Patent Publication Number: US-11028991-B1

Title: Vehicle lighting device and vehicle lamp

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-214993, filed on Nov. 28, 2019; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Exemplary embodiments described herein relate to a vehicle lighting device and a vehicle lamp. 
     BACKGROUND 
     From the viewpoints of energy saving and long operational lifetime, a vehicle lighting device provided with a light-emitting diode is widely used instead of a vehicle lighting device provided with a filament. 
     In addition, in order to downsize the vehicle lighting device, a plurality of chip-shaped light-emitting diodes may be used. The plurality of light-emitting diodes are mounted on a substrate. In addition, a frame portion that surrounds the plurality of light-emitting diodes and a sealing portion that is provided on an inner side of the frame portion to cover the plurality of light-emitting diodes are provided on the substrate. 
     In addition, in order to improve light extraction efficiency or to easily obtain desired light distribution characteristics, there is suggested a technology of providing a lens on a sealing portion. When providing the lens on the sealing portion, the lens is held by a vacuum chuck or the like and the lens is mounted on the sealing portion. 
     Here, the lens is formed from a material having a light-transmitting property, but it is preferable that the lens is formed from a light-transmitting resin in consideration of the manufacturing cost. However, the light-transmitting resin may have tackiness (stickiness). When the tackiness of the lens is strong, detachment from the vacuum chuck or the like is hindered, and thus there is a concern that a lens mounting position may be deviated. When the lens mounting position deviates, there is a concern that desired light distribution characteristics and the like may not be obtained. In addition, when integrating or transporting a plurality of lenses, the lenses may adhere to each other, or the lens may adhere to an accommodation member such as a tray. 
     Here, it is desired to develop a technology capable of suppressing tackiness of optical elements such as a lens. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view illustrating a vehicle lighting device according to an embodiment. 
         FIG. 2  is a cross-sectional view taken along line A-A. 
         FIG. 3A  is a schematic side view illustrating an optical element, and  FIG. 3B  is a schematic enlarged view of a portion B. 
         FIGS. 4A to 4C  are schematic partial cross-sectional views illustrating tackiness of the optical element. 
         FIGS. 5A and 5B  are schematic views illustrating an optical element according to another embodiment. 
         FIG. 6  is a schematic partial cross-sectional view illustrating a vehicle lamp. 
     
    
    
     DETAILED DESCRIPTION 
     A vehicle lighting device according to an embodiment includes a socket, a substrate that is provided on one end portion side of the socket, a frame portion that is provided on the substrate, at least one light-emitting element that is provided in a region on an inner side of the frame portion on the substrate, a sealing portion that is provided on an inner side of the frame portion and covers the light-emitting element, and an optical element that is provided on the sealing portion. An arithmetic-average roughness value of a first surface on the sealing portion side in the optical element is greater than an arithmetic-average roughness value of a second surface on a side opposite to the first surface. 
     Hereinafter, an embodiment will be described with reference to the accompanying drawings. Note that, in the drawings, the same reference numeral will be given to the same element, and detailed description thereof will be appropriately omitted. 
     (Vehicle Lighting Device) 
     A vehicle lighting device  1  according to this embodiment can be provided, for example, in an automobile, a rail way vehicle, or the like. Examples of the vehicle lighting device  1  provided in the automobile include lamps which are used as a front combination light (in which for example, a daytime running lamp (DRL), a position lamp, a turn signal lamp, and the like are appropriately combined), a rear combination light (in which for example, a stop lamp, a tail lamp, a turn signal lamp, a back lamp, a fog lamp, and the like are appropriately combined), and the like. However, applications of the vehicle lighting device  1  are not limited to the lamps. 
       FIG. 1  is a schematic perspective view illustrating the vehicle lighting device  1  according to the embodiment. 
       FIG. 2  is a cross-sectional view taken along line A-A in the vehicle lighting device  1  in  FIG. 1 . 
     As illustrated in  FIG. 1  and  FIG. 2 , a socket  10 , a light-emitting module  20 , a power supply unit  30 , and a heat transfer portion  40  can be provided in the vehicle lighting device  1 . 
     The socket  10  can include a mounting portion  11 , a bayonet  12 , a flange  13 , and a thermal radiation fin  14 . 
     The mounting portion  11  can be provided on a surface of the flange  13  which is opposite to a side in which the thermal radiation fin  14  is provided. An external shape of the mounting portion  11  can be set to a columnar shape. For example, the external shape of the mounting portion  11  is a circular column shape. The mounting portion  11  can include a concave portion  11   a  that is opened to an end portion on a side opposite to the flange  13  side. 
     At least one slit  11   b  can be provided in the mounting portion  11 . Respective portions of a substrate  21  can be provided inside the slit  11   b . A dimension (width) of the slit  11   b  in a peripheral direction of the mounting portion  11  can be set to be slightly greater than dimensions of the respective portions of the substrate  21 . In this case, positioning of the substrate  21  can be performed by inserting the respective portions of the substrate  21  into the inside of the slit  11   b.    
     In addition, when the slit  11   b  is provided, a planar shape of the substrate  21  can be enlarged. According to this, the number of elements mounted on the substrate  21  can be increased. Alternatively, since the external size of the mounting portion  11  can be decreased, downsizing of the mounting portion  11  and downsizing of the vehicle lighting device  1  can be realized. 
     In addition, a concave portion  11   c  that is opened to a bottom surface  11   a   1  of the concave portion  11   a  can be provided. The heat transfer portion  40  can be provided in the concave portion  11   c.    
     The bayonet  12  can be provided on an outer side surface of the mounting portion  11 . For example, the bayonet  12  protrudes toward an outer side of the vehicle lighting device  1 . The bayonet  12  can face the flange  13 . A plurality of the bayonets  12  can be provided. The bayonet  12  can be used when mounting the vehicle lighting device  1  to a casing  101  of a vehicle lamp  100 . The bayonet  12  can be used for twist lock. 
     The flange  13  can be set to have a plate shape. For example, the flange  13  can be set to have a circular plate shape. An outer side surface of the flange  13  can be located on a further outer side of the vehicle lighting device  1  in comparison to an outer side surface of the bayonet  12 . 
     The thermal radiation fin  14  can be provided in the flange  13  on a side opposite to the mounting portion  11  side. As the thermal radiation fin  14 , at least one piece can be provided. For example, a plurality of thermal radiation fins are provided in the socket  10  illustrated in  FIG. 1  and  FIG. 2 . A plurality of the thermal radiation fins  14  can be provided in parallel in a predetermined direction. The thermal radiation fins  14  can be set to have a plate shape. 
     In addition, a hole  10   b  into which a connector  105  is inserted can be provided in the socket  10 . The connector  105  including a sealing member  105   a  can be inserted into the hole  10   b . According to this, a cross-sectional shape and a cross-sectional dimension of the hole  10   b  can be set to be appropriate for a cross-sectional shape and a cross-sectional dimension of the connector  105  including the sealing member  105   a.    
     The socket  10  can have a function of holding the light-emitting module  20  and the power supply unit  30 , and a function of transferring heat generated in the light-emitting module  20  to the outside. According to this, it is preferable that the socket  10  is formed from a material such as a metal having high heat conductivity. 
     In addition, in recent years, the socket  10  is desired to efficiently radiate heat generated in the light-emitting module  20  and to be light in weight. According to this, it is more preferable that the socket  10  is formed from highly heat conductive resin. Examples of the highly heat conductive resin include a filler using a resin and an inorganic resin. For example, the highly heat conductive resin may be obtained by mixing a filler using carbon, aluminum oxide, or the like with a resin such as polyethylene terephthalate (PET) and nylon. 
     According to the socket  10  which includes the highly heat conductive resin and in which the mounting portion  11 , the bayonet  12 , the flange  13 , and the thermal radiation fin  14  are integrally formed, heat generated in the light-emitting module  20  can be efficiently radiated. In addition, the weight of the socket  10  can be reduced. In this case, the mounting portion  11 , the bayonet  12 , the flange  13 , and the thermal radiation fin  14  can be integrally formed by using an injection molding method, or the like. In addition, the socket  10  and the power supply unit  30  can be integrally formed by using an insert molding method, or the like. 
     The light-emitting module  20  can be provided on a surface of the heat transfer portion  40  on a side opposite to the bottom surface side of the concave portion  11   c.    
     The light-emitting module  20  can include a substrate  21 , a light-emitting element  22 , a resistor  23 , a control element  24 , a frame portion  25 , a sealing portion  26 , and an optical element  27 . 
     For example, the substrate  21  can be bonded onto the heat transfer portion  40 . That is, the substrate  21  can be provided on one end portion side of the socket  10 . Note that, an adhesive adapted to bond the substrate  21  to the heat transfer portion  40  can be the same adhesive adapted to bond the heat transfer portion  40  to the inside of the concave portion  11   c  as described later. The substrate  21  can be set to have a plate shape. For example, a planar shape of the substrate  21  can be set to a square shape. For example, the substrate  21  can be formed from an inorganic material such as ceramics (for example, aluminum oxide, aluminum nitride, and the like), an organic material such as paper phenol and glass epoxy. In addition, the substrate  21  may be obtained by coating a surface of a metal plate with an insulating material. Note that, when coating the surface of the metal plate with the insulating material, the insulating material may include an organic material, or may include an inorganic material. If the light-emitting element  22  generates a large amount of heat, it is preferable to form the substrate  21  by using a material with high heat conductivity from the viewpoint of thermal radiation. Examples of the material with high heat conductivity include ceramics such as aluminum oxide and aluminum nitride, a highly heat conductive resin, a material obtained by coating a surface of a metal plate with an insulating material, and the like. In addition, the substrate  21  may have a single layer structure or a multi-layer structure. 
     In addition, an interconnection pattern  21   a  may be provided on the surface of the substrate  21 . For example, the interconnection pattern  21   a  can be formed from a material containing silver as a main component, a material containing copper as a main component, or the like. 
     The light-emitting element  22  can be provided in the substrate  21  on a side opposite to the heat transfer portion  40  side. As the light-emitting element  22 , at least one piece can be provided. That is, at least one piece of the light-emitting element  22  can be provided on the substrate  21  in a region on an inner side of the frame portion  25 . In the case of the vehicle lighting device  1  illustrated in  FIG. 1  and  FIG. 2 , a plurality of the light-emitting elements  22  are provided. Note that, when providing a plurality of the light-emitting elements  22 , the plurality of light-emitting elements  22  can be connected in series. In addition, the light-emitting element  22  and the resistor  23  can be connected in series. 
     The light-emitting element  22  can be a light-emitting diode, an organic light-emitting diode, a laser diode, or the like. 
     The light-emitting element  22  can be a chip-shaped light-emitting element. According to the chip-shaped light-emitting element  22 , since a region in which the light-emitting element  22  is provided can be reduced, downsizing of the substrate  21  and downsizing of the vehicle lighting device  1  can be realized. The chip-shaped light-emitting element  22  can be mounted with a chip on board (COB). The light-emitting element  22  can be an upper and lower electrode type light-emitting element, an upper electrode type light-emitting element, or a flip chip type light-emitting element. The light-emitting element  22  illustrated in  FIG. 1  and  FIG. 2  is the upper and lower electrode type light-emitting element. In the upper and lower electrode type light-emitting element or the upper electrode type light-emitting element, the light-emitting element  22  can be electrically connected to the interconnection pattern  21   a  through a wire interconnection  21   b . For example, the light-emitting element  22  can be electrically connected to the interconnection pattern  21   a  by using a wire bonding method. In the flip chip type light-emitting element, the light-emitting element  22  can be directly mounted on the interconnection pattern  21   a.    
     A light emission surface of the light-emitting element  22  faces a front surface side of the vehicle lighting device  1 . The light-emitting element  22  emits light mainly toward the front surface side of the vehicle lighting device  1 . The number, the size, arrangement, and the like of the light-emitting element  22  can be appropriately changed in correspondence with the size, applications, and the like of the vehicle lighting device  1  without being limited to the exemplified configurations. 
     The resistor  23  can be provided in the substrate  21  on a side opposite to the heat transfer portion  40 . The resistor  23  can be electrically connected to the interconnection pattern  21   a . For example, the resistor  23  can be a surface mount type resistor, a resistor including a lead wire (a metal oxide film resistor), a film-shaped resistor formed by using a screen printing method, or the like. The resistor  23  illustrated in  FIG. 1  is a film-shaped resistor. 
     A material of the film-shaped resistor can be, for example, ruthenium oxide (RuO 2 ). The film-shaped resistor can be formed by using, for example, a screen printing method and a firing method. If the resistor  23  is a film-shaped resistor, a contact area between the resistor  23  and the substrate  21  can be increased, and thus a heat dissipation property can be improved. In addition, a plurality of the resistors  23  can be formed at a time. According to this, productivity can be improved. In addition, a variation in resistance values of the plurality of resistors  23  can be suppressed. 
     Here, since a variation exists in forward voltage characteristics of the light-emitting element  22 , when an application voltage between an anode terminal and a ground terminal is set to be constant, a variation occurs in brightness of light emitted from the light-emitting element  22  (light flux, luminance, light intensity, and illuminance). According to this, a value of a current flowing through the light-emitting element  22  can be set within a predetermined range by the resistor  23  so that the brightness of the light emitted from the light-emitting element  22  is set within the predetermined range. In this case, the value of the current flowing through the light-emitting element  22  can be set within a predetermined range by changing a resistance value of the resistor  23 . 
     If the resistor  23  is the surface mount type resistor, the resistor including a lead wire, or the like, a resistor  23  having an appropriate resistance value in correspondence with the forward voltage characteristics of the light-emitting element  22  can be selected. If the resistor  23  is the film-shaped resistor, when a part of the resistor  23  is removed, the resistance value can be increased. The number, the size, arrangement, and the like of the resistor  23  is not limited to the example, and can be appropriately changed in correspondence with the number, specifications, and the like of the light-emitting element  22 . 
     The control element  24  can be provided in the substrate  21  on a side opposite to the heat transfer portion  40  side. The control element  24  can be electrically connected to the interconnection pattern  21   a . The control element  24  can be provided so that a reverse voltage is not applied to the light-emitting element  22 , and so that a pulse noise from a reverse direction is not applied to the light-emitting element  22 . For example, the control element  24  can be a diode. For example, the control element  24  can be a surface mount type diode, a diode including a lead wire, or the like. The control element  24  illustrated in  FIG. 1  is the surface mount type diode. 
     In addition, a pull-down resistor can be provided for detection of conduction relating to the light-emitting element  22 , prevention of erroneous lighting, or the like. In addition, a cover portion that covers the interconnection pattern  21   a , the film-shaped resistor, or the like can be provided. For example, the cover portion can include a glass material. 
     The frame portion  25  can be provided in the substrate  21  on a side opposite to the heat transfer portion  40  side. The frame portion  25  can be bonded onto the substrate  21 . The frame portion  25  can be set to have a frame shape. At least one piece of the light-emitting element  22  can be provided in a region surrounded by the frame portion  25 . For example, the frame portion  25  can surround a plurality of the light-emitting elements  22 . 
     Note that, description has been given of an example in which the frame portion  25  is molded by using the injection molding method, or the like, and the molded frame portion  25  is bonded to the substrate  21 , but there is no limitation to the example. For example, the frame portion  25  can be formed by applying a molten resin onto the substrate  21  in a frame shape by using a dispenser or the like and by curing the resin. 
     In addition, the frame portion  25  can have a function as a reflector that reflects light emitted from the light-emitting element  22 . 
     The sealing portion  26  can be provided on an inner side of the frame portion  25 . The sealing portion  26  can be provided to cover a region surrounded by the frame portion  25 . The sealing portion  26  can be provided to cover the light-emitting element  22  and the wire interconnection  21   b . The sealing portion  26  can be formed from a material having light-transmitting property. For example, the sealing portion  26  can be formed by filling the region surrounded by the frame portion  25  with a resin. Filling with the resin can be performed, for example, by using a dispenser or the like. For example, the filling resin can be a silicone resin or the like. In addition, a phosphor can be included in the sealing portion  26 . For example, the phosphor can be a YAG-based phosphor (yttrium-aluminum-garnet-based phosphor). However, the type of phosphor can be appropriately changed so as to obtain a predetermined emission color in correspondence with the application of the vehicle lighting device  1 . 
     The optical element  27  can be provided on the sealing portion  26 . For example, the optical element  27  can be provided to perform diffusion, condensing, or the like with respect to light emitted from the light-emitting element  22 . As an example, the optical element  27  illustrated in  FIG. 1  and  FIG. 2  is a convex lens. The optical element  27  that is the convex lens is configured to condense light to obtain predetermined light distribution characteristics. Note that, the optical element  27  is not limited to the convex lens, and may be, for example, a concave lens, a light guide, or the like. 
     Note that, details of the optical element  27  will be described later. 
     The power supply unit  30  can have a power supply terminal  31  and a holding portion  32 . 
     The power supply terminal  31  can be set as a rod-shaped body. The power supply terminal  31  can protrude from the bottom surface  11   a   1  of the concave portion  11   a . A plurality of the power supply terminals  31  can be provided. The plurality of power supply terminals  31  can be aligned in a predetermined direction. The plurality of power supply terminals  31  extend through the inside of the holding portion  32 . End portions of the plurality of power supply terminals  31  on the light-emitting module  20  side can be soldered to the interconnection pattern  21   a  provided in the substrate  21 . End portions of the plurality of power supply terminals  31  on the thermal radiation fin  14  side can be exposed to the inside of the hole  10   b . A connector  105  can be inserted around the plurality of power supply terminals  31  exposed to the inside of the hole  10   b . For example, the power supply terminals  31  can be formed from a metal such as a copper alloy. Note that, the number, a shape, arrangement, a material, and the like of the power supply terminals  31  are not limited to the example, and can be appropriately changed. 
     As described above, it is preferable that the socket  10  is formed form a material having high heat conductivity. However, the material having high heat conductivity may have electrical conductivity. For example, a high heat conductive resin or the like that uses a filler including carbon has electrical conductivity. According to this, the holding portion  32  can be provided to insulate the power supply terminals  31  and the socket  10  having electrical conductivity from each other. In addition, the holding portion  32  can have a function of holding the plurality of power supply terminals  31 . Note that, when the socket  10  is formed from the high heat conductive resin (for example, a high heat conductive resin including a filler that includes aluminum oxide) having an insulating property, the holding portion  32  can be omitted. In this case, the socket  10  can hole the plurality of power supply terminals  31 . 
     The holding portion  32  can be formed from a resin having an insulating property. For example, the holding portion  32  can be inserted into a hole  10   a  provided in the socket  10 , or can be bonded to an inner wall of the hole  10   a.    
     The heat transfer portion  40  can be provided inside the concave portion  11   c  provided in one end portion of the socket  10 . For example, the heat transfer portion  40  can be bonded to the inside of the concave portion  11   c . It is preferable that an adhesive used in bonding of the heat transfer portion  40  is set as an adhesive having high heat conductivity. For example, the adhesive can be set as an adhesive in which a filler using an inorganic material is mixed. For example, heat conductivity of the adhesive can be set to 0.5 to 10 W/(m·K). In this case, a layer formed when the adhesive is cured becomes a heat transfer layer  41 . 
     In addition, the heat transfer portion  40  can be provided inside the concave portion  11   c  through a layer including heat conductive grease (thermal radiation grease). For example, the heat conductive grease can be obtained by mixing a filler using an inorganic material in modified silicone. For example, heat conductivity of the heat conductive grease can be set to 1 to 5 W/(m·K). In this case, a layer that is provided between the heat transfer portion  40  and an inner wall of the concave portion  11   c  and includes the heat conductive grease becomes the heat transfer layer  41 . 
     For example, the heat transfer portion  40  is provided in order for heat generated in the light-emitting module  20  to be easily transferred to the socket  10 . According to this, it is preferable that the heat transfer portion  40  is formed from a material having high heat conductivity. The heat transfer portion  40  has a plate shape, and can be formed from, for example, a metal such as aluminum, an aluminum alloy, copper, and a copper alloy. For example, a planar shape of the heat transfer portion  40  can be set to approximately the same shape as a planar shape of the substrate  21 . However, the heat transfer portion  40  can be provided with a groove or a hole for preventing short-circuiting with the plurality of power supply terminals  31 . For example, planar dimensions of the heat transfer portion  40  can be set to approximately the same planar dimensions as planar dimensions of the substrate  21 . 
     When the heat transfer portion  40  is provided inside the concave portion  11   c  through bonding or through the layer including the heat transfer grease, the layer formed from the adhesive or the layer including the heat conductive grease becomes a buffer material against heat stress or vibration, and thus occurrence of a gap between the heat transfer portion  40  and the socket  10  or detachment of the heat transfer portion  40  can be suppressed. 
     Note that, if heat generated in the light-emitting module  20  is less, the heat transfer portion  40  can be omitted. When the heat transfer portion  40  is omitted, for example, the light-emitting module  20  can be bonded to the bottom surface  11   a   1  of the concave portion  11   a , or the like. 
     Next, the optical element  27  will be further described. 
       FIG. 3A  is a schematic side view illustrating the optical element  27 . 
       FIG. 3B  is a schematic enlarged view of a portion B in the optical element  27  in  FIG. 3A . 
     As illustrated in  FIG. 3A , the optical element  27  can include an optical unit  27   a  (corresponding to an example of a second optical unit), an optical unit  27   b  (corresponding to an example of a first optical unit), and a flange  27   c . The optical unit  27   a , the optical unit  27   b , and the flange  27   c  can be integrally formed. 
     The optical unit  27   a  protrudes to a side of the flange  27   c  which is opposite to the sealing portion  26  side. The optical unit  27   a  has a shape protruding in a direction along a central axis  27   d  of the optical element  27 . An outer surface  27   a   1  of the optical unit  27   a  can be set to a convex curved surface. 
     The optical unit  27   b  protrudes a side of the flange  27   c  which is the sealing portion  26  side. The optical unit  27   b  has a shape protruding to a side opposite to the optical unit  27   a  in the direction along the central axis  27   d  of the optical element  27 . An outer surface  27   b   1  of the optical unit  27   b  can be set to a convex curved surface. A central axis of the optical unit  27   a  and a central axis of the optical unit  27   b  can be set to overlap the central axis  27   d  of the optical element  27 . The optical unit  27   a  and the optical unit  27   b  can have a convex lens function. 
     Note that, the optical unit  27   b  can be omitted. Even when the optical unit  27   b  is omitted, the optical unit  27   a  can retain the convex lens function. However, if the optical unit  27   b  is provided, when pressing the optical element  27  against a material of the sealing portion  26  before being cured, it is easy to push the material of the sealing portion  26  to an outer side of the frame portion  25 . According to this, it is easy to discharge air trapped between the optical element  27  and the material of the sealing portion  26 . In addition, it is possible to suppress excessive pressure from acting on the light-emitting element  22  or the wire interconnection  21   b.    
     The flange  27   c  can be set to have a plate shape. For example, the flange  27   c  can be set to have a ring shape. In the direction along the central axis  27   d  of the optical element  27 , the flange  27   c  is located between the optical unit  27   a  and the optical unit  27   b . In a direction orthogonal to the central axis  27   d  of the optical element  27 , the flange  27   c  is provided on an outer side of the optical unit  27   a  and the optical unit  27   b . For example, the flange  27   c  can be provided to surround a peripheral edge of the optical unit  27   a  and a peripheral edge of the optical unit  27   b.    
     The optical element  27  can be formed from a light-transmitting material. The light-transmitting material can be glass, but it is preferable that the optical element  27  is formed from a light-transmitting resin in consideration of a reduction in the manufacturing cost. The optical element  27  including the light-transmitting resin can be formed by, for example, an injection molding method, a mold molding method, or the like. 
     In this case, when considering that a temperature of the optical element  27  rises due to heat generated when the light-emitting element  22  is turned on, it is preferable to use a light-transmitting resin having heat resistance. In addition, since light emitted from the light-emitting element  22  or sunlight includes ultraviolet rays, it is preferable to use a translucent resin having resistance to ultraviolet rays. In consideration of the above-described circumstances, it is more preferable that the optical element  27  include a silicone resin. 
     Here, the light-transmitting resin such as the silicon resin may have tackiness (stickiness). If the tackiness of the optical element  27  is strong, the optical element  27  may stick to a holding member or an accommodation member, or a plurality of the optical elements  27  may stick to each other. 
       FIGS. 4A to 4C  are schematic partial cross-sectional views illustrating tackiness of the optical element  27 . 
     When providing the optical element  27  on the sealing portion  26 , for example, each of the optical elements  27  can be suctioned by a vacuum chuck  200  as illustrated in  FIG. 4A . According to this, if the tackiness of the optical element  27  is strong, the optical element  27  may stick to an end portion  200   a  of the vacuum chuck  200 . When the optical element  27  is mounted on the sealing portion  26 , the vacuum chuck  200  releases suctioning of the optical element  27 , but when the optical element  27  sticks to the end portion  200   a  of the vacuum chuck  200 , detachment of the optical element  27  is hindered, and thus there is a concern that a mounting position of the optical element  27  may be deviated. When the mounting position of the optical element  27  deviates, there is a concern that desired light distribution characteristics and the like may not be obtained. Note that, this is also true of a case where the optical element  27  is held by a chuck including an opening and closing claw or the like. 
     In addition, when a plurality of the optical elements  27  are put in a bag or the like and are collectively conveyed, or when the plurality of optical elements  27  are put into a hopper or the like, the optical elements  27  may stick to each other as illustrated in  FIG. 4B . When the optical elements  27  stick to each other, a process of separating the optical elements  27  occurs. 
     In addition, when the optical element  27  is accommodated in an accommodation member  201  such as a tray, as illustrated in  FIG. 4C , the optical elements  27  and the accommodation member  201  may stick to each other. When the optical element  27  and the accommodation member  201  stick to each other, there is a concern that detachment of the optical element  27  is hindered, and thus suctioning by the vacuum chuck  200  may not be performed, a position of the optical element  27  that is held may deviate, or the posture of the optical element  27  may be unstable. 
     According to the finding obtained by the present inventors, when the arithmetic-average roughness Ra of an outer surface of the optical element  27  is set to 0.3 to 2.0 μm, tackiness of the optical element  27  is suppressed, and an influence on the optical characteristics of the optical element  27  decreases. In this case, a total region of the outer surface of the optical element  27  may be set to the above-described roughness, or a partial region of the outer surface of the optical element  27  may be set to the above-described roughness. However, if the region having the above-described roughness becomes broad, tackiness of the optical element  27  can be effectively suppressed. 
     For example, a surface of a mold that is used in injection molding or mold molding is set to 0.3 to 2.0 μm in terms of the arithmetic-average roughness Ra, the roughness of the outer surface of the optical element  27  can be set to the above-described range. For example, when the surface of the mold is subjected to a blast treatment, the roughness of the mold can be set to the above-described range. Note that, if using a mold that is not subjected to the blast treatment, the roughness of the outer surface of the optical element  27  becomes 0.2 μm or less in terms of the arithmetic-average roughness Ra. 
     In addition, as illustrated in  FIG. 3B , a plurality of fine concave portions  27   b   1   a  are provided in a surface, which comes into contact with the sealing portion  26 , on an outer surface of the optical element  27 . A part of the sealing portion  26  is provided inside the plurality of concave portions  27   b   1   a , and thus joining strength between the optical element  27  and the sealing portion  26  can be enlarged. 
     Here, when the arithmetic-average roughness Ra is further increased, tackiness of the optical element  27  can be further weakened. In addition, the joining strength between the optical element  27  and the sealing portion  26  can be further enlarged. However, when the arithmetic-average roughness Ra is further increased, there is a concern that an influence on the optical characteristics of the optical element  27  may excessive increase. 
     In this case, in a side surface  27   c   1  of the flange  27   c  on the optical unit  27   a  side, and a side surface  27   c   2  of the flange  27   c  on the optical unit  27   b  side, the influence on the optical characteristics of the optical element  27  is small. Accordingly, the roughness of the surfaces  27   c   1  and  27   c   2  can be further increased. According to the finding obtained by the present inventors, when at least any one of the arithmetic-average roughness Ra of the surface  27   c   1 , and the arithmetic-average roughness Ra of the surface  27   c   2  is set to 0.3 to 2.0 μm, it is possible to sufficiently weaken the tackiness of the optical element  27 . 
     In addition, as described above, the outer surface  27   b   1  of the optical unit  27   b  comes into contact with a material of the sealing portion  26  before being cured. According to this, the inside of the fine concave portions  27   b   1   a  provided in the outer surface  27   b   1  can be filled with the material of the sealing portion  26 . When a part of the sealing portion  26  is provided inside the concave portions  27   b   1   a , even when the arithmetic-average roughness Ra of the outer surface  27   b   1  of the optical unit  27   b  is set to 0.3 to 2.0 μm, it is possible to further suppress an influence on the optical characteristics of the optical unit  27   b . In this case, when a difference between a refractive index of the optical unit  27   b  and a refractive index of the sealing portion  26  decreases, an influence on the optical characteristics of the optical unit  27   b  can be further reduced by the roughness of the outer surface  27   b   1 . According to this, it is preferable that the material of the optical element  27  and the material of the sealing portion  26  are set to the same as each other. For example, the optical element  27  can include a silicone resin, and the sealing portion  26  can include the silicon resin. 
     Note that, the roughness of the outer surface  27   a   1  of the optical unit  27   a  has a great influence on the optical characteristics of the optical unit  27   a , and optical characteristics of the optical element  27 . In this case, when the arithmetic-average roughness Ra of the outer surface  27   a   1  of the optical unit  27   a  is set to 1.0 μm or less, it is possible to reduce the influence on the optical characteristics of the optical element  27 . However, when considering the optical characteristics of the optical element  27 , it is preferable that the arithmetic-average roughness Ra of the outer surface  27   a   1  of the optical unit  27   a  is set to 0.2 μm or less. For example, the blast treatment may not be performed with respect to a portion corresponding to the outer surface  27   a   1  of the optical unit  27   a.    
       FIGS. 5A and 5B  are schematic views illustrating an optical element according to another embodiment. 
     As illustrated in  FIG. 5A , only the above-described optical element  27   a  is provided in an optical element  127 . As described above, when the arithmetic-average roughness Ra of an outer surface of the optical element  127  is set to 0.3 to 2.0 μm, tackiness of the optical element  127  is suppressed, and an influence on optical characteristics of the optical element  127  decreases. 
     In addition, as in the above-described outer surface  27   b   1 , a surface  27   a   2  of the optical element  127  on the sealing portion  26  side comes into contact with the material of the sealing portion  26  before being cured. Accordingly, even when the arithmetic-average roughness Ra of the surface  27   a   2  is set to 0.3 to 2.0 μm, an influence on the optical characteristics of the optical element  127  can be suppressed. In addition, tackiness of the optical element  127  can be sufficiently weakened, or joining strength between the optical element  127  and the sealing portion  26  can be enlarged. 
     The roughness of the outer surface  27   a   1  of the optical element  127  (optical unit  27   a ) has a great influence on the optical characteristics of the optical element  127 , and thus the roughness can be set to 1.0 μm or less in terms of the arithmetic-average roughness Ra. In this case, as in the case of the above-described optical element  27 , it is more preferable that the arithmetic-average roughness Ra of the outer surface  27   a   1  is set to 0.2 μm or less. 
     Note that, when viewed from a direction along a central axis  127   a  of the optical element  127 , a region  127   b  of the outer surface  27   a   1  which overlaps the frame portion  25  has a relative small influence on the optical characteristics of the optical element  127 . Accordingly, the arithmetic-average roughness Ra of the region  127   b  may be set to 0.3 to 2.0 μm. 
     As illustrated in  FIG. 5B , only the optical unit  27   a  and the optical unit  27   b  are provided in an optical element  227 . As described above, when the arithmetic-average roughness Ra of an outer surface of the optical element  227  is set to 0.3 to 2.0 μm, tackiness of the optical element  227  is suppressed, and an influence on the optical characteristics of the optical element  227  decreases. 
     In addition, as described above, a surface  27   b   1  of the optical element  227  on the sealing portion  26  side comes into contact with the material of the sealing portion  26  before being cured. Accordingly, even when the arithmetic-average roughness Ra of the surface  27   b   1  is set to 0.3 to 2.0 μm, an influence on the optical characteristics of the optical element  227  can be suppressed. In addition, tackiness of the optical element  227  can be sufficiently weakened, or joining strength between the optical element  227  and the sealing portion  26  can be enlarged. 
     The roughness of an outer surface  27   a   1  of the optical element  227  (optical unit  27   a ) has a great influence on the optical characteristics of the optical element  227 , and thus the roughness can be set to 1.0 μm or less in terms of the arithmetic-average roughness Ra. In this case, as in the case of the above-described optical element  27 , it is more preferable that the arithmetic-average roughness Ra of the outer surface  27   a   1  is set to 0.2 μm or less. 
     Note that, when viewed from a direction along a central axis  227   a  of the optical element  227 , a region  227   b  of the outer surface  27   a   1  which overlaps the frame portion  25  has a relatively small influence on the optical characteristics of the optical element  227 , and thus the arithmetic-average roughness Ra of the region  227   b  may be set to 0.3 to 2.0 μm. 
     Note that, the above-described flange  27   c  is not provided in the optical elements  127  and  227 . In this manner, the flange  27   c  may be omitted. However, when the flange  27   c  is provided, as illustrated in  FIG. 4A , holding of the optical element  27  by the vacuum chuck  200  or the like becomes easy. In addition, the posture of the optical element  27  held by the vacuum chuck  200  or the like can be stable. 
     (Vehicle Lamp) 
     Next, a vehicle lamp  100  will be described. 
     Note that, in the following description, as an example, a case where the vehicle lamp  100  is a front combination light provided in an automobile will be described. However, the vehicle lamp  100  is not limited to the front combination light provided in an automobile. The vehicle lamp  100  may be a vehicle lamp that is provided in an automobile, a railway vehicle, and the like. 
       FIG. 6  is a schematic partial cross-sectional view illustrating the vehicle lamp  100 . 
     As illustrated in  FIG. 6 , the vehicle lighting device  1 , a casing  101 , a cover  102 , an optical element  103 , a sealing member  104 , and a connector  105  can be provided in the vehicle lamp  100 . 
     The vehicle lighting device  1  can be attached to the casing  101 . The casing  101  can hold the mounting portion  11 . The casing  101  can have a box shape in which one end side is opened. For example, the casing  101  can be formed from a resin or the like through which light is not transmitted. An attaching hole  101   a , into which a portion of the mounting portion  11  in which the bayonet  12  is provided is inserted, can be provided in a bottom surface of the casing  101 . A concave portion into which the bayonet  12  provided in the mounting portion  11  is inserted can be provided in a peripheral edge of the attaching hole  101   a . Note that, a case where the attaching hole  101   a  is directly provided in the casing  101  has been described, but a mounting member including the attaching hole  101   a  may be provided in the casing  101 . 
     When attaching the vehicle lighting device  1  to the vehicle lamp  100 , a portion of the mounting portion  11  in which the bayonet  12  is provided is inserted into the attaching hole  101   a , and the vehicle lighting device  1  is rotated. In this case, for example, the bayonet  12  is held to a fitting portion provided in the peripheral edge of the attaching hole  101   a . This attaching method is referred to as twist-lock. 
     The cover  102  can be provided to clog an opening of the casing  101 . The cover  102  can be formed from a light-transmitting resin or the like. The cover  102  can be set to have a function of a lens or the like. 
     Light emitted from the vehicle lighting device  1  is incident to the optical element  103 . The optical element  103  can perform reflection, diffusion, guiding, condensing, formation of a predetermined light distribution pattern of light emitted from the vehicle lighting device  1 , and the like. For example, the optical element  103  illustrated in  FIG. 6  is a reflector. In this case, the optical element  103  can form a predetermined light distribution pattern by reflecting light emitted from the vehicle lighting device  1 . 
     The sealing member  104  can be provided between the flange  13  and the casing  101 . The sealing member  104  can be set to have an annular shape. The sealing member  104  can be formed from a material having elasticity such a rubber and a silicone resin. 
     When the vehicle lighting device  1  is attached to the vehicle lamp  100 , the sealing member  104  is inserted between the flange  13  and the casing  101 . According to this, an inner space of the casing  101  can be hermetically sealed by the sealing member  104 . In addition, the bayonet  12  is pressed against the casing  101  due to an elastic force of the sealing member  104 . According to this, the vehicle lighting device  1  can be suppressed from being detached from the casing  101 . 
     The connector  105  can be inserted around end portions of the plurality of power supply terminals  31  exposed to the inside of the hole  10   b . A power supply and the like (not illustrated) can be electrically connected to the connector  105 . According to this, it is possible to electrically connect the power supply and the like, and the light-emitting element  22  to each other by inserting the connector  105  around end portions of the terminals of the plurality of power supply terminals  31 . 
     In addition, the sealing member  105   a  can be provided in the connector  105 . When the connector  105  including the sealing member  105   a  is inserted into the hole  10   b , the hole  10   b  is water-tightly sealed. The sealing member  105   a  has an annular shape, and can be formed from a material having elasticity such as a rubber and a silicone resin. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. Moreover, above-mentioned embodiments can be combined mutually and can be carried out.