JP2020013684A - Light emitting device including film light source - Google Patents

Abstract

To provide a light emitting device which includes a film light source whose light emitting efficiency is high and which does not impair a see-through property.SOLUTION: A light emitting device includes: a film light source 1 in which an LED chip (light emitting element)3 is disposed inside a translucent film 11, and which emits the light emitted in the LED chip 3 from both front and back surfaces of the translucent film 11; and a translucent back surface lens 2 integrated on the back surface of the film light source 1. The back surface lens 2 includes a translucent back surface step (optical step) 22 for internally reflecting the light emitted from the back surface of the film light source 1 toward the front surface side.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a light emitting device including a film light source having a light emitting element such as an LED (light emitting diode) mounted on a transparent film.

  A film light source in which an LED chip is laminated between two translucent films is provided, and it is considered to be applied to various light emitting devices, for example, a light emitting device for lighting or a sign of an automobile. Patent Document 1 proposes applying a light emitting device using the film light source to a high mount stop lamp of an automobile.

  In this type of film light source, the light emitted when the LED emits light is emitted from both sides of the film light source, so that the light emitting device is utilized by utilizing the light emitted from the front (one surface) of the film light source. When configured, it is difficult to effectively use the light emitted from the back surface (the other surface), and the overall luminous efficiency of the light emitting device is reduced.

  In Patent Document 1, a reflection surface is provided on the back side of a film light source, light emitted from the back surface is reflected by the reflection surface, and the reflected light is transmitted through a light-transmitting film of the film light source and emitted in the front direction. By doing so, the luminous efficiency is increased.

JP 2013-214492 A

  If a reflection surface is provided on the back side of the film light source as in Patent Literature 1, when the film light source is observed from the front side and the back side, the transparency of the film light source is lost due to the reflection surface. Patent Literature 1 proposes that the reflection surface is formed by a half mirror. However, even in this case, it is inevitable that the transparency is impaired due to a decrease in light transmittance. Therefore, when such a light emitting device is arranged in a rear window of an automobile as in Patent Literature 1 to form a high-mount stop lamp, the rear view of the automobile in the rear window in a region where the reflection surface exists is provided. Performance is impaired, and a problem in safe driving occurs.

  An object of the present invention is to provide a light emitting device having a film light source that has high luminous efficiency and does not impair transparency.

  According to the present invention, a light-emitting element is provided inside a light-transmitting film, and a film light source that emits light emitted from the light-emitting element from both the front and back surfaces of the light-transmitting film; A light-transmitting rear lens, wherein the rear lens includes a light-transmitting optical step of internally reflecting light emitted from the back of the film light source toward the front side.

  In the present invention, it is preferable that the film light source and the back lens are adhered in a state where the light emitting element and the optical step maintain a predetermined positional relationship. Also, in the present invention, the optical step includes a back step formed on the back of the back lens and retroreflecting light incident from the front of the back lens. Preferably, the optical step includes a front step formed in front of the rear lens and converging light emitted from the film light source toward the rear step.

  According to the present invention, the light emitted from the film light source in the rear direction is reflected toward the front by the optical step provided on the rear lens, so that the luminous efficiency of the light emitting element can be increased. Further, since the optical step is translucent, the transparency of the light emitting device can be ensured.

1 is a rear view of an automobile including a high-mount stop lamp to which the present invention is applied. FIG. 2 is a schematic perspective view of a high-mount stop lamp. FIG. 3 is an enlarged cross-sectional view along the line III-III of FIG. 1 and an enlarged view of a main part thereof. FIG. 3 is a schematic optical path diagram of a high-mount stop lamp. FIG. 7 is a perspective view illustrating a preliminary operation of a method for manufacturing a light-emitting device. Sectional drawing explaining the operation | work which sticks a film light source and a back lens. Sectional drawing of the modification of the optical step in a back lens. FIG. 14 is a cross-sectional view of another modification of the optical step in the rear lens.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a rear view of an automobile in which the light emitting device of the present invention is applied to a high-mount stop lamp. The high-mount stop lamp HMSL is arranged in an upper region of the rear window glass RWG of the car CAR, and is configured to emit light and be turned on when a brake operation of the car is performed. Note that in this document, the front and back sides are referred to as the front side on the light emitting side of the light emitting device (high-mount stop lamp), and the opposite side is referred to as the back side.

  FIG. 2 is a schematic perspective view of the high-mount stop lamp HMSL viewed from an inner surface side of the rear window glass RWG. I have.

  FIG. 3 is an enlarged vertical sectional view taken along the line III-III of FIG. The high mount stop lamp HMSL has a film light source 1 and a back lens 2, which are integrated in the thickness direction. The film light source 1 has a laminated structure in which two light-transmitting films 11 are bonded together with a light-transmitting adhesive 12, and a plurality of LEDs that emit red light are provided between the light-transmitting films 11. The chips 3 are mounted in a state where the chips 3 are arranged in a plurality of rows in the vertical direction and the horizontal direction, respectively. 1 and 2 schematically show the arrangement of the LED chips 3.

  A power supply wiring 13 made of a transparent conductive film such as ITO (Indium Tin Oxide) is formed in a required pattern on each inner surface of the two light-transmitting films 11, that is, on a surface to be bonded. The power supply wiring 13 is electrically connected to the plurality of LED chips 3, and a part of the power supply wiring 13 is provided at one edge of the translucent film 11 shown in FIGS. The connector 14 is configured. The edge connector 14 can be connected to a power supply connector C provided on a wind sash or the like of a car CAR, and power is supplied to each of the LED chips 3 via the power supply connector C.

  The LED chip 3 is configured such that positive and negative electrodes 32 are formed on both side surfaces facing the two translucent films 11 respectively, and one side face sandwiched between these electrodes 32 is a light emitting surface 31 for emitting light. It has been. Each LED chip 3 is supplied with power via the power supply wiring 13, and when emitted by power supply, the light emitted from the light emitting surface 31 is directed to both sides of each translucent film 11, that is, both the front and back surfaces of the film light source 1. The light is emitted in the direction.

  The rear lens 2 is formed of a flexible translucent resin into a sheet having a required thickness, and the front and rear faces of the rear lens 2 are respectively opposed to the LED chips 3 at positions corresponding to the LED chips 3. In the figure, a front step 21 and a rear step 22 are integrally formed as a translucent optical step at a position facing the light emitting surface 31 of the LED chip 3.

  The front step 21 is formed as a convex lens having the light emitting surface 31 of the LED chip 3 as a focal point, and converts the light from the LED chip 3 emitted from the back of the film light source 1 into a substantially parallel light beam (light beam). To converge.

  The rear surface step 22 is formed in a conical shape having a vertex angle of approximately 90 degrees. The light converged in the front surface step 21 is totally reflected by the inner surface of the rear surface step 22 and is returned toward the film light source 1. Since this back step 22 is configured as a recursive step, it may be in the shape of a pyramid.

  The rear lens 2 is made of a translucent resin material having a predetermined refractive index so that the front step 21 and the rear step 22 respectively realize the convergence of the light and the total reflection on the inner surface. Alternatively, the back lens 2 may be made of glass formed in a predetermined shape in advance.

  The rear surface of the rear lens 2 is integrated with the rear surface of the film light source 1 by bonding with a translucent resin sheet 4. Here, the translucent resin sheet 4 is configured as a UV (ultraviolet) curable resin sheet, and a hole 41 is formed in a region where the front step 21 is formed. The hole 41 forms a gap corresponding to the height dimension of the front step 21 when the film light source 1 and the rear lens 2 are bonded, so that the front step 21 does not interfere with the rear surface of the film light source 1.

  In the high mount stop lamp HMSL having the above configuration, when emitted, the red light emitted from the light emitting surface 31 of the LED chip 3 is emitted from the front and back of the film light source 1 as schematically shown in FIG. You. The light emitted from the front is transmitted through the rear window glass RWG as it is and irradiated toward the rear of the automobile CAR.

  The light emitted from the rear surface of the film light source 1 is incident on the rear lens 2 in a divergent light state, and the incident light is converged by the front step 21 to become a parallel light beam. Further, this light is totally reflected by the internal reflection in the rear step 22, and is returned to the front side. Further, the light is transmitted through the film light source 1 from the back side to the front side, and is superimposed on the light emitted from the LED chip 3 toward the front side. Therefore, almost all of the light emitted from the LED chip 3 is irradiated toward the front direction, that is, toward the rear of the car CAR, and is configured as a high-mount stop lamp HMSL having high luminous efficiency.

  On the other hand, in the high-mount stop lamp HMSL, since the film light source 1 and the rear lens 2 which are constituent elements are both formed of a translucent member, the car CAR passes through the rear window glass RWG and the high-mount stop lamp HMSL. It is possible to see through between the inside and outside. In this case, although the field of view is blocked by the LED chip 3 at the place where the LED chip 3 is provided, the LED chip 3 has a very small size and hardly affects the transparency.

  Further, the front step 21 and the rear step 22 of the rear lens 2 are not configured as a light reflecting surface as in Patent Document 1 and have translucency, so that the high-mount stop lamp HMSL is moved from the front side. Alternatively, when viewed from the back side, the transparency is not impaired. In particular, as shown by the dashed optical path in FIG. 4, when the occupant M of the automobile visually recognizes the outside, the transparency is not impaired by the front step 21 or the rear step 22. Therefore, the occupant M can see the rear area of the vehicle through the high-mount stop lamp HMSL, that is, through the entire surface of the rear window glass RWG, which is preferable for confirming safety.

  A method for manufacturing the above-described light emitting device, here, the high mount stop lamp HMSL will be described. In the high mount stop lamp HMSL, as described above, the LED chip 3 provided on the film light source 1 and the front step 21 and the rear step 22 provided on the rear lens 2 are accurately positioned so that they are opposed to each other. It is required that they be integrated after they are aligned. In the description of this manufacturing method, this alignment will be mainly described. The description of the respective manufacturing methods of the film light source 1 and the back lens 2 is omitted here.

  First, as a preliminary operation, the film light source 1 is supported on the carrier sheet 6 as shown in FIG. In FIG. 5A, the carrier sheet 6 is formed of a flexible translucent plate material having a size larger than that of the film light source 1, and positioning holes 61 are formed at several places, here three places. It is opened in a state penetrating in the thickness direction. The surface of the carrier sheet 6 is coated with an adhesive having a low adhesive strength so that the film light source 1 can be adhered.

  The positioning sheet 5 is substantially the same size as the carrier sheet 6 and is formed of a plate member having some rigidity, and a positioning window 52 having the same shape as the planar shape of the film light source 1 penetrates in the plate thickness direction. It is open in the state. On one surface of the positioning sheet 5, that is, a surface facing the carrier sheet 6, positioning protrusions 51 are formed at positions corresponding to the positioning holes 61 of the carrier sheet 6.

  Then, the positioning sheet 5 is placed on the carrier sheet 6 with the adhesive side facing upward. At this time, the positioning sheet 5 is positioned with respect to the carrier sheet 6 by fitting the positioning projections 51 into the positioning holes 61.

  Next, the film light source 1 is placed in the positioning window 52 of the positioning sheet 5 with the back side facing upward. With this placement, the film light source 1 is positioned with respect to the positioning sheet 5 and also at the same time with respect to the carrier sheet 6. At this time, the film light source 1 is temporarily fixed to the carrier sheet 6 by the adhesive.

  Then, when the positioning sheet 5 is removed from the carrier sheet 6, only the film light source 1 is supported in a state of being placed at a predetermined position on the upper surface of the carrier sheet 6, as shown in FIG. Before or after removing the positioning sheet 5, the translucent resin sheet 4 is placed on the upper surface of the film light source 1, that is, on the rear surface, and this is temporarily bonded to the rear surface of the film light source 1.

  FIG. 6 is a longitudinal sectional view for explaining a method of integrating the film light source 1 with the back lens 2. As shown in FIG. 6A, a base 100 for supporting the rear lens 2 is provided as a manufacturing apparatus. The base 100 is provided with a recess 101 on the upper surface, and the rear lens 2 is placed in the recess 101 with the front face upward. The recess 101 has a flat shape corresponding to the outer shape of the back lens 2 and is formed into a curved shape convex upward. This curved surface shape is a shape corresponding to the curved surface of the rear window glass RWG. When the rear lens 2 is placed in the recess 101, the positioning of the rear lens 2 with respect to the base 100 is automatically performed.

  In addition, positioning pins 102 are erected on the upper surface of the base 100 at three places adjacent to the recess 101. The positioning pins 102 correspond to the positioning holes 61 provided in the carrier sheet 6, and can be fitted into the positioning holes 61.

  Next, the upper and lower surfaces of the carrier sheet 6 are turned upside down so that the film light source 1 faces downward, and is then lowered from above the base 100. Then, as shown in FIG. 6B, the positioning holes 61 of the carrier sheet 6 are fitted to the positioning pins 102 of the base 100. Thereby, the positioning of the carrier sheet 6 with respect to the base 100 is performed, and at the same time, the positioning of the film light source 1 with respect to the rear lens 2 is performed.

  Then, the rear surface of the film light source 1 is brought into close contact with the front surface of the rear lens 2, and UV light is projected from above the carrier sheet 6 while maintaining this state. As a result, the translucent resin sheet 4 interposed between the film light source 1 and the back lens 2 is cured, and the film light source 1 and the back lens 2 are bonded and integrated to manufacture the high mount stop lamp HMSL. You.

  As described above, according to this manufacturing method, the film light source 1 and the rear lens 2 can be integrated while maintaining a predetermined positional relationship, and among the light emitted from the LED chip 3, the light emitted to the rear side Can be suitably returned to the front side by the back lens 2.

  Here, in the embodiment described above, the front step 21 provided on the rear lens 2 is configured to protrude from the front of the rear lens 2, but as shown in FIG. May be provided with a concave portion 23, and a convex lens-shaped front step 21 may be formed in the concave portion 23. By doing so, there is no protrusion on the front surface of the rear lens 2, and when attaching the film light source 1, it is not necessary to provide an opening in the translucent resin sheet 4, and the manufacturing process is simplified. Will be possible. Further, the thickness of the rear lens 2 and the translucent resin sheet 4 can be reduced, and the light emitting device can be made thinner.

  Further, as shown in FIG. 7B, a concave portion 24 may be further provided on the rear surface of the rear lens 2, and a rear step 22 for retroreflection may be formed in the concave portion 24. Thus, the thickness of the back lens 2 can be further reduced, and the thickness of the light emitting device can be reduced. In addition, when the rear side of the light emitting device, that is, the high-mount stop lamp HMSL is configured as described above, it is possible to prevent the rear window glass RWG from being protruded by the rear side step 22 on the surface on the vehicle interior side.

  In the present invention, the rear step of the rear lens is not limited to the shape of the above-described embodiment, as long as the light incident from the front side is internally reflected toward the front side. For example, as shown in FIG. 8, a rear surface step 22A having a convex shape toward the front surface, that is, a concave curved surface shape as viewed from the rear surface is formed on the rear surface of the rear lens 2, and the incident light is internally reflected in a divergent state. You may do so. In this example, the light internally reflected at the rear step 22A is reflected again at another internal surface of the rear lens 2 and is finally directed to the front. When configured in this manner, the rear lens 2 does not need to be particularly formed with a front step.

  In the above description, an example in which the light emitting device of the present invention is applied to a high-mount stop lamp of an automobile has been described. However, the light emitting device may be configured as another sign lamp. Alternatively, it can be configured as an illumination lamp. In any case, by applying the light emitting device of the present invention to a portion where transparency is required, such as a vehicle window, the visibility between the inside and the outside of the vehicle is ensured, and the light emitting efficiency of the light emitting device is improved. be able to.

1 Film light source 2 Back lens 3 LED chip (light emitting element)
4 Translucent resin sheet 5 Alignment sheet 6 Carrier sheet 11 Translucent film 12 Translucent adhesive 13 Power supply wiring 21 Front step (optical step)
22 Back Step (Optical Step)
31 Light-emitting surface CAR Automobile (vehicle)
HMSL high mount stop lamp (light emitting device)
RWG rear window glass

Claims (7)

  A light-emitting element is provided inside the light-transmitting film, and a film light source that emits light emitted from the light-emitting element from both the front and back surfaces of the light-transmitting film is integrated with the rear surface of the film light source. A light-transmitting rear lens, wherein the rear lens includes a light-transmitting optical step of internally reflecting light emitted from the rear surface of the film light source toward the front side. Light emitting device.   The light emitting device according to claim 1, wherein the film light source and the rear lens are adhered in a state where the light emitting element and the optical step maintain a predetermined positional relationship.   The light emitting device according to claim 1, wherein the optical step includes a rear surface step formed on a rear surface of the rear lens and retroreflecting light incident from the front surface of the rear lens.   4. The light emitting device according to claim 3, wherein the optical step includes a front step formed in front of the rear lens and converging light emitted from the film light source toward the rear step. 5.   5. The film light source according to claim 3, wherein at least one of the rear step and the front step is disposed in a recess formed in the front or rear surface of the rear lens and does not project from the front or rear surface. Light emitting device provided.   The film light source includes two light-transmitting films attached to each other and a light-emitting element disposed between the light-transmitting films, and emits light emitted from the light-emitting element to the two light-transmitting films. A light emitting device comprising the film light source according to any one of claims 1 to 5, wherein the light emitting device is configured to emit light to the outside through the light source. The light emitting device according to any one of claims 1 to 6, further comprising a film light source disposed in a window of the vehicle with the front of the film light source facing the outside of the vehicle.

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