LENS FOR DEAD SPOT MONITOR AND DEAD SPOT MONITOR LIGHT EMISSION UNIT AND DEAD SPOT MONITOR LIGHT EMIPENT

Abstract

A lens for a blind-angle monitor and a blind-angle monitor light emission unit, as well as a blind-angle monitor light emitter, are provided to reduce unevenness in the light emission of an icon. A lens 18 for a blind-angle monitor includes a front plate 18a, a rear plate 18c facing the back of the front plate 18a with a cavity 19 between them, a coupling section 18d integrally coupling the front plate 18a and the rear plate 18c around the cavity 19, and an opening 18e allowing the cavity 19 to communicate with an exterior space. The front plate 18a exhibits a transmitting and simultaneously scattering light characteristic. The rear plate 18c exhibits a characteristic of reflecting light and simultaneously scattering light on a front side facing the front plate 18a.The opening 18e is configured to allow light from a light source 20 to enter the cavity 19 through the opening 18e. Light from the light source 20, which passes through the front panel 18a from the back to the front, is used to emit light from an icon.

Description

BACKGROUND OF THE INVENTION Field of invention The present invention relates to a lens for a blind spot monitor and a blind spot monitor light emission unit as well as a blind spot monitor light emitter and reduces an unevenness in the light emission of an icon. Description of the relevant technology A blind spot monitor is a device mounted on a vehicle that detects another vehicle approaching a host vehicle and causes an icon with a predetermined shape to emit light, thereby notifying the driver of the host vehicle of the other vehicle's approach. A blind spot monitor's light emitter is equipped with a lens that receives light from a light source and emits light from its surface. By passing this surface-emitting light through a translucent section in which the icon is inscribed, to shape the light, a display is created that emits light in the shape of the icon. A conventional lens for a blind spot monitor is typically one with a lens cut applied to the surface of a light guide formed from a single colorless and transparent thick plate (e.g., the one described in US 2016 / 0209000 A1). Since the conventional lens is formed from a single thick plate, it is difficult to create a light-emitting surface with uniform brightness across its entire area due to sink marks from the forming process, and unevenness in the light emission of the icon is likely to occur. The present invention provides a lens for a blind-angle monitor and a blind-angle monitor light emission unit, as well as a blind-angle monitor light emitter, which solve the problem described above in the prior art and reduce unevenness in the light emission of an icon. BRIEF SUMMARY OF THE INVENTION A lens for a blind-angle monitor of the present invention comprises: a front plate; a rear plate facing a rear side of the front plate, with a cavity arranged between them; a coupling section integrally coupling the front plate and the rear plate around the cavity; and an opening allowing the cavity to communicate with an exterior space of the cavity, wherein the front plate is configured to have a transmitting and simultaneously scattering light characteristic, the rear plate is configured such that a front side of the rear plate facing the front plate has a reflecting and simultaneously scattering light characteristic, the opening is configured to allow the introduction of light from a predetermined light source into the cavity through the opening, and the lens is configuredTo enable the use of light from the light source, which is transmitted through the front plate from the back of the front plate to a front surface of the front plate, for the emission of light of an icon. With this lens, it is possible to cause the front surface of the front plate to emit light by introducing light from the light source into the cavity between the front and back plates, and the introduced light being reflected and simultaneously scattered by the back plate, and the light being transmitted and simultaneously scattered by the front plate. In this case, the front and back plates can be made of thin plates, since the cavity is positioned between the front and back plates. Thus, compared to a case where the lens is made of a thick plate with a combined size of the front plate,The cavity and the rear plate make it possible to reduce sink marks during molding and to reduce unevenness in the light emission of the icon. In the lens of the present invention, the coupling section can be configured to couple the front plate and the rear plate along a circumferential direction of the cavity (continuously or discontinuously, as described below), and the cavity can be surrounded by the coupling section and formed in a pocket shape. With this configuration, it is possible to restrict the escape of light introduced into the cavity around the cavity and to efficiently cause the front surface of the front plate to emit light, since the cavity is surrounded by the coupling section and formed in a pocket shape. In the lens of the present invention, the opening can be formed between the front plate and the rear plate. With this configuration, the opening can be formed during the manufacturing of the lens by injection molding, by removing a mold that forms the cavity. The rear plate can be inclined relative to the front plate in the direction of the opening. With this configuration, it is possible to efficiently cause the front surface of the front plate to emit light, since light introduced into the cavity can be efficiently reflected by the rear plate and directed to enter the front plate. In the lens of the present invention, the lens can be made from an integrally formed article made of a translucent plastic material, which exhibits characteristics of both transmitting and simultaneously scattering light. With this configuration, it is possible to manufacture the lens, which achieves the effects of the present invention, simply and inexpensively. A blind-angle monitor light emission unit of the present invention comprises: a light source; and a lens that receives light from the light source, transmits the light, and emits the light from a predetermined light emission surface, wherein the lens comprises a front plate having the light emission surface, a rear plate facing a rear side of the front plate, a cavity being arranged between them, and an opening allowing the cavity to communicate with an exterior space of the cavity, the front plate being configured to have a transmitting and simultaneously scattering light characteristic, the rear plate being configured such that a front side of the rear plate facing the front plate has a reflecting and simultaneously scattering light characteristic, and light from the light source being arranged such thatthat the light is introduced into the cavity through the opening. This configuration makes it possible to reduce unevenness in the light emission of the icon. A blind-angle monitor light emitter of the present invention comprises: a light source; a lens that receives light from the light source, transmits the light, and emits the light from a predetermined light-emitting surface; and a translucent section arranged in front of the light-emitting surface, which forms a cross-sectional shape of light emitted from the light-emitting surface in a direction perpendicular to an optical axis into a predetermined icon shape, wherein the lens comprises a front plate having the light-emitting surface, a rear plate facing a rear side of the front plate, with a cavity arranged between them, and an opening that allows the cavity to communicate with an exterior space of the cavity, the front plate being configured to have a characteristic of transmitting light and simultaneously scattering the light.The rear plate is configured such that a front surface of the rear plate facing the front plate exhibits a characteristic of both reflecting and simultaneously scattering light; light from the light source is arranged so that it is directed through the opening into the cavity; and the light source is positioned so that it is not visible through the translucent section when the light-emitting surface is viewed from the front. This configuration reduces unevenness in the icon's light emission caused by point light (a condition in which the light source position appears to shine brightly like a point), as the light source is not directly, or with low probability, visually detected through the light-emitting surface. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional side view showing an embodiment of a lens for a blind spot monitor (hereinafter referred to as "BSM") and a BSM light emission unit and a BSM light emitter according to the present invention, and showing a state in which the BSM light emission unit is mounted on a rear surface (back face) of a mirror plate of an exterior mirror for a vehicle, together with the behavior of light emitted by a switched-on light source; Fig. 2 is a perspective exploded view of the BSM light emission unit and the mirror plate (for a right-side vehicle exterior mirror) in Fig. 1, showing a state viewed diagonally above the front face of the mirror plate; Fig. 3A is a perspective view of the lens of Figs. 1 and 2 viewed diagonally above one of the left and right sides of the back face of the lens; Fig.Figure 3B is a diagram of the lens viewed diagonally above the other from the left and right sides of the rear of the lens; Figure 3C is a front view of the lens (a view from the front of a light-emitting surface); Figure 3D is a rear view (back view) of the lens; Figure 3E is a top view (top view) of the lens; Figure 3F is a bottom view (underside view) of the lens; Figure 3G is a left side view of the lens; Figure 4 is a diagram showing a display position of an icon virtually projected onto the light-emitting surface of the lens and indicated by a dashed line, viewed from the same direction as Figure 3C; and Figure 5 is a diagram of the BSM light-emitting unit of Figure 1 viewed from the front (of the light-emitting surface). DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention is described. It should be noted that here, an upper, a lower, a left, a right, a front, and a rear (backward) direction with respect to an exterior mirror, a lens for a BSM, a BSM light emission unit, and a BSM light emitter are defined as the directions when viewing a mirror surface of the exterior mirror equipped with the BSM light emission unit from the front, wherein the exterior mirror is mounted on a vehicle and arranged in an extended position (the non-retracted position, i.e., the operating position). Fig. 2 shows a BSM light emission unit 12 mounted on a mirror plate 10 of a right-side vehicle exterior mirror, and a BSM light emitter 13, which are shown disassembled into their individual components. A mirror housing of the exterior mirror is not shown.The BSM light emission unit 12 is located and arranged on the rear side of the mirror plate 10 within the mirror housing. This BSM light emission unit 12 is for a right-hand side vehicle mirror. A BSM light emission unit for a left-hand side vehicle mirror (not shown) has a structure that is bilaterally symmetrical to the BSM light emission unit 12 for a right-hand side vehicle mirror. The BSM light emission unit 12 is formed by integrally assembling a housing 14, a printed circuit board (PCB) 16, and a lens 18. The housing 14 is, for example, made of a black opaque resin. In addition to an LED 20, which represents a light source, a connector 22 and other circuit elements are mounted on a lower surface of the PCB 16. The lens 18 is a lens for a BSM according to the present invention.The BSM light emission unit 12 is integrally assembled by inserting the PCB 16 in a horizontal position through a front opening 14a of the housing 14 into an upper part of an interior space 14b, and fitting and attaching the lens 18 into the front opening 14a. A connector insertion port 14c for inserting a connector (not shown) of an external conductor into the interior space 14b and for detachably coupling the connector to the connector 22 of the PCB 16 is formed at a rear end of the housing 14. A translucent section 24 with a predetermined icon shape (here a triangular shape) is formed on a rear surface of a circumferential edge portion of the mirror plate 10 at a right-hand position.The translucent section 24 can be formed, for example, by etching or similar processes onto the back surface of the mirror plate 10 a reflective film 26 in the predetermined icon shape at the position where the icon is to be formed. The integrally assembled BSM light emission unit 12 is adhered and mounted to the back surface of the mirror plate 10 using double-sided adhesive tape 28. A window 28a, open in the predetermined icon shape, is formed within the surface of the double-sided adhesive tape 28.The BSM light emission unit 12 is mounted on the rear surface of the mirror plate 10 by adhering one surface of the double-sided adhesive tape 28 to the rear surface of the mirror plate 10, with the position of the window 28a and the position of the translucent section 24 aligned with each other, and by adhering a light emission surface 12a (a front surface 18a1 of the front plate 18a) of the BSM light emission unit 12 to the other surface of the double-sided adhesive tape 28. The BSM light emitter 13 is formed in this way. The configuration of lens 18 is described with reference to Fig. 3 (Figs. 3A to 3G). Lens 18 is formed, for example, from an integrally molded article made of a translucent plastic material having a translucent milky white color or the like, and exhibiting the characteristics of transmitting and simultaneously scattering light. Such a plastic material could be, for example, a translucent plastic such as PMMA or PC mixed with a white colorant such as titanium dioxide, calcium carbonate, or antimony oxide. Lens 18 can be manufactured by injection molding such a translucent plastic material with a translucent milky white color or the like. Lens 18 comprises a front plate 18a and a rear plate 18c, which faces the rear of the front plate 18a, with a cavity 19 located between them.The front plate 18a has a predetermined thickness and is formed in an essentially vertically elongated rectangular shape. To easily distinguish it from a lens for a left-sided mirror (not shown), a left and a right corner of an upper portion of the vertically elongated rectangle of the front plate 18a are cut obliquely to form a section 18h (Fig. 3C, Fig. 3D). The rear plate 18c has essentially the same thickness as the front plate 18a and is formed in an essentially vertically elongated rectangular shape, smaller than the front plate 18a. Because the cavity 19 is positioned between the front plate 18a and the rear plate 18c, both the front plate 18a and the rear plate 18c can be formed with a thin thickness.Thus, compared to a case where the lens is formed from a solid, thick plate lens with a combined size of the front plate 18a, the cavity 19, and the rear plate 18c, it is possible to reduce sink marks during forming and to minimize unevenness in the light emission of the icon. As shown in Fig. 3D, the rear plate 18c has a smaller surface area than the front plate 18a and is located within the surface of the front plate 18a. The rear plate 18c is inclined obliquely upwards relative to the front plate 18a. This results in the cavity 19 being formed in a wedge shape, narrowing downwards and widening upwards. The left, right, and bottom sides of the cavity 19 are closed by a coupling section 18d, which integrally couples the front plate 18a and the rear plate 18c.An opening 18e, which allows the cavity 19 to communicate with an external space of the cavity 19, is formed on the upper side of the cavity 19. Accordingly, the entire perimeter of the cavity 19, with the exception of the upper opening 18e, is closed by the coupling section 18d, and the cavity 19 is formed in a pocket shape. The size of a region of the cavity 19 is defined such that, when viewed from the front of the front plate 18a, the entire icon is displayed in a position that falls within the region of the cavity 19 (the area enclosed by the coupling section 18d and the opening 18e). A single long and double short dashed line 30 in Fig. 4 indicates a position on the front surface 18a1 of the front plate 18a (the light emission surface 12a), the position being oriented towards the light-transmitting section 24 of the mirror plate 10, i.e. an icon display position.It should be noted that the shape of the icon is formed by the translucent section 24 (Fig. 1, Fig. 2) of the mirror plate 10, which is located on the front side of the front plate 18a. The entire front surface 18a1 of the front plate 18a itself emits light. Both the front surface 18a1 and a rear surface 18a2 of the front plate 18a are designed as smooth surfaces without significant irregularities in order to prevent unevenness in the light emission of the icon, at least at all the positions (parts) where the icon is placed. Two ribs 18f, which support the lower surface of the PCB 16, are formed in a projecting manner on an upper part (at a position that the icon does not overlap when viewed from the front) of the rear surface 18a2 of the front plate 18a.Two projections 18g are formed in a projecting manner on the left and right sides of a lower portion of the rear surface 18a2 of the front plate 18a. These projections 18g are inserted into positioning holes 14d (Fig. 2) of the housing 14 to position the lens 18 within the housing 14. Noses 18i are formed on a right and a left side portion of a central portion in the top-bottom direction of the rear surface 18a2 of the front plate 18a. These noses 18i fit into nose-receiving sections 14f (Fig. 2) formed at corresponding positions on the front opening 14a of the housing 14 to ensure that the lens 18 is fitted into and mounted in the front opening 14a. Fig. 5 shows a state in which the lens 18 is fitted into the front opening 14a and mounted on the housing 14. A section 18c' ( Fig.3B and further) on the left and right sides of the rear plate 18c is formed as an inclined surface, which is obliquely connected to the coupling section 18d. The inclined surface is formed as a result of increasing the thickness of a die for forming the cavity 19 by weld overlay to increase the strength of a tip of the die. Thus, the fact that the area 18c' of the rear plate 18c is formed as the inclined surface is not of particular importance for the function of the rear plate 18c and the inclined surface can be omitted (e.g., the entire rear plate 18c can be formed as a continuous surface such as a flat surface). Fig. 1 shows a state in which the BSM light emission unit 12 of Fig. 2 is glued and mounted to the back surface of the mirror plate 10 with the double-sided adhesive tape 28, and a state in which the LED 20 is switched on to cause the icon to emit light (light emitted by the LED 20 is indicated by arrow 34). The PCB 16 is positioned at a substantially right angle to the surface of the mirror plate 10. An optical axis 20a of the LED 20 is positioned substantially parallel to the surface of the mirror plate 10. The LED 20 is positioned facing downwards towards the cavity 19. A portion of the reflective film 26 (in Fig.(1, where the film thickness of the reflective film is shown to be excessively large) on the back surface of the mirror plate 10 at the location where the icon is to be displayed, is abraded in the icon shape (a triangular shape in front view) to form the translucent section 24. The window 28a is formed in the double-sided adhesive tape 28 such that it does not block the translucent section 24. The LED 20 is positioned so that it is not visible through the translucent section 24 when the light-emitting surface 12a is viewed from the front (the position where the LED 20 is obscured by a non-translucent section around the translucent section 24). The behavior of the light 34 emitted by the LED 20 is described. The light 34 emitted by the LED 20 is introduced into the cavity 19 through the opening 18e. Part of the light 34 introduced into the cavity 19 is applied to the rear plate 18c. Part of the light applied to the rear plate 18c is reflected by a front surface 18c1 of the rear plate 18c and applied to the front plate 18a. Another part of the light applied to the rear plate 18c enters the interior of the rear plate 18c from the front surface 18c1 of the rear plate 18c, is reflected by a dye inside, and is emitted by the front surface 18c1 of the rear plate 18c and applied to the rear surface 18a2 of the front plate 18a.A portion of the light 34 that entered the interior of the rear plate 18c is transmitted through the rear plate 18c and exits from the rear surface 18c2 of the rear plate 18c. However, this exiting light is blocked by the housing 14 and thus does not escape outside the BSM light emission unit 12. Furthermore, another portion of the light 34 introduced into the cavity 19 is applied directly to the rear surface 18a2 of the front plate 18a. The light 34 applied to the rear surface 18a2 of the front plate 18a (the light reflected by the rear plate 18c, the light coming directly from the LED 20, etc.) is transmitted through the front plate 18a with scattering. The transmitted light is shaped into the icon form at the translucent section 24, passes through the mirror plate 10, and is emitted outwards.Consequently, the light emission indicator of the icon is visually detected from a driver's eye point 36. In this case, compared to a case where the lens is formed from a thick plate with a combined size of the front plate 18a, the cavity 19, and the rear plate 18c, it is possible to reduce points of impact during forming and to reduce unevenness in the icon's light emission, since the front plate 18a and the rear plate 18c can be formed with a thin plate thickness. In particular, unevenness in light emission is likely to be noticeable because the triangular icon has a large light emission area. Thus, the effect of reducing unevenness in light emission is significant.Furthermore, it is possible to reduce the amount of light exiting cavity 19 and to use light efficiently for the light emission of the icon, since cavity 19 is formed in a pocket shape, with the left, right and bottom sides closed. Although in the lens of this embodiment the cavity is formed in a pocket shape, with the entire circumference of the cavity, except for the position of the opening through which light from the light source is introduced, being continuously surrounded by the coupling section, this does not constitute a limitation. That is to say, the cavity can be formed in a pocket shape, with a portion of the entire circumference of the cavity, except for the position of the opening through which light from the light source is introduced, being surrounded by the coupling section (e.g., by providing the coupling section discontinuously along the circumferential direction of the cavity, i.e., by dividing the coupling section and providing the partial coupling sections at multiple locations). Furthermore, the cavity need not necessarily be formed in a pocket shape.Furthermore, the location of the opening is not limited to the upper part surrounding the cavity. That is, the opening can be located on a side, a lower part, or similar area around the cavity. Additionally, a lens cut can be applied to the lens, or a reflective or coating film can be applied to the lens. Moreover, the lens color does not necessarily have to be white; it can be yellow or tinted in other colors. Although in the lens embodiment the front and rear plates are integrally coupled by the coupling section, this does not represent a limitation. That is to say, the front and rear plates can be formed from separate components and integrated into the BSM light emission unit. Although the lens of this embodiment does not have an additional light-transmitting element between the front surface of the front plate and the light-transmitting section that shapes the light into the icon shape, an additional light-transmitting element (e.g., an additional light-diffusing plate) can be arranged between them. Furthermore, the icon shape is not limited to a triangular shape. Moreover, the icon is not limited to being displayed on the mirror surface. Reference symbol list 10 Mirror plate 12 BSM (Blind Spot Monitor) light emission unit 12a Light emission surface (front face of front plate) 13 BSM (Blind Spot Monitor) light emitter 14 Housing 14a Front opening 14b Interior 14c Connector insertion port 14d Positioning hole 14f Nose mounting section 16 PCB (Printed Circuit Board) 18 Lens 18a Front plate 18a1 Front face of front plate (light emission surface) 18a2 Rear face of front plate 18c Rear plate 18c1 Front face of rear plate 18c2 Rear face of rear plate 18c' Area on left and right side of rear plate 18d Coupling section 18e Opening 18f Rib 18g Protrusion 18h Cutaway section 18i Nose 19 Cavity 20 LED (Light source) 20a Optical axis 22 Connector 24 Translucent section 26 Reflective film 28 Double-sided adhesive tape 28a Window 30 Approximate position corresponding to the icon display position 34 Light emitted by the LED 36 Driver's eye point QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature US 2016 / 0209000 A1

[0002]

Claims

Lens for a blind-angle monitor, comprising: a front plate; a rear plate arranged facing a rear side of the front plate, with a cavity arranged between them; a coupling section integrally coupling the front plate and the rear plate around the cavity;and an opening that allows the cavity to communicate with an exterior space of the cavity, wherein the front plate is configured to have a transmittance and simultaneous scattering of light characteristic, the rear plate is configured such that a front face of the rear plate facing the front plate has a reflectance and simultaneous scattering of light characteristic, the opening is configured to allow the introduction of light from a predetermined light source into the cavity through the opening, and the lens is configured to allow the use of light from the light source, which is passed through the front plate from the rear of the front plate to a front face of the front plate, to emit light of an icon. Lens for a blind spot monitor according to claim 1, wherein the coupling section is configured to couple the front plate and the rear plate along a circumferential direction of the cavity, and the cavity is surrounded by the coupling section and is formed in a pocket shape. Lens for a blind spot monitor according to claim 1, wherein the opening is formed between the front plate and the rear plate. Lens for a blind spot monitor according to claim 1, wherein the rear plate is arranged inclined relative to the front plate in the direction of the opening. Lens for a blind spot monitor according to claim 1, wherein the lens is made of an integrally formed article made of a turbid plastic material which has a characteristic of transmitting light and simultaneously scattering light. Blind spot monitor light emission unit, comprising: a light source;and a lens that receives light from the light source, transmits the light, and emits the light from a predetermined light-emitting surface, the lens comprising a front plate having the light-emitting surface, a rear plate facing a rear side of the front plate, with a cavity arranged between them, and an opening that allows the cavity to communicate with an exterior space of the cavity, the front plate being configured to have a transmitting and simultaneously scattering light characteristic, the rear plate being configured such that a front side of the rear plate facing the front plate has a reflecting and simultaneously scattering light characteristic, and light from the light source being arranged such that the light is introduced through the opening into the cavity. Blind-angle monitor light emitter comprising: a light source; a lens that receives light from the light source, transmits the light, and emits the light from a predetermined light-emitting surface; and a translucent section arranged in front of the light-emitting surface and forming a cross-sectional shape of light emitted from the light-emitting surface in a direction perpendicular to an optical axis into a predetermined icon shape, wherein the lens includes a front plate having the light-emitting surface, a rear plate facing a rear side of the front plate, with a cavity arranged between them, and an opening allowing the cavity to communicate with an exterior space of the cavity, the front plate being configured to have a transmittance and simultaneous scattering of light characteristic, and the rear plate being configured such thatthat a front side of the rear plate facing the front plate has a characteristic of reflecting and simultaneously scattering light, that light from the light source is arranged such that the light is introduced through the opening into the cavity, and that the light source is arranged in a position that is not visible through the translucent section when the light-emitting surface is viewed from a front.

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