturing the wiring board according to the embodiment. [Figure 8D] FIG. 8D is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. [Figure 8E]FIG. 8E is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. [Figure 8F] FIG. 8F is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. [Figure 8G] FIG. 8G is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. [Figure 8H] FIG. 8H is a cross-sectional view showing the method for manufacturing the wiring board according to the embodiment. [Figure 8I] FIG. 8I is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. [Figure 8J] FIG. 8J is a cross-sectional view showing a method for manufacturing a wiring board according to an embodiment. [Figure 9] FIG. 9 is a plan view showing a wiring board according to a first modified example. [Figure 10] FIG. 10 is an enlarged plan view showing a wiring board according to a first modified example. [Figure 11] FIG. 11 is a plan view showing a wiring board according to a second modified example. [Figure 12] FIG. 12 is an enlarged plan view showing a wiring board according to a second modified example. [Figure 13] FIG. 13 is a plan view showing a wiring board according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0020] First, one embodiment will be described with reference to Figures 1 to 8J. Figures 1 to 8J are diagrams illustrating this embodiment.

[0021] The figures shown below are schematic diagrams. Therefore, the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, appropriate modifications can be made within the scope of the technical concept. In the figures shown below, the same parts are denoted by the same reference numerals, and some detailed descriptions may be omitted. Furthermore, the numerical values, such as dimensions, and material names of each component described in this specification are examples of embodiments, and are not limited to these and may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are interpreted not only to mean their strict meanings but also to include substantially the same state.

[0022] In the following embodiments, the "X direction" refers to a direction parallel to one side of the wiring board. The "Y direction" refers to a direction perpendicular to the X direction and parallel to another side of the wiring board. The "Z direction" refers to a direction perpendicular to both the X and Y directions and parallel to the thickness direction of the wiring board. The "front surface" refers to the surface on the positive side of the Z direction, which faces the wearer of the head-mounted display. The "rear surface" refers to the surface on the negative side of the Z direction, which is opposite to the surface on the wearer of the head-mounted display.

[0023] The configuration of a head-mounted display (hereinafter simply referred to as HMD) according to this embodiment will be described with reference to Figs. 1 to 7. The HMD according to this embodiment is a transmission type (see-through type) HMD. In this specification, "HMD" refers to a display that is worn on the wearer's head. This HMD also includes smart glasses (AR, MR, etc.).

[0024] As shown in FIGS. 1 and 2, the HMD 90 according to this embodiment includes a frame 91, a transparent display device 95 attached to the frame 91, and an imaging unit 99 (see FIG. 2) attached to the frame 91. In this embodiment, the HMD 90 includes a display device 95 for the right eye and a display device 95 for the left eye, and is a so-called glasses-type HMD. The display device 95 for the right eye and the display device 95 for the left eye have substantially the same structure. The display devices 95 are synchronized with each other and are configured to display the same image on the left and right or corresponding images on the left and right. Furthermore, the two display devices 95 may be individually controllable, and the two display devices 95 may display different images from each other. The HMD 90 may also be a so-called goggle-type HMD that includes a single display device 95.

[0025] A frame 91 of the HMD 90 has a rim 92 and a pair of temples 93 connected to the rim 92. Each display device 95 is fitted into the rim 92. In this embodiment, a wireless communication circuit 94a of the HMD 90 is provided on the rim 92.

[0026] Furthermore, a control unit 94b for controlling each display device 95 is provided on each of the pair of temples 93. This control unit 94b may include an image display unit (not shown) that generates image light. In this embodiment, one control unit 94b is provided on each temple 93. The control unit 94b provided on the right temple 93 controls the display device 95 for the right eye, and the control unit 94b provided on the left temple 93 controls the display device 95 for the left eye.

[0027] Next, the display device 95 will be described. As shown in Fig. 2 and Fig. 3, the display device 95 has a base material 96, a wiring board 10 provided on the base material 96, and a display unit 97 laminated on the wiring board 10 and provided between the base material 96 and the wiring board 10. In this embodiment, the wiring board 10 covers the entire base material 96. Although not shown, the wiring board 10 may cover only a portion of the base material 96.

[0028] The material of the substrate 96 may be any material that is transparent in the visible light region. For example, a glass substrate can be used as the substrate 96. In this embodiment, when the HMD 90 is worn by a wearer, the substrate 96 is disposed farther from the wearer, and the wiring board 10 is disposed closer to the wearer. That is, when the HMD 90 is worn by a wearer, the wiring board 10 is disposed between the substrate 96 and the wearer. This prevents the wiring board 10 from coming into contact with surrounding structures or other people, for example, even if the HMD 90 comes into contact with surrounding structures or other people when worn by the wearer. This prevents the first directional wiring 21 and the second directional wiring 22 of the mesh wiring layer 20 of the wiring board 10 from coming into contact with surrounding structures or other people and becoming disconnected. Note that when the HMD 90 is worn by a wearer, the substrate 96 may be disposed closer to the wearer, and the wiring board 10 may be disposed farther from the wearer.

[0029] In this specification, "having transparency" means that the transmittance of visible light is 85% or more. Visible light refers to light having a wavelength of 400 nm or more and 700 nm or less. Having a visible light transmittance of 85% or more means that when the absorbance of the member to be measured (e.g., substrate 96) is measured, the transmittance is 85% or more over the entire wavelength range of 400 nm or more and 700 nm or less. The absorbance is measured using a spectrophotometer (V-670 spectrometer manufactured by JASCO Corporation).

[0030] The display unit 97 includes a half mirror. This half mirror is a component that superimposes external light in front of the display device 95 with image light from an image display unit (not shown) that generates image light. The display unit 97 is configured so that the image display area is transparent when the image is not displayed, allowing the wearer to view the external world through light that passes through the display unit 97. The wearer can view a virtual image (image) formed by the image light while viewing the external world. In the illustrated example, the display unit 97 is provided at a position overlapping approximately the center of the base material 96 when viewed from the front (see FIG. 2). However, the present invention is not limited to this, and the display unit 97 may be provided at a position overlapping any region of the base material 96 when viewed from the front.

[0031] The display device 95 may be a display device that projects an image using a prism or a hologram, or may be a display device that uses a transmissive liquid crystal display or the like.

[0032] Next, the imaging unit 99 will be described. The imaging unit 99 may be, for example, a camera such as a digital camera that generates an image by capturing an object. In this embodiment, the imaging unit 99 is an infrared camera that can capture infrared light. However, the imaging unit 99 is not limited to this, and may be a camera that can capture visible light. As shown in FIG. 4, the imaging unit 99 captures an image of the wearer's eye. That is, infrared light irradiated onto the wearer's eye by an electronic component (light-emitting element) 17 (described later) is reflected by the wearer's eye, and the reflected light enters the imaging unit 99. Note that the imaging unit 99 may be configured to capture an image obtained by the infrared light reflected by the wearer's eye.

[0033] The control unit 94b detects the position information of the wearer's eyes and the direction of their gaze from the image captured by the imaging unit 99. The control unit 94b may detect the position information of the wearer's eyes and the direction of their gaze using a known gaze detection technology. For example, the control unit 94b may detect the position information of the wearer's eyes and the direction of their gaze based on the positional relationship between the wearer's pupil and a base point obtained by reflecting infrared light off the wearer's cornea. The control unit 94b may also detect the position information of the wearer's eyes and the direction of their gaze based on the position of the iris or pupil. Note that the imaging unit 99 may have a function for detecting the position information of the wearer's eyes and the direction of their gaze.

[0034] The detected position information of the wearer's eyes and the direction of the wearer's gaze can be applied to the calibration of the HMD 90 and the gaze tracking function of the wearer. Calibration of the HMD 90 refers to adjusting the display position of the image on the display unit 97 when the HMD 90 is started up or an application is started up. In this calibration, for example, the display position of the image on the display unit 97 can be adjusted by using the detected position information of the wearer's eyes. In the gaze tracking function of the HMD 90, gaze tracking can be performed by using, for example, the detected direction of the wearer's gaze.

[0035] The image captured by the imaging unit 99 may be transmitted to an external information processing device. In this case, the image received by the external information processing device may be used to detect the position information of the wearer's eyes and the direction of the wearer's line of sight.

[0036] Next, the configuration of the wiring board will be described with reference to Figures 5 to 7. Figures 5 to 7 are diagrams showing the wiring board according to this embodiment.

[0037] The wiring board 10 shown in Figures 5 to 7 is a substrate used in the above-mentioned display device 95 (see Figures 1 and 2). The wiring board 10 includes a transparent substrate 11, a mesh wiring layer 20 disposed on the substrate 11, and a plurality of electronic components 17 electrically connected to the mesh wiring layer 20. Specifically, the wiring board 10 includes a primer layer 15 disposed on the substrate 11, and the mesh wiring layer 20 disposed on the primer layer 15. In addition, a power supply unit 40 is electrically connected to the mesh wiring layer 20.

[0038] The shape of the substrate 11 may be substantially rectangular in plan view. The substrate 11 is transparent and substantially flat, and its thickness is substantially uniform overall. The thickness T1 (see FIG. 6) of the substrate 11 may be, for example, 2 μm or more, 10 μm or more, or 15 μm or more. By making the thickness T1 of the substrate 11 2 μm or more, the strength of the wiring board 10 can be maintained and the first directional wirings 21 and second directional wirings 22 (described later) of the mesh wiring layer 20 can be made less likely to deform. Furthermore, the thickness T1 of the substrate 11 may be, for example, 200 μm or less, 50 μm or less, or 25 μm or less. The planar shape of the substrate 11 may be a rectangle with rounded corners.

[0039] The material of the substrate 11 may be any material that is transparent in the visible light range and electrically insulating. Examples of the material of the substrate 11 include organic insulating materials such as polyester resin, acrylic resin, polycarbonate resin, polyimide resin, polyolefin resin, cellulose resin, polyarylate resin, and fluororesin materials. The polyester resin may be polyethylene terephthalate or the like. The acrylic resin may be polymethyl methacrylate or the like. The polyolefin resin may be cycloolefin polymer or the like. The cellulose resin may be triacetyl cellulose or the like. The fluororesin material may be PTFE or PFA or the like. For example, the material of the substrate 11 may be an organic insulating material such as cycloolefin polymer or polynorbornene polymer (manufactured by Sumitomo Bakelite Co., Ltd.). The material of the substrate 11 may also be glass, ceramics, or the like, appropriately selected depending on the application. While the substrate 11 is illustrated as being composed of a single layer, the present invention is not limited thereto and may have a structure in which multiple substrates or layers are stacked. Furthermore, the substrate 11 may be a film-like member or a plate-like member.

[0040] In the present embodiment, substrate 11 is transparent. Substrate 11 may have a visible light transmittance of 85% or more, or may have a visible light transmittance of 90% or more. There is no particular upper limit to the visible light transmittance of substrate 11, but it may be, for example, 100% or less. By setting the visible light transmittance of substrate 11 to be within the above range, the transparency of wiring board 10 can be increased, and display device 95 can be made easier to view.

[0041] The glass transition temperature of the substrate 11 may be 150°C or higher and 400°C or lower. In this embodiment, as will be described later, the electronic components 17 are mounted directly to the terminal portions 18 formed on the mesh wiring layer 20 without using a flexible printed circuit board or the like. Therefore, since the glass transition temperature of the substrate 11 is 150°C or higher, damage to the substrate 11 due to heat when the electronic components 17 are directly mounted to the terminal portions 18 can be suppressed. Furthermore, since the glass transition temperature of the substrate 11 is 400°C or lower, discoloration of the substrate 11 during the manufacturing process or in the environment in which the finished product is used can be suppressed. Therefore, the yellowness of the substrate 11 can be kept low, and the transparency of the substrate 11 can be ensured.

[0042] Next, the primer layer 15 will be described. The primer layer 15 serves to improve adhesion between the mesh wiring layer 20 and the substrate 11. In this embodiment, the primer layer 15 is provided over substantially the entire first surface 11a of the substrate 11. This eliminates the need for patterning the primer layer 15. This reduces the number of process steps. The primer layer 15 may be provided only in the region of the first surface 11a of the substrate 11 where the mesh wiring layer 20 is provided.

[0043] This primer layer 15 contains a polymer material, which can effectively improve the adhesion between the mesh wiring layer 20 and the substrate 11. In this case, the primer layer 15 can be made of a colorless and transparent polymer material.

[0044] The primer layer 15 may contain an acrylic resin or a polyester resin. This can more effectively improve the adhesion between the mesh wiring layer 20 and the substrate 11. When the primer layer 15 contains an acrylic resin, examples of the acrylic resin include polymers containing acrylic acid, methacrylic acid, and derivatives thereof as monomer components. Examples of the acrylic resin include polymers obtained by copolymerizing acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methacrylic acid, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl acrylate, acrylamide, acrylonitrile, hydroxyl acrylate, or the like as a main component with a monomer copolymerizable therewith (e.g., styrene, divinylbenzene, acrylonitrile, or the like). In addition to the above-mentioned monomers, dimers having two acrylic or methacrylic groups per molecule, or multifunctional urethane acrylates, etc., may be added to the resin as the main component. Organic molecules having two or more epoxy groups per molecule may also be added to the resin as the main component. This crosslinks the acrylic resin, hardening the resin to form the primer layer 15. The cured primer layer exhibits excellent adhesion. It is also possible to achieve excellent water resistance, acid resistance, alkali resistance, solvent resistance, or a combination of these. This prevents the adhesion between the mesh wiring layer 20 and the substrate 11 from decreasing during wiring formation or over time.

[0045] The polymer material of the primer layer 15 may be cured by crosslinking through irradiation with visible light, ultraviolet light, X-rays, electron beams, α-rays, β-rays, γ-rays, etc. This can improve the scratch resistance and heat resistance of the primer layer 15.

[0046] Furthermore, the primer layer 15 may have a visible light transmittance (light with a wavelength of 400 nm or more and 700 nm or less) of 85% or more, or may have a visible light transmittance of 90% or more. There is no particular upper limit to the visible light transmittance of the primer layer 15, but it may be, for example, 100% or less. By setting the visible light transmittance of the primer layer 15 to be within the above range, the transparency of the wiring substrate 10 can be increased, and the display device 95 can be easily viewed.

[0047] The thickness T2 (length in the Z direction, see FIG. 5) of the primer layer 15 may be 0.05 μm or more and 0.5 μm or less. When the thickness T2 of the primer layer 15 is 0.05 μm or more, the adhesion between the mesh wiring layer 20 and the substrate 11 can be effectively improved. Furthermore, when the thickness T2 of the primer layer 15 is 0.5 μm or less, the transparency of the wiring substrate 10 can be ensured.

[0048] In this embodiment, the mesh wiring layer 20 may be configured as an electromagnetic wave transmitting / receiving unit (antenna). In this case, the mesh wiring layer 20 may be configured as an array antenna. When the mesh wiring layer 20 is configured as an array antenna in this way, it is possible to improve the millimeter wave antenna performance for transmitting and receiving millimeter waves with high linearity. Note that an array antenna is an antenna in which multiple antenna elements (radiating elements) are regularly arranged and in which the amplitude and phase of the excitation of the elements can be independently controlled.

[0049] 5 to 7, the mesh wiring layer 20 is formed on the substrate 11. In the illustrated example, the mesh wiring layer 20 exists on the entire surface of the substrate 11. However, this is not limited thereto, and the mesh wiring layer 20 may exist only in a partial region on the substrate 11.

[0050] The mesh wiring layer 20 may be compatible with any of a millimeter wave antenna, a telephone antenna, a WiFi antenna, a 3G antenna, a 4G antenna, a 5G antenna, an LTE antenna, a Bluetooth (registered trademark) antenna, an NFC antenna, etc. If the wiring board 10 does not have a radio wave transmission / reception function, each mesh wiring layer 20 may perform functions such as a hovering function, fingerprint authentication, a heater, noise reduction (shielding), etc. The hovering function refers to a function that allows the user to operate the display without directly touching it.

[0051] 5, the mesh wiring layer 20 has a pattern shape in which metal wires are arranged in a lattice or mesh shape. This pattern shape is repeatedly arranged in the X direction and the Y direction. That is, the mesh wiring layer 20 has a pattern shape consisting of a portion (first-directional wiring 21 described later) extending in a first direction (e.g., Y direction) and a portion (second-directional wiring 22 described later) extending in a second direction (e.g., X direction).

[0052] As shown in FIG. 5, the mesh wiring layer 20 has a plurality of wires. Specifically, the mesh wiring layer 20 has a plurality of first-directional wires 21 and a plurality of second-directional wires 22 connecting the plurality of first-directional wires 21. The plurality of first-directional wires 21 and the plurality of second-directional wires 22 are integrated as a whole to form a lattice or mesh shape. Each of the first-directional wires 21 extends linearly in one direction (Y direction). Each of the second-directional wires 22 extends linearly in another direction (X direction) perpendicular to the one direction. Note that the first-directional wires 21 and the second-directional wires 22 may extend in a direction that is not parallel to either the X direction or the Y direction.

[0053] In the mesh wiring layer 20, a plurality of openings 23 are formed by being surrounded by adjacent first-directional wires 21 and adjacent second-directional wires 22. The transparent substrate 11 is exposed from each opening 23. This can increase the transparency of the wiring board 10 as a whole.

[0054] The planar shape of each opening 23 is approximately square in plan view. That is, the first directional wires 21 and the second directional wires 22 are arranged at equal intervals. The multiple first directional wires 21 are arranged at equal intervals, and the pitch P1 can be, for example, in the range of 0.01 mm to 1 mm. The multiple second directional wires 22 are arranged at equal intervals, and the pitch P2 can be, for example, in the range of 0.01 mm to 1 mm. In this way, by arranging the multiple first directional wires 21 and the multiple second directional wires 22 at equal intervals, the size of the openings 23 in the mesh wiring layer 20 is uniform, making it difficult to see the mesh wiring layer 20 with the naked eye. Furthermore, the pitch P1 of the first directional wires 21 is equal to the pitch P2 of the second directional wires 22. Therefore, each opening 23 is approximately square in plan view, and the transparent primer layer 15 and substrate 11 are exposed through each opening 23. Therefore, by increasing the area of ​​each opening 23, the transparency of the wiring substrate 10 as a whole can be increased. The length L3 of one side of each opening 23 can be, for example, in the range of 0.01 mm to 1 mm. Furthermore, although the first directional wirings 21 and the second directional wirings 22 are orthogonal to each other, this is not limitative and they may intersect at an acute or obtuse angle. Furthermore, the shape of the openings 23 may be the same shape and size over the entire surface, or may vary depending on the location, and need not be uniform over the entire surface.

[0055] As shown in FIG. 6, each of the first-directional wirings 21 has a cross section perpendicular to its longitudinal direction (X-direction cross section) that is substantially rectangular or square. In this case, the cross-sectional shape of the first-directional wirings 21 is substantially uniform along the longitudinal direction (Y-direction) of the first-directional wirings 21. As shown in FIG. 7, each of the second-directional wirings 22 has a cross section perpendicular to its longitudinal direction (i.e., Y-direction cross section) that is substantially rectangular or square, and has substantially the same shape as the cross-sectional shape (X-direction cross section) of the first-directional wirings 21 described above. In this case, the cross-sectional shape of the second-directional wirings 22 is substantially uniform along the longitudinal direction (X-direction) of the second-directional wirings 22. The cross-sectional shapes of the first-directional wirings 21 and the second-directional wirings 22 do not necessarily have to be substantially rectangular or square. For example, the cross-sectional shape of the first direction wiring 21 and the cross-sectional shape of the second direction wiring 22 may be an approximately trapezoid with the front side (positive side in the Z direction) narrower than the back side (negative side in the Z direction), or a shape with curved sides located on both sides in the width direction.

[0056] In this embodiment, the line width W1 of the first directional wiring 21 (see FIG. 6) and the line width W2 of the second directional wiring 22 (see FIG. 7) are not particularly limited and can be appropriately selected depending on the application. Here, the line width W1 of the first directional wiring 21 is the width in a cross section perpendicular to its longitudinal direction (length in the X direction), and the line width W2 of the second directional wiring 22 is the width in a cross section perpendicular to its longitudinal direction (length in the Y direction). For example, the line width W1 of the first directional wiring 21 can be selected from a range of 0.1 μm to 5.0 μm, and may be 0.2 μm to 2.0 μm. Furthermore, the line width W2 of the second directional wiring 22 can be selected from a range of 0.1 μm to 5.0 μm, and may be 0.2 μm to 2.0 μm.

[0057] The height H1 of the first directional wiring 21 (see FIG. 6) and the height H2 of the second directional wiring 22 (see FIG. 7) are not particularly limited and can be appropriately selected depending on the application. Here, the height H1 of the first directional wiring 21 and the height H2 of the second directional wiring 22 are each lengths in the Z direction. The height H1 of the first directional wiring 21 and the height H2 of the second directional wiring 22 can each be selected within the range of 60 nm or more and 5.0 μm or less, for example.

[0058] As shown in FIGS. 6 and 7, the mesh wiring layer 20 includes first dark layers 21c and 22c, metal layers 21m and 22m, and second dark layers 21d and 22d. Among these, the metal layers 21m and 22m include first metal layers 21a and 22a and second metal layers 21b and 22b. The first metal layers 21a and 22a and the second metal layers 21b and 22b may be made of the same metal. In this case, the first metal layers 21a and 22a and the second metal layers 21b and 22b may not be distinguishable from each other. The first metal layers 21a and 22a and the second metal layers 21b and 22b may be distinguishable from each other.

[0059] The above-described first dark color layers 21c, 22c are disposed on the substrate 11. Specifically, the first dark color layers 21c, 22c are disposed on the primer layer 15. The first metal layers 21a, 22a are disposed on the first dark color layers 21c, 22c. The second metal layers 21b, 22b are disposed on the first metal layers 21a, 22a. The second dark color layers 21d, 22d cover the first dark color layers 21c, 22c, the first metal layers 21a, 22a, and the second metal layers 21b, 22b. That is, the first directional wiring 21 has a first dark color layer 21c arranged on the primer layer 15, a first metal layer 21a arranged on the first dark color layer 21c, a second metal layer 21b arranged on the first metal layer 21a, and a second dark color layer 21d covering the first dark color layer 21c, the first metal layer 21a, and the second metal layer 21b. Also, the second directional wiring 22 has a first dark color layer 22c arranged on the primer layer 15, a first metal layer 22a arranged on the first dark color layer 22c, a second metal layer 22b arranged on the first metal layer 22a, and a second dark color layer 22d covering the first dark color layer 22c, the first metal layer 22a, and the second metal layer 22b.

[0060] Of these, the first dark layers 21c and 22c are layers that suppress the reflection of visible light incident on the mesh wiring layer 20 from the substrate 11 side, thereby making the mesh wiring layer 20 less visible to the naked eye.

[0061] The first dark-colored layers 21c, 22c may be dark-colored layers, such as black. The first dark-colored layers 21c, 22c may be formed by performing a darkening treatment (blackening treatment) on a metal layer formed by sputtering, vapor deposition, or the like. In this case, the first dark-colored layers 21c, 22c may be formed as layers made of metal oxide or metal sulfide. The first dark-colored layers 21c, 22c may also be formed as layers containing palladium or tellurium. The first dark-colored layers 21c, 22c may also be formed as dark-colored metal layers on the surface of the primer layer 15 by sputtering, vapor deposition, or the like. In this case, the first dark-colored layers 21c, 22c may be layers made of copper, nickel, or chromium (hereinafter also referred to as copper, etc.). The first dark layers 21c and 22c may be layers made of an alloy of copper or the like, a nitride or oxide of a simple metal such as copper, or a nitride or oxide of an alloy of copper or the like.

[0062] The surface roughness Sa (arithmetic mean height of the surface) of the first dark color layers 21c, 22c may be 5 nm or more and 200 nm or less. When the surface roughness Sa of the first dark color layers 21c, 22c is 5 nm or more, reflection of visible light in the first dark color layers 21c, 22c can be suppressed. This makes it difficult for the mesh wiring layer 20 to be visible to the naked eye of an observer. When the surface roughness Sa of the first dark color layers 21c, 22c is 200 nm or less, it is possible to prevent the haze value of the first dark color layers 21c, 22c from becoming too high. This makes it difficult for an observer to recognize the presence of the first dark color layers 21c, 22c. This makes it difficult for an observer to recognize the mesh wiring layer 20. When measuring the surface roughness Sa of the first dark layers 21c and 22c, a laser microscope (Keyence Corporation, VK-X1000) is used to measure the surface roughness Sa of the rear surface of the first dark layers 21c and 22c in accordance with ISO 25178. When measuring the surface roughness Sa of the first dark layers 21c and 22c, first, the wiring board 10 is set in the laser microscope so that the laser is irradiated onto the wiring board 10 from the second surface 11b side of the substrate 11. The objective lens magnification is set to 50x. In this case, the measurement area is approximately 270 μm × 200 μm. Next, the laser is irradiated onto the wiring board 10 from the second surface 11b side of the substrate 11. In this manner, the surface roughness Sa of the first dark layers 21c and 22c is measured. According to this measurement method, the surface roughness Sa of the first dark color layers 21c and 22c can be measured even after the first metal layers 21a and 22a and the second metal layers 21b and 22b are laminated on the first dark color layers 21c and 22c.

[0063] Thickness d of the first dark layers 21c and 22c 1c , d 2c The thickness d of the first dark color layers 21c and 22c may be 0.1 μm or more and 5.0 μm or less, 0.2 μm or more and 4.5 μm or less, or 0.3 μm or more and 4.0 μm or less. 1c , d 2c When the thickness d of the first dark color layers 21c and 22c is 0.1 μm or more, the adhesion between the primer layer 15 and the first dark color layers 21c and 22c, and the adhesion between the first dark color layers 21c and 22c and the first metal layers 21a and 22a can be improved. 1c, d 2c By making the thickness d of the first dark color layers 21c, 22c 5.0 μm or less, it is possible to prevent the haze value of the first dark color layers 21c, 22c from becoming too high, and it is possible to make it difficult for an observer to recognize the presence of the first dark color layers 21c, 22c. Therefore, it is possible to make it difficult for an observer to recognize the mesh wiring layer 20 with the naked eye. In addition, the thickness d of the first dark color layers 21c, 22c 1c , d 2c By making the thickness 5.0 μm or less, the time required to form the mesh wiring layer 20 can be reduced.

[0064] The first metal layers 21a, 22a serve to improve adhesion between the substrate 11 and the mesh wiring layer 20. The first metal layers 21a, 22a also serve as seed layers when the second metal layers 21b, 22b are formed by electrolytic plating. The first metal layers 21a, 22a may be formed by sputtering, vapor deposition, or the like. The first metal layers 21a, 22a may also be formed by the same method as the first dark color layers 21c, 22c.

[0065] Thickness d of the first metal layers 21a and 22a 1a , d 2a The thickness d of the first metal layers 21a and 22a may be 10 nm or more and 1000 nm or less, 30 nm or more and 500 nm or less, or 50 nm or more and 300 nm or less. 1a , d 2a When the thickness d of the first metal layers 21a and 22a is 10 nm or more, the second metal layers 21b and 22b can be effectively supported when the second metal layers 21b and 22b are formed on the first metal layers 21a and 22a. 1a , d 2a By making the thickness 1000 nm or less, the time required to form the mesh wiring layer 20 can be reduced.

[0066] The second metal layers 21b, 22b serve to increase the height H1 of the first directional wiring 21 and the height H2 of the second directional wiring 22. This reduces the resistance values ​​of the first directional wiring 21 and the second directional wiring 22. The second metal layers 21b, 22b may be formed by plating or the like, or may be formed by electrolytic plating.

[0067] Thickness d of second metal layers 21b and 22b 1b , d 2b The thickness d of the second metal layers 21b and 22b may be 50 nm or more and 4990 nm or less, 100 nm or more and 2000 nm or less, or 200 nm or more and 1800 nm or less. 1b , d 2b When the thickness d of the second metal layers 21b and 22b is 50 nm or more, the height H1 of the first directional wiring 21 and the height H2 of the second directional wiring 22 can be increased, and the resistance values ​​of the first directional wiring 21 and the second directional wiring 22 can be reduced. 1b , d 2b By making the thickness 4990 nm or less, the time required to form the mesh wiring layer 20 can be reduced.

[0068] The first dark layers 21c, 22c and the first metal layers 21a, 22a may have the same crystalline characteristics. On the other hand, the first metal layers 21a, 22a and the second metal layers 21b, 22b may have different crystalline characteristics. The first metal layers 21a, 22a and the second metal layers 21b, 22b may differ from each other in at least one of the crystalline fraction, crystalline structure, crystallite size, and interplanar spacing. For example, the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a measured using CuKα radiation as an X-ray source may be larger than the diffraction angle 2θ of the (111) plane of the second metal layers 21b, 22b. For example, the first metal layers 21a, 22a may have crystalline characteristics such that the diffraction angle 2θ of the (111) plane measured using CuKα radiation as an X-ray source is 43.430° or less. This improves the adhesion between the first dark layers 21c, 22c and the first metal layers 21a, 22a. In this case, the diffraction angle 2θ may be 43.420° or less, or 43.410° or less. The lower limit of the diffraction angle 2θ is not particularly limited, but may be 43.250° or more, 43.300° or more, or 43.350° or more. The diffraction angle is measured using an X-ray diffractometer (Rigaku Corporation, Smart Lab, 9 kW type). The diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a and the diffraction angle 2θ of the (111) plane of the second metal layers 21b, 22b are measured at the power supply unit 40. As described below, the power supply unit 40 is formed simultaneously with the first metal layers 21a, 22a and the second metal layers 21b, 22b by a portion of the second metal film 51 constituting the first metal layers 21a, 22a and a portion of the third metal film 52 constituting the second metal layers 21b, 22b. Therefore, the power supply unit 40 can measure the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a and the diffraction angle 2θ of the (111) plane of the second metal layers 21b, 22b. In this case, the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a can be measured more accurately than when measuring the diffraction angle 2θ of the (111) plane of the first metal layers 21a, 22a in the mesh wiring layer 20 having relatively narrow line widths W1, W2. The measurement conditions are as follows: Measurement mode: 2θ / θ measurement (Out-Plane) X-ray source: Cu-Kα 45kV-50mA Optical system: Concentration method Incident optical system 1: Soller slit 5deg Incident optical system 2: Variable slit (IS) 1 deg Length limit slit: 10 mm Receiving optical system 1: Variable slit (RS1) 1 deg, (RS2) 0.3 mm Receiving optical system 2: PSA OPEN / solar slit 5deg Detector: Scintillation counter Measurement range: 35-80deg Step: 0.02deg Measurement time: 2.0 deg / min

[0069] The second metal layers 21b, 22b may have crystalline properties such that the diffraction angle 2θ of the (111) plane measured using CuKα radiation as an X-ray source is less than 43.4°. This improves the formability of the second metal layers 21b, 22b when they are formed by etching. The diffraction angle 2θ of the (111) plane of the second metal layers 21b, 22b may be 43.390° or less, 43.380° or less, or 43.370° or less.

[0070] Next, the second dark color layers 21d, 22d will be described. The second dark color layers 21d, 22d are layers that suppress reflection of visible light by the mesh wiring layer 20, thereby making the mesh wiring layer 20 less visible to the naked eye. The second dark color layers 21d, 22d cover the entire mesh wiring layer 20. The second dark color layers 21d, 22d may cover the entire power supply section 40.

[0071] The second dark color layers 21d and 22d may be layers of a dark color such as black, etc. The second dark color layers 21d and 22d may also be layers with a roughened surface.

[0072] The surface roughness Sa of the second dark color layers 21d, 22d may be 5 nm or more and 100 nm or less. Having a surface roughness Sa of 5 nm or more reduces reflection of visible light on the surfaces of the second dark color layers 21d, 22d. This makes it difficult for the mesh wiring layer 20 covered with the second dark color layers 21d, 22d to be visible to the naked eye of an observer. Having a surface roughness Sa of 100 nm or less prevents the haze value of the second dark color layers 21d, 22d from becoming too high. This makes it difficult for an observer to recognize the presence of the second dark color layers 21d, 22d. This makes it difficult for an observer to recognize the mesh wiring layer 20 covered with the second dark color layers 21d, 22d. In this case, the surface roughness Sa is determined based on ISO 25178 using a laser microscope (VK-X1000, manufactured by Keyence Corporation).

[0073] The second dark-colored layers 21d, 22d may be formed from a portion of the mesh wiring layer 20 or the power supply unit 40, for example, by subjecting a portion of the metal material constituting the mesh wiring layer 20 or the power supply unit 40 to a darkening treatment (blackening treatment). In this case, the second dark-colored layers 21d, 22d may be formed as a layer made of a metal oxide or a metal sulfide. Alternatively, the second dark-colored layers 21d, 22d may be formed on the surface of the mesh wiring layer 20 or the power supply unit 40 as a coating of a dark material or a plating layer of nickel, chromium, or the like. Furthermore, the second dark-colored layers 21d, 22d may be formed by roughening the surface of the mesh wiring layer 20 or the power supply unit 40.

[0074] The material of the first directional wiring 21 and the second directional wiring 22 may be any conductive metal material. That is, the material of the first dark-colored layers 21c, 22c, the first metal layers 21a, 22a, the second metal layers 21b, 22b, and the second dark-colored layers 21d, 22d may be any conductive metal material. In the present embodiment, the material of the first directional wiring 21 and the second directional wiring 22 is copper, but this is not limited thereto. The material of the first directional wiring 21 and the second directional wiring 22 may be, for example, a metal material such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing these metals. Furthermore, the material of the first metal layers 21a, 22a and the material of the second metal layers 21b, 22b may be the same material. This improves adhesion between the first metal layers 21a, 22a and the second metal layers 21b, 22b.

[0075] The overall aperture ratio At of the mesh wiring layer 20 may be, for example, in the range of 87% or more and less than 100%. By setting the overall aperture ratio At of the mesh wiring layer 20 in this range, the conductivity and transparency of the wiring board 10 can be ensured. The overall aperture ratio At of the mesh wiring layer 20 may be 95% or more and less than 100%. This allows the transparency of the wiring board 10 to be increased while ensuring the conductivity of the wiring board 10. The aperture ratio refers to the ratio (%) of the area of ​​the open area to the unit area of ​​a predetermined region (for example, the entire region of the mesh wiring layer 20). The open area refers to a region where no metal parts such as the first directional wiring 21 and the second directional wiring 22 exist and where the substrate 11 is exposed.

[0076] A plurality of terminal portions 18 are formed on the mesh wiring layer 20. The terminal portions 18 are formed on each of the first directional wirings 21 and the second directional wirings 22. The terminal portions 18 may be formed from the same material as the first directional wirings 21 and the second directional wirings 22. The terminal portions 18 may have dimensions larger than the line width W1 of the first directional wirings 21 and the line width W2 of the second directional wirings 22.

[0077] Next, the electronic component 17 will be described. In this embodiment, the electronic component 17 may be a light-emitting element such as an LED. In this case, the light-emitting element may emit light including infrared wavelengths. In this case, the light-emitting element (LED chip) may have a luminance peak at a dominant wavelength of 840 nm and may have almost no emission intensity below 780 nm. The light-emitting element may also emit light in the visible light band.

[0078] The plurality of electronic components 17 are arranged at intervals from one another and are mounted on different terminal portions 18. In this embodiment, the electronic components 17 are directly mounted on the terminal portions 18 without using a flexible printed circuit board or the like. Each electronic component 17 is connected to two terminal portions 18 so that the equivalent circuit has two poles. In this case, the electronic components 17 are connected to the terminal portion 18 formed on the first directional wiring 21 and the terminal portion 18 formed on the second directional wiring 22.

[0079] Such a wiring board 10 includes a peripheral portion 10a (shaded portion in FIG. 2) attached to the frame 91, and a central portion 10b surrounded by the peripheral portion 10a. The peripheral portion 10a may be an area that is 100 mm or less away from the frame 91. In this embodiment, the electronic components 17 described above are disposed in the central portion 10b. This reduces the energy required to emit light from each electronic component 17 (light-emitting element).

[0080] Although not shown, a protective layer may be formed on the primer layer 15 so as to cover the mesh wiring layer 20. The protective layer protects the mesh wiring layer 20 and is formed so as to cover at least the mesh wiring layer 20 of the substrate 11. Examples of materials that can be used for the protective layer include acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate, modified resins thereof, copolymers thereof, polyvinyl resins such as polyester, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, and polyvinyl butyral, copolymers thereof, polyurethane, epoxy resin, polyamide, and chlorinated polyolefin, and other colorless and transparent insulating resins.

[0081] Referring again to FIG. 2 , the power supply unit 40 is electrically connected to the mesh wiring layer 20. The power supply unit 40 is made of a substantially rectangular conductive thin plate member. The longitudinal direction of the power supply unit 40 is parallel to the X direction, and the lateral direction of the power supply unit 40 is parallel to the Y direction. The power supply unit 40 may be made of a metal material such as gold, silver, copper, platinum, tin, aluminum, iron, or nickel, or an alloy containing these metals. When the wiring board 10 is incorporated into the HMD 90, the power supply unit 40 is electrically connected to a wireless communication circuit 94a (see FIG. 2 ) provided on a frame 91 of the HMD 90. Here, the power supply unit 40 is preferably provided at a position overlapping a rim 92 of the frame 91 when viewed from the front of the HMD 90. This further facilitates connection between the mesh wiring layer 20 and the wireless communication circuit 94a and prevents interference with visibility of the outside world.

[0082] Next, a method for manufacturing wiring board 10 according to this embodiment will be described with reference to FIGS. 8A to 8J.

[0083] First, as shown in Fig. 8A, a substrate 11 is prepared, which includes a first surface 11a and a second surface 11b located on the opposite side of the first surface 11a. The substrate 11 is transparent.

[0084] 8B, a primer layer 15 is formed on the substrate 11. In this case, the primer layer 15 may be formed over substantially the entire first surface 11a of the substrate 11. Methods for forming the primer layer 15 include roll coating, gravure coating, gravure reverse coating, microgravure coating, slot die coating, die coating, knife coating, inkjet coating, dispenser coating, kiss coating, spray coating, screen printing, offset printing, and flexographic printing.

[0085] Next, on the primer layer 15, a mesh wiring layer 20 including a plurality of first directional wires 21 and a plurality of second directional wires 22 connecting the plurality of first directional wires 21 is formed.

[0086] In this case, first, as shown in FIG. 8C , a first metal film 55 is laminated over substantially the entire surface of the primer layer 15. This first metal film 55 is a film for forming the first dark layers 21c and 22c. The first metal film 55 may be formed by a sputtering method, a vapor deposition method, or the like using, for example, copper, an alloy of copper, a nitride or oxide of a single metal such as copper, or a nitride or oxide of an alloy of copper. The thickness of the first metal film 55 may be 10 nm or more and 1000 nm or less. In this embodiment, the first metal film 55 may contain copper.

[0087] As shown in FIG. 8D, a second metal film 51 is laminated over substantially the entire surface of the first metal film 55. This second metal film 51 is a film for forming the first metal layers 21a and 22a. The second metal film 51 may be formed by, for example, a sputtering method. The thickness of the second metal film 51 may be 10 nm or more and 1000 nm or less. In this embodiment, the second metal film 51 may contain copper.

[0088] Next, as shown in FIG. 8E, a third metal film 52 is laminated on the second metal film 51. This third metal film 52 is a film for forming the second metal layers 21b and 22b. The third metal film 52 may be formed by electrolytic plating using the second metal film 51 as a seed layer. The thickness of the third metal film 52 may be 50 nm or more and 4990 nm or less. In this embodiment, the third metal film 52 may contain copper. The step of laminating the first metal film 55 (FIG. 8C) and the step of laminating the second metal film 51 (FIG. 8D) may be performed in a vacuum chamber (not shown). On the other hand, the step of laminating the third metal film 52 (FIG. 8E) may be performed outside the vacuum chamber (not shown).

[0089] 8F, a photo-curable insulating resist 53 is applied to almost the entire surface of the third metal film 52. Examples of the photo-curable insulating resist 53 include organic resins such as acrylic resins and epoxy resins.

[0090] 8G, an insulating layer 54 is formed by photolithography. In this case, the photo-curable insulating resist 53 is patterned by photolithography to form the insulating layer 54 (resist pattern). At this time, the insulating layer 54 is formed so that the third metal film 52 corresponding to the first-directional wiring 21 and the second-directional wiring 22 is exposed.

[0091] 8H , the third metal film 52, the second metal film 51, and the first metal film 55 located on the first surface 11a of the substrate 11 in the portions not covered with the insulating layer 54 are removed. At this time, a wet process using ferric chloride, cupric chloride, a strong acid such as sulfuric acid or hydrochloric acid, persulfate, hydrogen peroxide, or an aqueous solution of these, or a combination of these, is performed to etch the third metal film 52, the second metal film 51, and the first metal film 55 so as to expose the first surface 11a of the substrate 11. In this wet process, the liquid used for the third metal film 52 and the second metal film 51 may be different from the liquid used for the first metal film 55.

[0092] 8I, the insulating layer 54 is removed by wet treatment using a permanganate solution, N-methyl-2-pyrrolidone, an acid or alkaline solution, or dry treatment using oxygen plasma.

[0093] Next, as shown in FIG. 8J, second dark-colored layers 21d and 22d are formed. In this case, second dark-colored layers 21d and 22d may be formed by performing a darkening treatment (blackening treatment) on portions of first metal film 55, second metal film 51, and third metal film 52. Alternatively, second dark-colored layers 21d and 22d may be formed on the surfaces of first metal film 55, second metal film 51, and third metal film 52 as a coating of a dark-colored material or a plating layer of nickel, chromium, or the like. Furthermore, second dark-colored layers 21d and 22d may be formed by roughening the surfaces of first metal film 55, second metal film 51, and third metal film 52.

[0094] In this manner, a wiring board 10 is obtained, which includes the substrate 11, the primer layer 15 provided on the first surface 11a of the substrate 11, and the mesh wiring layer 20 disposed on the primer layer 15. In this case, the mesh wiring layer 20 includes first-directional wiring 21 and second-directional wiring 22. At this time, the power supply section 40 may be formed by a part of the first metal film 55, the second metal film 51, and the third metal film 52.

[0095] 1 is obtained by attaching the wiring board 10 to the base material 96 that is fitted into the rim 92 of the frame 91. Note that the wiring board 10 may be attached to the base material 96 before the base material 96 is fitted into the rim 92 of the frame 91.

[0096] Next, the operation of this embodiment having the above-described configuration will be described.

[0097] 1 and 2, the wiring board 10 is incorporated into the HMD 90 as a component of the display device 95. A control unit 94b of the HMD 90 detects the position information of the wearer's eyes and the direction of the wearer's gaze from an image captured by an imaging unit 99. The detected position information of the wearer's eyes and the direction of the wearer's gaze can be applied to, for example, a gaze tracking function of the wearer.

[0098] According to this embodiment, the wiring board 10 includes a transparent substrate 11, a mesh wiring layer 20 disposed on the substrate 11, and a plurality of electronic components 17 electrically connected to the mesh wiring layer 20. The mesh wiring layer 20 also includes first dark-colored layers 21c and 22c disposed on the substrate 11, first metal layers 21a and 22a disposed on the first dark-colored layers 21c and 22c, second metal layers 21b and 22b disposed on the first metal layers 21a and 22a, and a second dark-colored layer covering the first dark-colored layers 21c and 22c, the first metal layers 21a and 22a, and the second metal layers 21b and 22b. The mesh wiring layer 20 also includes a plurality of terminals 18. The plurality of electronic components 17 are disposed at intervals from one another and are mounted on different terminals 18. This makes it difficult to visually recognize light emitted from the electronic components 17.

[0099] Here, infrared light is typically invisible to the wearer's eyes. On the other hand, when a high-brightness LED is used, the retina detects the light, potentially causing the wearer to perceive brightness. This perception of brightness can lead to the light source entering the wearer's field of vision. When a light source enters the wearer's field of vision, the visibility of the HMD 90 is reduced. This is particularly true when the HMD 90 is used in dark places or at night. Furthermore, for example, if the optic nerve of the retina, which can detect photons, simultaneously receives multiple photons, the optic nerve may perceive the photons as light with higher energy than infrared wavelengths. Furthermore, when light is irradiated toward the eye from a single point in the field of vision, the density of the light as a luminous flux increases, effectively creating a bright spot with high brightness. For example, when two photons strike the cones of the retina, they may be perceived as a single photon with twice the energy. In this case, light with an infrared wavelength of 900 nm may be perceived as green light with a half-wavelength of 450 nm.

[0100] In contrast, in this embodiment, multiple electronic components 17 are arranged at intervals from one another and mounted on different terminal portions 18. This makes it possible to maintain a predetermined illuminance even when a low-illuminance light source is used. Therefore, the wearer's perception of brightness can be suppressed while maintaining a predetermined illuminance. Furthermore, it is presumed that the use of a low-illuminance light source makes it possible to produce diffused light, making the light source less visible.

[0101] Furthermore, in this embodiment, electronic components 17 are mounted directly on terminal portion 18 without using a flexible printed circuit board or the like. In this case, electronic components 17 can be mounted at a higher density and the degree of freedom in placement can be increased compared to a configuration in which electronic components 17 are arranged on an opaque frame 91 or the like. This not only improves structural efficiency but also contributes to improved performance in functions such as wireless communication or eye tracking, where the installation location is important.

[0102] Furthermore, according to the present embodiment, in the HMD 90, the wiring board 10 has the transparent substrate 11 and the mesh wiring layer 20 disposed on the substrate 11, thereby ensuring the transparency of the wiring board 10. As a result, when the wiring board 10 is incorporated into the HMD 90, the outside world can be seen through the openings 23 of the mesh wiring layer 20, and the visibility of the outside world is not obstructed.

[0103] In the above-described embodiment, the electronic component 17 is a light-emitting element, but this is not limiting. For example, the electronic component 17 may be a semiconductor element for driving an antenna. In this case, the wiring board 10 may include multiple types of electronic components 17. For example, the electronic component 17 may include a light-emitting element and a semiconductor element for driving an antenna.

[0104] Next, modified examples of the wiring board will be described.

[0105] Figures 9 and 10 show a first modified example of the wiring board. The modified example shown in Figures 9 and 10 differs in that a dummy wiring layer 30 is provided around the mesh wiring layer 20, and other configurations are substantially the same as the embodiment shown in Figures 1 to 8J described above. In Figures 9 and 10, the same parts as those shown in Figures 1 to 8J are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0106] 9, a dummy wiring layer 30 is provided along the periphery of the mesh wiring layer 20. Unlike the mesh wiring layer 20, this dummy wiring layer 30 does not substantially function as an antenna.

[0107] As shown in FIG. 10, the dummy wiring layer 30 is composed of repeated dummy wirings 30a each having a predetermined unit pattern shape. That is, the dummy wiring layer 30 includes a plurality of dummy wirings 30a of the same shape, and each dummy wiring 30a is electrically independent from the mesh wiring layer 20 (the first-directional wirings 21 and the second-directional wirings 22). The plurality of dummy wirings 30a are regularly arranged throughout the dummy wiring layer 30. The plurality of dummy wirings 30a are spaced apart from each other in the planar direction and are arranged to protrude above the substrate 11. That is, each dummy wiring 30a is electrically independent from the mesh wiring layer 20, the power supply section 40, and other dummy wirings 30a. The shape of each dummy wiring 30a is approximately L-shaped in plan view.

[0108] In this case, the dummy wiring 30a has a shape in which a part of the unit pattern shape (see FIG. 5) of the above-mentioned mesh wiring layer 20 is missing. This makes it difficult to visually recognize the difference between the mesh wiring layer 20 and the dummy wiring layer 30, and makes it difficult to see the mesh wiring layer 20 arranged on the substrate 11.

[0109] As shown in FIG. 10 , the dummy wiring 30a extends parallel to the first-directional wiring 21 or the second-directional wiring 22. Specifically, the dummy wiring 30a includes a first portion 31a extending parallel to the first-directional wiring 21 and a second portion 32a extending parallel to the second-directional wiring 22. The first portion 31a has a shape in which a portion of the first-directional wiring 21 is missing. The second portion 32a has a shape in which a portion of the second-directional wiring 22 is missing. Note that other configurations of the first portion 31a and the second portion 32a are similar to those of the first-directional wiring 21 and the second-directional wiring 22, and therefore detailed description thereof will be omitted here. In this way, the dummy wiring 30a extends parallel to the first-directional wiring 21 or the second-directional wiring 22, making the mesh wiring layer 20 disposed on the substrate 11 even less visible. The aperture ratio of the dummy wiring layer 30 may be the same as or different from the aperture ratio of the mesh wiring layer 20. When the aperture ratio of the dummy wiring layer 30 is different from that of the mesh wiring layer 20 , the aperture ratio of the dummy wiring layer 30 may be close to that of the mesh wiring layer 20 .

[0110] In this way, the dummy wiring layer 30 that is electrically independent from the mesh wiring layer 20 is provided around the mesh wiring layer 20, thereby making the outer edge of the mesh wiring layer 20 unclear. This makes it possible to make the mesh wiring layer 20 less visible on the surface of the image display device 60, and makes it difficult for a user of the HMD 90 to recognize the mesh wiring layer 20 with the naked eye.

[0111] Figures 11 and 12 show a second modified example of the wiring board. The modified example shown in Figures 11 and 12 differs in that two or more dummy wiring layers 30A, 30B having different aperture ratios are provided around the mesh wiring layer 20, but the other configurations are substantially the same as those shown in Figures 1 to 10 described above. In Figures 11 and 12, the same parts as those shown in Figures 1 to 10 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0112] 11, a plurality of (two in this case) dummy wiring layers 30A, 30B (a first dummy wiring layer 30A and a second dummy wiring layer 30B) having different aperture ratios are provided along the periphery of the mesh wiring layer 20. Specifically, the first dummy wiring layer 30A is arranged along the periphery of the mesh wiring layer 20, and the second dummy wiring layer 30B is arranged along the periphery of the first dummy wiring layer 30A. Unlike the mesh wiring layer 20, these dummy wiring layers 30A, 30B do not substantially function as antennas.

[0113] As shown in FIG. 12, the first dummy wiring layer 30A is composed of repeated dummy wirings 30a1 each having a predetermined unit pattern shape. The second dummy wiring layer 30B is composed of repeated dummy wirings 30a2 each having a predetermined unit pattern shape. That is, the dummy wiring layers 30A and 30B each include a plurality of dummy wirings 30a1 and 30a2 each having the same shape, and each dummy wiring 30a1 and 30a2 is electrically independent from the mesh wiring layer 20. The dummy wirings 30a1 and 30a2 are regularly arranged throughout the dummy wiring layers 30A and 30B, respectively. The dummy wirings 30a1 and 30a2 are spaced apart from each other in the planar direction and protrude above the substrate 11. Each dummy wiring 30a1 and 30a2 is electrically independent from the mesh wiring layer 20, the power supply section 40, and the other dummy wirings 30a1 and 30a2. The dummy wirings 30a1 and 30a2 each have a substantially L-shape in plan view.

[0114] In this case, the dummy wirings 30a1 and 30a2 have a shape in which a part of the unit pattern shape (see FIG. 5) of the mesh wiring layer 20 described above is missing. This makes it difficult to visually recognize the difference between the mesh wiring layer 20 and the first dummy wiring layer 30A, and the difference between the first dummy wiring layer 30A and the second dummy wiring layer 30B, and makes it difficult to see the mesh wiring layer 20 arranged on the substrate 11. As shown in FIG. 12, the dummy wirings 30a1 and 30a2 extend parallel to the first directional wiring 21 or the second directional wiring 22. Specifically, the dummy wiring 30a1 includes a first portion 31a1 extending parallel to the first directional wiring 21 and a second portion 32a1 extending parallel to the second directional wiring 22. The dummy wiring 30a2 includes a first portion 31a2 extending parallel to the first directional wiring 21 and a second portion 32a2 extending parallel to the second directional wiring 22.

[0115] The area of ​​each dummy wiring 30a1 in the first dummy wiring layer 30A is larger than the area of ​​each dummy wiring 30a2 in the second dummy wiring layer 30B. In this case, the line width of each dummy wiring 30a1 is the same as the line width of each dummy wiring 30a2, but this is not limited to this, and the line width of each dummy wiring 30a1 may be wider than the line width of each dummy wiring 30a2. Note that other configurations of the dummy wirings 30a1 and 30a2 are similar to the configuration of the dummy wiring 30a in the first modified example, so detailed description will be omitted here.

[0116] In this modification, the aperture ratios of the mesh wiring layer 20 and the two or more dummy wiring layers 30A, 30B may increase stepwise from the mesh wiring layer 20 toward the dummy wiring layers 30A, 30B farther from the mesh wiring layer 20. In other words, the aperture ratios of the dummy wiring layers may gradually increase from those closer to the mesh wiring layer 20 toward those farther from the mesh wiring layer 20. In this case, the aperture ratio of the first dummy wiring layer 30A may be greater than that of the mesh wiring layer 20. The aperture ratio of the second dummy wiring layer 30B may be greater than that of the first dummy wiring layer 30A. This makes it possible to further obscure the outer edges of the mesh wiring layer 20 and the dummy wiring layers 30A, 30B. This makes it possible to make the mesh wiring layer 20 even less visible on the surface of the image display device 60.

[0117] In this way, by arranging the dummy wiring layers 30A and 30B electrically independent from the mesh wiring layer 20, the outer edge of the mesh wiring layer 20 can be made more unclear. This makes it possible to make the mesh wiring layer 20 less visible on the surface of the image display device 60, and makes it difficult for a user of the image display device 60 to recognize the mesh wiring layer 20 with the naked eye. Note that three or more dummy wiring layers having different aperture ratios may be provided around the mesh wiring layer 20.

[0118] Figure 13 shows a third modified example of the wiring board. The modified example shown in Figure 13 differs in the planar shape of the mesh wiring layer 20, but other configurations are substantially the same as those shown in Figures 1 to 12 described above. In Figure 13, the same parts as those shown in Figures 1 to 12 are given the same reference numerals, and detailed explanations will be omitted.

[0119] 13 is an enlarged plan view showing a mesh wiring layer 20 according to a third modified example. In Fig. 13, first-directional wiring 21 and second-directional wiring 22 intersect obliquely (at non-right angles), and the shape of each opening 23 is a rhombus in plan view. The first-directional wiring 21 and the second-directional wiring 22 are not parallel to either the X direction or the Y direction, but either one of the first-directional wiring 21 and the second-directional wiring 22 may be parallel to the X direction or the Y direction.

[0120] The components disclosed in the above-described embodiment and each modification may be combined as needed, or some components may be omitted from all the components shown in the above-described embodiment and each modification.

Claims

1. A wiring board, a transparent substrate; a mesh wiring layer disposed on the substrate; a plurality of electronic components electrically connected to the mesh wiring layer; The mesh wiring layer includes: a first dark layer disposed on the substrate; a metal layer disposed on the first dark layer; a second dark layer covering the first dark layer and the metal layer; A plurality of terminal portions are formed on the mesh wiring layer, The plurality of electronic components are arranged at intervals from one another and are mounted on different terminal portions of the wiring board.

2. 2. The wiring board according to claim 1, wherein the glass transition temperature of the substrate is 150° C. or higher and 400° C. or lower.

3. The wiring board according to claim 1 , wherein the electronic component includes a light-emitting element.

4. The wiring board according to claim 3 , wherein the light emitting element emits light having an infrared wavelength.

5. 2. The wiring board according to claim 1, wherein the mesh wiring layer is configured as an antenna, and the electronic component includes a semiconductor element for driving the antenna.

6. 2. The wiring board according to claim 1, wherein the mesh wiring layer is configured as an antenna, and the electronic component includes a light-emitting element and a semiconductor element for driving the antenna.

7. 2. The wiring board according to claim 1, further comprising a dummy wiring layer provided around said mesh wiring layer and electrically independent from said mesh wiring layer.

8. 8. The wiring board according to claim 7, wherein a plurality of the dummy wiring layers are provided, and the aperture ratios of the mesh wiring layer and the dummy wiring layer increase stepwise from the mesh wiring layer toward the dummy wiring layer farther from the mesh wiring layer.

9. The frame and a transparent display attached to the frame; an imaging unit attached to the frame, The display device includes: The wiring substrate according to any one of claims 1 to 8, a display unit laminated on the wiring board.

10. the wiring board includes a peripheral portion attached to the frame and a central portion surrounded by the peripheral portion; The head mounted display according to claim 9 , wherein the electronic component is disposed in a central portion.

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