JP2012230925A - Lighting device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device capable of improving intensity while raising reflection efficiency of light.SOLUTION: The lighting device includes a frame made of a metal material such as stainless steel, and a light guide plate formed on the frame. The light guide plate, especially, is fixed to the frame by means of insert molding. Thus, combination force between the frame and the light guide plate can be improved. Consequently, the lighting device with high intensity hardly damaged by shocks such as falling can be obtained. Further, a reflective film having a reflection rate higher than that of an internal surface of the frame is arranged between the frame and the light guide plate, and the reflective film is fixed to at least either the frame or the light guide plate. With this arrangement, reflection efficiency of light to a light guide plate side can be enhanced, and the lighting device with high luminance can be obtained.

Description

  The present invention relates to an illuminating device suitably used for an electro-optical device.

  In a liquid crystal device as an example of an electro-optical device, an illumination device is provided on the back side of a liquid crystal display panel in order to perform transmissive display. In general, an illuminating device includes a light source, a light guide plate that irradiates the back surface of the liquid crystal display panel with light from the light source as planar light, and a reflection sheet disposed on the opposite side of the light guide plate from the liquid crystal display panel side And various optical sheets disposed on the liquid crystal display panel side of the light guide plate.

  For example, Patent Document 1 describes a liquid crystal display device including an illumination device having this type of configuration. The liquid crystal display device described in Patent Document 1 includes a liquid crystal panel, an FPC, and a lighting device, and each of those constituent elements is sandwiched between a first outer frame and a second outer frame formed of metal such as stainless steel. It is housed in the state. In particular, in this lighting device, a light guide made of translucent resin is fitted into an inner frame made of plastic, and a reflective layer is arranged between the light guide and the second outer frame.

  Patent Document 2 describes a transfer foil for a light guide plate that can sufficiently obtain luminance by sufficiently reflecting and diffusing light on the side surface of the light guide plate.

JP 2006-38900 A Japanese Patent No. 2747670

  In the liquid crystal display device described in Patent Document 1, a light guide made of a light-transmitting resin is fitted into an inner frame made of plastic, and a reflective layer is disposed between the light guide and the second outer frame. However, the light guide, the reflective layer, and the second outer frame are not integrally formed. Therefore, when an impact such as dropping is applied to the liquid crystal display device, the light guide is brought into contact with the light guide made of a light-transmitting resin and the second outer frame made of a metal such as stainless steel. May be damaged.

  The present invention has been made in view of the above points, and provides an illuminating device, a manufacturing method thereof, an electro-optical device, and an electronic apparatus capable of improving strength while improving light reflection efficiency. Is an issue.

  In one aspect of the present invention, an illumination device includes a frame and a light guide formed in close contact with the inside of the frame by insert molding, and a cross section in the height direction of the side surface of the frame. The inner side surface and a convex portion protruding from the inner side surface toward the inside of the frame are formed, and the material for forming the light guide body flows into the convex portion and is cured by the insert molding. In a state, the light guide is fixedly fixed to the frame. Thereby, the improvement of the coupling | bonding force of a flame | frame and a light-guide plate can be aimed at. As a result, it is possible to obtain a high-intensity lighting device that is not easily damaged by an impact such as dropping.

  In another aspect of the present invention, the manufacturing method of the lighting device includes an insert molding step of forming a light guide plate in close contact with the inside of the frame by insert molding, and the cross section in the height direction of the side surface of the frame includes: An inner side surface and a convex portion protruding from the inner side surface toward the inside of the frame are formed, and in the insert molding process, the light guide body forming material flows into the convex portion and is cured. The light guide is closely fixed to the frame in a state.

Sectional drawing which shows the structure of the liquid crystal device which has an illuminating device which concerns on embodiment of this invention. The top view of the illuminating device which concerns on embodiment etc. of this invention. Sectional drawing which shows the structure of the illuminating device which concerns on the modifications 1 and 2. FIG. The principal part perspective view which shows the example of the surface treatment process to the upper surface of a flame | frame. The flowchart of the manufacturing method of the illuminating device of this invention is shown. Sectional drawing which shows the manufacturing process of the illuminating device of this invention. FIG. 14 is a perspective view of an electronic device including the liquid crystal device of the invention.

  6, 6x, 6y frame, 7 reflective film, 8, 8z light guide plate, 50 liquid crystal display panel, 51, 51x, 51y, 51p, 51z illumination device, 100 liquid crystal device

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the present invention is applied to a liquid crystal device as an example of an electro-optical device.

[Configuration of liquid crystal device]
FIG. 1 is a cross-sectional view showing a configuration of a liquid crystal device 100 having an illumination device 51 according to the present embodiment. FIG. 2A is a plan view of the illumination device 51 viewed from the opposite side to the observation side in FIG. In FIG. 2A, for convenience, the reflective film 7, the diffusion sheet 9, and the prism sheet 10, which are constituent elements of the lighting device 51, only show regions (regions surrounded by a two-dot chain line).

  The liquid crystal device 100 includes a liquid crystal display panel 50 and an illumination device 51 that illuminates the liquid crystal display panel 50.

  The liquid crystal display panel 50 is a transmissive or transflective liquid crystal display panel, and is made of a first substrate 1 made of a light-transmitting material such as glass or quartz, and the same material as the first substrate 1. The second substrate 2 formed in this manner is bonded to each other through a frame-shaped sealing material 3, and the liquid crystal layer 4 is sandwiched between the two substrates. In the liquid crystal display panel 50, for example, a black matrix, a color filter, electrodes, and many other components are formed in a matrix shape (lattice shape) or a stripe shape (line shape). Yes. In the present invention, the liquid crystal display panel 50 is not limited to a specific configuration, and may adopt various known configurations.

  The illumination device 51 mainly includes a frame 6, a light source 11 such as an LED (Light Emitting Diode), a reflection film 7 formed on the frame 6, a light guide plate 8 formed on the reflection film 7, and a light guide plate. 8 and various optical sheets disposed on the top. Here, the various optical sheets include a diffusion sheet 9 that scatters light, a prism sheet 10 that focuses light toward the liquid crystal display panel 50 side, and the like. However, in the present invention, it is not essential to provide these optical sheets for the illumination device 51.

  The frame 6 has a box shape and is made of a metal material such as stainless steel. The upper surface 6u of the frame 6 has flatness, and the frame 6 accommodates the light guide plate 8, the diffusion sheet 9, the prism sheet 10, and the like.

  The light source 11 is arranged in the frame 6 along the outer surface (hereinafter also referred to as “light incident end surface”) 8se of the light guide plate 8 facing the light source 11 at an appropriate interval. The present invention is not limited to this, and an opening (not shown) may be provided on the side surface of the frame 6 and the light source 11 may be disposed at a position corresponding to the opening (not shown) of the frame 6. Each light source 11 emits light when a driving current is supplied through a flexible substrate (not shown), and the emitted light L enters the light guide plate 8 through the light incident end face 8se of the light guide plate 8.

  The reflective film 7 is, for example, a metal film having a higher reflectance than the frame 6, and is formed or vapor-deposited on the upper surface 6 u of the frame 6 using a known vapor deposition method or the like. For this reason, the reflective film 7 is in close contact with or integrated with the upper surface 6 u of the frame 6. In a preferred example, the reflective film 7 is preferably made of one or more of aluminum, silver, and alloys thereof. The reflective film 7 preferably has a higher reflectance than the surface of the frame 6 (for example, the inner surface of the frame 6) facing at least the light guide plate 8. For example, the relative reflectance relationship between the frame 6 and the reflective film 7 can be set such that the reflectance of the inner surface of the frame 6 <the reflectance of the reflective film 7 <the reflectance of the outer surface of the frame 6. Thereby, the utilization efficiency of light can be improved, and it becomes possible to comprise the illuminating device 51 of high brightness.

  The light guide plate 8 is made of a material such as a transparent resin such as an acrylic resin. The light guide plate 8 is formed on the reflective film 7 inside the frame 6 by an insert molding method. In this example, as shown in FIG. 2A, the light guide plate 8 has a rectangular planar shape, and the planar shape is smaller than the planar shape of the frame 6. For this reason, among the four outer surfaces (sides) 8s of the light guide plate 8, three outer surfaces (sides) are in close contact with or fixed to the three inner side surfaces (sides) 6s of the corresponding frame 6, and the light guide plate. The lower surface 8 d of 8 is in close contact with or fixed to the upper surface 7 u of the reflective film 7. Accordingly, in the frame 6, the outer surface of the light guide plate 8 facing the light source 11, that is, the light incident end surface 8 se is not closely attached or fixed to the inner surface 6 s of the frame 6. Thus, the light guide plate 8 is integrated with the frame 6 and the reflective film 7.

  However, in the present invention, the shape of the light guide plate 8 is not limited. For example, when each of the light guide plate 8 and the frame 6 has a polygonal planar shape, a plurality of outer surfaces (sides) of the light guide plate 8 are formed. Of these, at least one outer side surface (side) can be configured to be in close contact with or fixed to at least one inner side surface (side) among the plurality of inner side surfaces (sides) of the frame 6. That is, in the present invention, if at least one outer surface (side) of the plurality of outer surfaces (sides) of the light guide plate 8 is in close contact with or fixed to the inner side surface (side) of the frame 6, it will be described later. This is because the strength of the lighting device 51 can be improved. In the present invention, the light guide plate 8z may be configured to have a notch (or opening) 8k surrounding each light source 11, as shown in FIG. FIG.2 (b) is a top view of the illuminating device 51p corresponding to Fig.2 (a). In the lighting device 51p, the light guide plate 8z has a plurality of notches 8k, and a plurality of outer side surfaces (sides) 8s of the light guide plate 8z are in close contact with or fixed to a plurality of inner side surfaces 6s of the frame 6, respectively. . Thereby, the intensity | strength improvement of the illuminating device 51p can be aimed at. Under this configuration, the light source 11 is disposed in the frame 6 at a position corresponding to each notch 8k.

  In the present invention, the light emitted from the light source 11 is exposed to the outside on the outer surface 8 s facing the light incident end surface 8 se of the light guide plate 8, that is, on the outer surface 8 s of the light guide plate 8. A reflective film may be formed so as not to leak and improve the light utilization efficiency.

  The light guide plate 8 having the above configuration is from the light source 11 arranged along the light incident end face 8se of the light guide plate 8 and at an appropriate interval with respect to the liquid crystal display panel 50 arranged to face the light guide plate 8. It has the role of uniformly irradiating the emitted light L onto the surface of the liquid crystal display panel 50. The light L incident on the inside of the light guide plate 8 from the light incident end face 8se of the light guide plate 8 is repeatedly reflected between the lower surface (reflection surface) 8d and the upper surface (light output surface) 8u of the light guide plate 8. When the angle formed by the light exit surface 8u and the light L exceeds the critical angle, the light L passes through the light exit surface 8u and exits toward the diffusion sheet 9 side. At this time, a part of the light L is also emitted to the reflective film 7 side through the reflective surface 8d, but a part of the light L is formed so as to be in close contact with the reflective surface 8d of the light guide plate 8. 7 is returned to the inside of the light guide plate 8.

  The diffusion sheet 9 has a role of diffusing the light L emitted from the light guide plate 8 side and making the luminance of the light of the display screen in the liquid crystal display panel 50 more uniform. The prism sheet 10 has a role of focusing the light L emitted from the diffusion sheet 9 side to the liquid crystal display panel 50 side.

  Under the above configuration, the light L emitted from each light source 11 passes through the light guide plate 8, the diffusion sheet 9, the prism sheet 10, and the liquid crystal display panel 50 in this order. At this time, alignment control of the liquid crystal layer 4 is performed, and a desired display image is visually recognized by an observer.

(Illumination device strength improvement structure)
Next, the strength improving structure of the illumination device 51 according to the embodiment of the present invention will be described.

  The lighting device 51 according to the present embodiment includes a frame 6, a reflective film 7 such as a metal film formed or deposited on the upper surface 6 u of the frame 6 by a known vapor deposition method, and the upper surface 7 u of the reflective film 7 by insert molding. And a light guide plate 8 formed or formed. In particular, the reflective film 7 has a higher reflectance than the frame 6, and the frame 6, the reflective film 7, and the light guide plate 8 are in close contact with each other. In a preferred example, the reflective film 7 preferably has a higher reflectance than the inner surface of the frame 6. In the present invention, the reflective film 7 may be fixed to at least one of the frame 6 and the light guide plate 8.

  Thereby, the reflection efficiency of the light to the liquid crystal display panel 50 side can be improved, and the illuminating device 51 with high luminance is obtained. Thereby, the coupling force of the frame 6, the reflective film 7 and the light guide plate 8 can be improved. As a result, it is possible to obtain a high-intensity lighting device 51 that is not easily damaged by an impact such as dropping.

  The lighting device according to the present invention includes a frame 6 and a light guide plate 8 formed on the frame 6, and the light guide plate 8 may be configured to be directly fixed to the frame 6 by an insert molding method. Good. Thereby, the coupling force between the frame 6 and the light guide plate 8 can be improved. As a result, it is possible to obtain a high-intensity lighting device that is not easily damaged by an impact such as dropping.

(Intensity improving structure of lighting device according to Modification 1)
Next, with reference to Fig.3 (a), the intensity | strength improvement structure of the illuminating device 51x which concerns on the modification 1 of this invention is described. Fig.3 (a) shows sectional drawing of the illuminating device 51x which concerns on the modification 1 of this invention corresponding to FIG.

  When the illumination device 51x according to the first modification is compared with the illumination device 51 according to the present embodiment described above, both differ only in the configuration of the frame and the light guide plate, and the other configurations are the same. Therefore, below, the same code | symbol is attached | subjected about the element same as said embodiment, and the description is abbreviate | omitted suitably.

  That is, in the illuminating device 51x according to the modified example 1, as shown in FIG. 3A, a convex portion 6a protruding toward the light guide plate 8 is provided on an arbitrary inner side surface 6s of the frame 6x. A concave portion 8 a that fits the convex portion 6 a is provided on an arbitrary outer surface 8 s of the light guide plate 8. Here, the convex portion 6a of the frame 6x and the concave portion 8a of the light guide plate 8 are fitted when the light guide plate 8 is molded with respect to the frame 6x. Specifically, in the manufacturing process of the illumination device 51x, the material for forming the light guide plate 8 is poured into the upper surface 7u of the reflective film 7 inside the frame 6x by insert molding. Next, the material is cured. Thereby, the convex part 6a of the frame 6x and the concave part 8a of the light guide plate 8 are fitted in a state where the frame 6x, the reflective film 7 and the light guide plate 8 are in close contact with each other. In the present invention, the shape and number of the convex portions 6a provided on the inner side surface 6s of the frame 6x and the shape and number of the concave portions 8a of the light guide plate 8 formed in association therewith are not limited.

  For example, in the present invention, from the viewpoint of improving the strength of the illuminating device 51x, the protruding length of the convex portion 6a of the frame 6x is increased, and the depth of the concave portion 8a of the light guide plate 8 correspondingly is increased. Or the convex portions 6a are formed on all (or at least one inner side surface 6s) of the four inner side surfaces 6s of the frame 6x, and the four outer side surfaces 8s of the light guide plate 8 are correspondingly formed. Correspondingly, all (or at least one outer surface 8s) are provided with concave portions 8a that fit into the respective convex portions 6a, or a plurality of convex portions 6a are formed on each inner side surface 6s of the frame 6x. In addition, each outer surface 8s of the light guide plate 8 may be provided with a concave portion 8a that fits each convex portion 6a, or at least one of these configurations may be combined.

  According to such a configuration, the frame 6x and the reflective film 7 are further compared with the illumination device 51 according to the above-described embodiment because the convex portion 6a of the frame 6x and the concave portion 8a of the light guide plate 8 are fitted. And the light guide plate 8 can be improved, and a high-intensity lighting device 51x can be obtained.

(Intensity improving structure of lighting device according to Modification 2)
Next, with reference to FIG.3 (b), the intensity | strength improvement structure of the illuminating device 51y which concerns on the modification 2 of this invention is described. FIG.3 (b) shows sectional drawing of the illuminating device 51y which concerns on the modification 2 of this invention corresponding to FIG.

  When the illumination device 51y according to the second modification is compared with the illumination device 51 according to the present embodiment described above, both differ only in the configuration of the frame and the light guide plate, and the other configurations are the same. Therefore, below, the same code | symbol is attached | subjected about the element same as said embodiment, and the description is abbreviate | omitted suitably.

  That is, in the illuminating device 51y according to the modified example 2, as shown in FIG. 3B, the inner surface 6s of the frame 6y is provided with a recess 6b that is recessed to the side opposite to the light guide plate 8 side. The outer surface 8s of the light guide plate 8 is provided with a convex portion 8b that fits into the concave portion 6b. Here, the concave portion 6b of the frame 6y and the convex portion 8b of the light guide plate 8 are fitted when the light guide plate 8 is molded with respect to the frame 6y, as in the manufacturing process of the lighting device 51x according to the first modification described above. Thereby, the recessed part 6b of the flame | frame 6y and the convex part 8b of the light-guide plate 8 fit in the state which the frame 6y, the reflecting film 7, and the light-guide plate 8 contact | adhered. In the present invention, the shape and number of the concave portions 6b provided on the inner side surface 6s of the frame 6y and the shape and number of the convex portions 8b of the light guide plate 8 formed in association therewith are not limited. Thereby, like the illuminating device 51x which concerns on the modification 1, the improvement of the coupling | bonding force of the flame | frame 6y, the reflecting film 7, and the light-guide plate 8 can be aimed at further, and the high intensity | strength illuminating device 51y is obtained.

(Method for improving the reflection efficiency of the lighting device)
In the illuminating devices 51, 51x, 51y, and 51p (hereinafter, referred to as “illuminating device 51z”) according to the embodiment and the first and second modifications, the frames 6, 6x, and 6y (hereinafter, representatively “ The upper surface 6u of the frame 6) has flatness, but in the present invention, the upper surface 6u of the frame 6 is for improving the light reflection efficiency with respect to the liquid crystal display panel 50 side. Surface treatment processing may be performed.

  Here, FIG. 4A to FIG. 4C are perspective views of relevant parts showing various examples of surface treatment processing on the upper surface 6 u of the frame 6. In FIG. 4A, a prism processing with a triangular cross section is applied to the upper surface 6u of the frame 6, and in FIG. 4B, a linear hairline processing is applied to the upper surface 6u of the frame 6. Further, in FIG. 4C, a triangular pattern of dot patterns is applied to the upper surface 6 u of the frame 6. These surface treatments are merely examples, and various known surface treatments can be employed in the present invention. With these configurations, the reflection efficiency or emission efficiency of light toward the light guide plate 8 can be improved, and a high-luminance illumination device 51z with high light reflection efficiency can be obtained with respect to the liquid crystal display panel 50.

  In addition, in this invention, a various deformation | transformation is possible in the range which does not deviate from the meaning.

[Manufacturing method of lighting device]
Next, with reference to FIG. 5 and 6, the manufacturing method of the illuminating device 51 etc. which concern on embodiment of this invention is demonstrated. FIG. 5 shows a flowchart of the manufacturing method of the lighting device 51 according to the embodiment of the present invention. FIG. 6A to FIG. 6E are cross-sectional views illustrating manufacturing steps of the lighting device 51 according to the embodiment of the present invention.

  The manufacturing method of the illuminating device 51 which concerns on this embodiment is equipped with frame preparation process S1, reflective film formation process S2, light-guide plate shaping | molding process S3, and various optical sheet arrangement | positioning processes S4.

  First, in the method for manufacturing the lighting device 51 according to the present embodiment, as shown in FIG. 6A, a frame 6 formed of a metal material such as stainless steel and having a box shape is prepared (frame preparation step). S1). In this manufacturing method, instead of the frame 6 shown in FIG. 6A, a frame 6x shown in FIG. 3A, a frame 6y shown in FIG. 3B, or the like may be used.

  Next, as shown in FIG. 6B, a reflective film 7 such as a metal film having a higher reflectance than the frame 6 is formed (deposited) on the upper surface 6u of the frame 6 by a vapor deposition method (reflective film forming step S2). ). Thereby, the reflective film 7 and the upper surface 6 u of the frame 6 can be brought into close contact with each other or integrated. In a preferred example, the reflective film 7 is preferably made of one or more of aluminum, silver, and alloys thereof. Thereby, the reflection efficiency of the light with respect to the light-guide plate 8 side can be improved, and the illuminating device 51 with high brightness | luminance is obtained.

  Next, as shown in FIG. 6C, a light guide plate 8 made of a material such as a transparent resin such as an acrylic resin is formed on the upper surface 7u of the reflective film 7 by an insert molding method (light guide plate forming step S3). In particular, in the light guide plate forming step S3, the frame 6, the reflective film 7, and the light guide plate 8 are brought into close contact with each other by an insert forming method. Specifically, the outer surface 8 s of the light guide plate 8 is in close contact with the inner surface 6 s of the frame 6, and the lower surface 8 d of the light guide plate 8 is in close contact with the upper surface 7 u of the reflective film 7. That is, the light guide plate 8 is integrated with the frame 6 and the reflective film 7.

  Thereby, the improvement of the coupling | bonding force of the flame | frame 6, the reflecting film 7, and the light-guide plate 8 can be aimed at. If the frame 6x or the frame 6y described above is used, the convex portion 6a of the frame 6 and the concave portion 8a of the light guide plate 8 are fitted, or the concave portion 6b of the frame 6 and the convex portion 8b of the light guide plate 8 are fitted. Therefore, the coupling force between the frame 6, the reflective film 7, and the light guide plate 8 can be further improved. As a result, it is possible to obtain lighting devices 51, 51x, and 51y having higher strength that are not easily damaged by an impact such as dropping. Further, since the reflective film 7 is covered with the light guide plate 8, corrosion of the reflective film 7 against water droplets can be prevented.

  Next, as shown in FIG. 6 (d), a diffusion sheet 9 is disposed on the light guide plate 8 via an adhesive, and further, an adhesive is applied on the diffusion sheet 9 as shown in FIG. 6 (e). Then, the prism sheet 10 is arranged (various optical sheet arranging steps S4). In this way, the illuminating device 51 which concerns on this embodiment is obtained. If the above-described frame 6x or frame 6y is used, the above-described illumination device 51x or 51y is obtained.

  In addition, it replaces with the manufacturing method of said illuminating device 51, and the manufacturing method of the illuminating device 51 of this invention is equipped with the light-guide plate shaping | molding process S3 which shape | molds the light-guide plate 8 on the flame | frame 6 by an insert molding method at least, and is light-guide plate. In the molding step S3, the light guide plate 8 may be fixed to the frame 6 by an insert molding method. Thereby, the illuminating device 51 which can aim at the improvement of the coupling | bonding force of the flame | frame 6 and the light-guide plate 8 is obtained. As a result, it is possible to obtain a high-intensity lighting device 51 that is not easily damaged by an impact such as dropping.

[Electronics]
Next, a specific example of an electronic device including a liquid crystal device (hereinafter, referred to as “the liquid crystal device 1000 according to the present invention”) having the illumination device 51z according to the present embodiment, the first modification, and the second modification. Will be described with reference to FIG.

  First, an example in which the liquid crystal device 1000 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 7A is a perspective view showing the configuration of this personal computer. As shown in the figure, a personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal device 1000 according to the present invention is applied.

  Next, an example in which the liquid crystal device 1000 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 7B is a perspective view showing the configuration of the mobile phone. As shown in the figure, a cellular phone 720 includes a plurality of operation buttons 721, a reception port 722, a transmission port 723, and a display unit 724 to which the liquid crystal device 1000 according to the present invention is applied.

  In addition, as an electronic device to which the liquid crystal device 1000 according to the present invention can be applied, in addition to the personal computer shown in FIG. 7A and the mobile phone shown in FIG. Monitor direct-view video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, digital still cameras, etc.

Claims (2)

Frame,
A light guide formed in close contact with the inside of the frame by insert molding,
In the cross section in the height direction of the side surface of the frame, an inner surface and a convex portion protruding from the inner surface toward the inside of the frame are formed,
The lighting device is characterized in that the light guide is closely fixed to the frame in a state in which the material for forming the light guide flows into the convex portion and is cured by the insert molding. A method for manufacturing a lighting device, comprising:
By insert molding, it has an insert molding process in which a light guide plate is formed in close contact with the inside of the frame,
In the cross section in the height direction of the side surface of the frame, an inner surface and a convex portion protruding from the inner surface toward the inside of the frame are formed,
In the insert molding process, the light guide is closely fixed to the frame in a state in which a material for forming the light guide flows into the convex portion and is hardened.

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