JP2012169055A - Light guide member and fire detector using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide member, as well as a fire detector using the same, capable of shining a whole emission face by forming a light guide part thin to widen the light emission surface, and further, capable of making light efficiently emitted in any direction.SOLUTION: At one end of the light guide part 2 guiding light from a light-emitting element 5, an incident part 1 is provided for the light from the light-emitting element 5, while, at the other end, a reflecting part 3 for reflecting light passing the light guide part 2, and a light-emitting part 4 for emitting reflection light of the reflecting part 3 outside are provided. The reflecting part 3 is formed in a staircase pattern with first reflecting faces 30 slanted against an optical axis of light passing the light guide part 2 and second reflecting faces 31 parallel with the optical axis alternately arranged.

Description

  The present invention relates to a light guide member that guides light from a light emitting element, and a fire detector using the same.

  2. Description of the Related Art Conventionally, fire detectors that detect smoke generated during a fire in a building have been provided. This type of fire detector is generally installed on a ceiling or the like, and is generally provided with a light-emitting element for operation display that is turned on when the presence of smoke particles is detected, for example. In recent years, a planar light emitting diode chip having a planar light emitting surface has been adopted as a light emitting element for operation display so as to reduce the projecting dimension of the fire detector from the installation surface such as the ceiling. It has been proposed to surface mount a chip on a circuit board. A light guide member that is optically coupled to a planar light emitting element having such a planar light emitting surface and guides light from the light emitting element in a direction along the light emitting surface of the light emitting element, and the same are used. A fire detector is disclosed in Patent Document 1, for example.

  The light guide member is a molded product of a transparent synthetic resin, and at one end thereof, the light emitted forward from the light emitting surface of the light emitting element is collected to guide the light guide portion in the middle of the light guide member. A lens portion that guides light to the light guide portion and an introduction portion that guides light emitted laterally from the light emitting surface of the light emitting element to the light guide portion are integrally formed. That is, it has a shape that can increase the coupling efficiency with a surface-emitting light-emitting element having a planar light-emitting surface. In addition, a display unit that emits light guided through the light guide unit to the outside is formed at the other end of the light guide member, and the output surface of the display unit is the lower surface of the bottom wall of the body of the fire detector It comes to be aligned. Therefore, since the emission surface of the light guide member is exposed on the lower surface of the bottom wall of the body, the blinking state of the light emitting element can be visually recognized from the outside of the body.

JP 2003-248878 A

  However, in the light guide member having a uniform reflecting surface as in the above-described conventional example, the following problems occur. As shown in FIG. 7A, the light guide unit 101 having a thickness dimension of A1, the emission surface 103 having a width dimension of A2, and a predetermined angle with respect to the emission surface 103 (hereinafter referred to as “reflection surface angle”). Consider a light guide member 100 in which a reflecting portion 102 having a reflecting surface 104 inclined by θ is integrally formed. In this example, the light guide member 100 is used so that the longitudinal direction of the light guide portion 101 is parallel to the horizontal plane, and the width dimension A2 of the emission surface 103 is obtained by projecting the emission surface 103 onto the horizontal plane. Is the width dimension. In this light guide member 100, in order to emit the light reflected by the reflection surface 104 through the light guide unit 101 from the entire emission surface 103, the thickness dimension A1 of the light guide unit 101 and the width dimension of the emission surface 103 are used. The relationship of the following equation needs to be established with A2.

  FIG. 7B shows the result of calculating A1 / A2 when the reflection surface angle θ is changed using the above equation. As shown in the figure, in order to reduce the thickness dimension A1 of the light guide portion 101 while ensuring the width dimension A2 of the emission surface 103, the reflection surface angle θ must be reduced. That is, when the light guide member 100 is formed thin, the reflection surface angle θ is uniquely determined, and there is a problem that the angle (direction) of the emitted light cannot be arbitrarily set.

  Further, in the light guide member 200 as shown in FIG. 8A, the thickness dimension A1 of the light guide part 201 is smaller than the width dimension A2 of the exit surface 203 of the reflection part 202. Problems arise. That is, when the emission surface 203 is viewed in the direction of the arrow in the figure, the light reflected by the reflection surface 204 is emitted only from the region of the width dimension P1 on the emission surface 203, so that only the region is shining. (See FIG. 8B). Moreover, in this light guide member 200, since the intensity of the outgoing light in the direction perpendicular to the outgoing face 203 is increased, there arises a problem that the amount of light in the vertical direction is reduced.

  On the other hand, in the light guide member 300 in which the intermediate part of the light guide unit 301 is bent in the vertical direction as shown in FIG. 8C, the light reflected by the reflection surface 304 of the reflection unit 302 travels along the vertical direction. The light exits from the exit surface 303. In this light guide member 300, when the exit surface 303 is viewed in the direction of the arrow in the figure, the light reflected by the reflective surface 304 is a region having a width dimension P2 that is substantially the same as the width dimension A2 of the exit surface 303. Since the light is emitted from the light source, the whole light emission surface 303 appears to shine (see FIG. 8D). However, in the light guide member 300, the thickness dimension A1 of the light guide portion 301 is substantially the same as the width dimension A2 of the exit surface 303. For this reason, when the light guide member 300 is formed thin, the width dimension A2 of the emission surface 303 becomes small, and there arises a problem that the emission surface 303 cannot be widened.

  The present invention has been made in view of the above points. The light guide portion can be formed thin, and the light emission surface can be widened to shine the entire emission surface, and light can be efficiently emitted in any direction. It is an object of the present invention to provide a light guide member that can emit light and a fire detector using the same.

  The light guide member of the present invention includes a light guide part that guides light from the light emitting element, and an incident part into which light from the light emitting element is incident is provided at one end of the light guide part, The other end portion of the light guide portion is provided with a reflection portion that reflects light passing through the light guide portion and an emission portion that emits the reflected light of the reflection portion to the outside. The first reflection surface inclined with respect to the optical axis of the light passing through the portion and the second reflection surface parallel to the optical axis are formed in a step shape.

  In this light guide member, the relative refractive index of the material constituting the light guide member with respect to the outside air is n, the tilt angle of the first reflecting surface with respect to the optical axis is θ1, and the tilt angle of the emitting part with respect to the optical axis Is θ2 and the angle φ0 of the light emitted from the emitting portion with respect to the optical axis is

It is preferable to be determined based on

  In this light guide member, it is preferable that the emitting portion is processed so that emitted light is diffused.

  In the light guide member, it is preferable that the reflection portion has an acute angle with respect to the optical axis of the first reflection surface as the distance from the emission portion increases.

  In this light guide member, it is preferable that the width of the reflecting portion projected onto the optical axis of the first reflecting surface and the second reflecting surface becomes smaller as the distance from the optical axis increases.

  In this light guide member, it is preferable that the incident portion is formed of a convex curved surface protruding in a direction opposite to the light incident direction.

  In this light guide member, it is preferable that at least one or more other reflection parts that reflect light passing through the light guide part are provided between the incident part and the reflection part.

  A fire detector according to the present invention includes any one of the above light guide members and a housing that houses the light guide member, and the light emitting member of the light guide member is provided in the housing. It is exposed from the display hole and is disposed flush with the display hole.

  The present invention produces an effect that the light guide part can be formed thin, the light emission surface can be widened to make the whole emission surface shine, and light can be emitted efficiently in an arbitrary direction.

It is a figure which shows embodiment of the light guide member which concerns on this invention, (a) is schematic, (b) is an enlarged view of a reflection part. (A), (b) is a figure which shows the other structure of the incident part in a light guide member same as the above. It is explanatory drawing of the reflection part in a light guide member same as the above, (a) is an enlarged view, (b) is a figure which shows the various parameters with respect to the inclination-angle of a 1st reflective surface. It is a figure which shows the other structure of the reflection part in a light guide member same as the above. It is a figure which shows other structure of the reflection part in a light guide member same as the above. It is a figure which shows embodiment of the fire detector based on this invention, (a) is the top view seen from the lower side, (b) is a side view, (c) is the AA 'line cross section of (a). It is an arrow view. (A), (b) is a figure for demonstrating the problem in the conventional light-guide member. (A)-(d) is a figure for demonstrating the problem in the light guide member of the other structure of the past.

  Embodiments of a light guide member and a fire detector using the same according to the present invention will be described below with reference to the drawings. In the following description, the vertical direction in FIG. 1A is defined as the vertical direction. The light guide member LG1 of the present embodiment is a molded product of a transparent synthetic resin, and as shown in FIG. 1 (a), the incident portion 1, the light guide portion 2, the reflection portion 3, and the emission portion 4. Are integrally formed. A solid line B <b> 1 in the drawing indicates an optical path of light emitted from the light emitting element 5 and incident on the incident portion 1. Further, as the light emitting element 5, a planar light emitting diode chip having a planar light emitting surface is used as in the conventional example. Of course, the light emitting element 5 is not limited to this, and other light emitting elements may be used.

  In the following description, the light guide member LG1 is used so that the longitudinal direction of the light guide portion 2 is parallel to the horizontal plane, and the inclination angle θ1 of the first reflecting surface 30 to be described later with respect to the horizontal plane is set. Defined. That is, in this embodiment, the light passing through the central portion in the thickness direction of the light guide portion 2 is defined as the optical axis, and the angle and the like are defined with reference to the optical axis.

  As shown in FIG. 1A, the incident portion 1 is provided at one end portion (left end portion in the figure) of the light guide portion 2 and has a function of guiding the light emitted from the light emitting element 5 to the light guide portion 2. Have. In this embodiment, since it is assumed that the light incident from the incident portion 1 is parallel to the horizontal direction, the incident portion 1 has a simple configuration of a plane parallel to the vertical plane. Of course, as in the conventional example, the lens unit that condenses the light emitted from the light emitting surface of the light emitting element and guides the light to the light guide unit 2, and the light emitted from the light emitting surface of the light emitting element to the side. 2 may be integrally formed with the introduction portion leading to 2.

  Further, as shown in FIG. 2A, the incident portion 1 may be configured by a convex curved surface protruding outward (that is, opposite to the light incident direction) such as a convex cylindrical surface or a convex R surface. Good. In this case, since the incident portion 1 plays the same role as the convex lens, the light emitted from the light emitting element 5 and passed through the incident portion 1 becomes light substantially parallel to the horizontal direction. Therefore, since the light that has passed through the light guide unit 2 from the incident unit 1 is easily totally reflected by the reflection unit 3, the reflection efficiency can be improved.

  Further, as shown in FIG. 2B, the incident portion 1 may be configured from a reflection surface that reflects the light emitted from the light emitting element 5 and guides it to the light guide portion 2. In this case, if the inclination angle of the reflecting surface of the incident portion 1 is changed according to the direction of the light emitted from the light emitting element 5, the light guided to the light guide portion 2 can be made parallel to the horizontal direction. And the freedom degree of arrangement | positioning of the light emitting element 5 can be raised. In addition, when providing a reflective surface as mentioned above, it is not necessary to provide a reflective surface in the incident part 1 itself, and at least one or more other reflective parts are provided between the incident part 1 and the reflective part 3. Any configuration may be used.

  As shown in FIG. 1A, the light guide unit 2 is formed in a long and narrow plate shape whose longitudinal direction is parallel to the horizontal plane, and the light incident from the incident unit 1 provided at one end is connected to the other end (same as that shown in FIG. It has a function of leading to the reflecting portion 3 provided at the right end portion in the drawing. In addition, a protrusion 20 that protrudes upward is provided at an intermediate portion of the light guide 2. The protrusion 20 is fitted into a recess (not shown) provided in the housing 6 of the fire detector S1 when the light guide member LG1 is disposed in the fire detector S1 described later. This is a restricting means for restricting the movement of the light guide member LG1.

  As shown in FIG. 1A, the reflection unit 3 has a function of reflecting the light that has passed through the light guide unit 2 and guiding it to the emission unit 4. As shown in FIG. 1A, the emitting unit 4 has a function of emitting the light reflected by the reflecting unit 3 to the outside. The reflecting portion 3 is formed so that the width dimension A3 projected onto the horizontal plane is longer than the width dimension A2 projected onto the horizontal plane of the emitting section 4.

  And as shown in FIG.1 (b), the reflection part 3 alternately arrange | positions the 1st reflective surface 30 which inclines at a predetermined angle with respect to a horizontal surface, and the 2nd reflective surface 31 parallel to a horizontal surface. It is formed in a stepped shape. For this reason, the light from the light guide unit 2 is reflected by the reflecting unit 3 as compared with the case where the reflecting unit 3 is configured with a uniform plane (that is, only the first reflecting surface 30) (see the broken line in the figure). It can be reflected on the back side (right side in the figure) rather than the front side of 3 (left side in the figure). Therefore, in this embodiment, even if the thickness dimension A1 of the light guide part 2 is smaller than the width dimension A2 of the emission part 4 as compared with the case where the reflection part 3 is configured with a uniform plane, The entire part 4 can be illuminated.

  As described above, in the present embodiment, since the reflecting portion 3 is formed in a stepped shape in which the first reflecting surface 30 and the second reflecting surface 31 are alternately arranged, the light guide portion 2 is formed thin. The light emission surface (region where light is extracted at the emission part 4) can be widened to make the entire emission surface glow. In the present embodiment, as will be described later, by changing the inclination angle θ1 of the first reflecting surface 30 with respect to the horizontal plane and the inclination angle θ2 of the emission section 4 with respect to the horizontal plane, it is possible to arbitrarily illuminate the entire emission section 4. It is possible to emit light efficiently in the direction.

  By the way, the resolution of the human eye, that is, the minimum distance that can be identified as two distant points is about 0.3 mm when a human with a visual acuity of 1.0 is viewed at a distance of 1 m from the target. Therefore, it is desirable that the reflecting section 3 is formed so that the width of the first reflecting surface 30 and the second reflecting surface 31 projected onto the horizontal plane of each step is 0.3 mm or less. Forming the reflection part 3 in this way is preferable because light appears to be emitted uniformly from the emission part 4.

  Moreover, you may comprise so that the light radiate | emitted from the output part 4 may be diffused, for example by giving an uneven | corrugated process to the output part 4, forming an unevenness | corrugation, or sticking a light-diffusion sheet. This configuration is preferable because the light appears to be emitted uniformly from the emitting portion 4. Furthermore, since light is diffused by the emission part 4, visibility can be improved at a wider angle than when the emission part 4 is not processed.

  In the present embodiment, by appropriately setting the inclination angle θ1 of the first reflecting surface 30 with respect to the horizontal plane and the inclination angle θ2 of the emission part 4, the angle (hereinafter referred to as the horizontal direction) of the light emitted from the emission part 4 (Referred to as “emitted light angle”) can be set to an arbitrary angle. Hereinafter, a method for setting the emission angle φ0 will be described with reference to the drawings. In the following description, as shown in FIG. 3A, the incident angle of the light reflected by the reflecting portion 3 to the emission portion 4 is φ1, and the emission angle of the light from the emission portion 4 is φ2.

  The incident angle φ1 of the light reflected by the reflecting portion 3 to the emitting portion 4 is expressed by the following equation using the inclination angle θ1 of the first reflecting surface 30 and the inclination angle θ2 of the emitting portion 4.

  In addition, the light emission angle φ2 from the light emitting portion 4 includes the relative refractive index n with respect to the outside air of the material constituting the light guide member LG1, the inclination angle θ1 of the first reflecting surface 30, and the inclination angle θ2 of the light emission portion 4. And is expressed by the following equation.

  Here, the outgoing light angle φ0 is expressed by the following equation using the outgoing angle φ2 of the light from the outgoing portion 4 and the inclination angle θ2 of the outgoing portion 4.

  Therefore, the outgoing light angle φ0 is expressed by the following equation using the relative refractive index n of the material forming the light guide member LG1 with respect to the outside air, the inclination angle θ1 of the first reflecting surface 30, and the inclination angle θ2 of the emission part 4. It is represented by

  The outgoing light angle φ0 can be set to an arbitrary angle by appropriately setting the inclination angle θ1 of the first reflecting surface 30 and the inclination angle θ2 of the emission part 4 using the above equation. For example, let us consider a case where it is desired to set the outgoing light angle φ0 to 90 ° ± 15 ° (75 ° ≦ φ0 ≦ 105 °) with the inclination angle θ2 of the outgoing portion 4 being 18 degrees and the relative refractive index n being 1.49. In this case, as shown in FIG. 3B, the inclination angle θ1 of the first reflecting surface 30 may be set in the range of 37.1 ° ≦ θ1 ≦ 46.7 °.

  In addition, the reflection part 3 of this embodiment is formed in the step shape which arrange | positioned the 1st reflective surface 30 and the 2nd reflective surface 31 alternately, making inclination-angle (theta) 1 of the 1st reflective surface 30 constant. However, other configurations may be used. For example, as shown in FIG. 4, the inclination angle θ <b> 1 of the first reflecting surface 30 may be configured to become an acute angle as the distance from the emitting unit 4 increases. In this configuration, the light reflected by the reflecting portion 3 can be made substantially parallel to the vertical direction, so that the light can be uniformly emitted from the emitting portion 4.

  By the way, the light intensity of the light passing through the light guide 2 decreases as the distance from the optical axis increases. For this reason, a difference in light intensity occurs depending on the portion of the light reflected by the reflecting portion 3. Therefore, as shown in FIG. 5, as the distance from the optical axis increases, the first reflective surface 30 and the first reflective surface 30 are separated from the optical axis with reference to the width dimension L1 of the first reflective surface 30 and the second reflective surface 31 in the vicinity of the optical axis. It is desirable to reduce the width dimensions L2 and L3 of the second reflecting surface 31. In this configuration, since the reflection efficiency at the first reflection surface 30 and the second reflection surface 31 on which light with low light intensity is incident can be improved, the light from the portion where the light reflected by the reflection section 3 is reflected. The difference in intensity can be reduced, and light can be emitted uniformly from the emitting portion 4.

  Moreover, the light guide member LG1 of the present embodiment is used for, for example, a fire detector. Hereinafter, the fire detector S1 of this embodiment will be described with reference to the drawings. Note that the detailed structure and operation of the fire detector S1 are not the gist of the present invention, and thus the description thereof is omitted here. The fire detector S1 of the present embodiment is a photoelectric smoke detector attached to a ceiling or the like, and includes a housing 6 and a protective cover 7 as shown in FIGS.

  The housing 6 is formed in a shallow bottomed cylindrical shape whose upper surface side is opened by a synthetic resin, and has a cylindrical tube portion at the center of the bottom wall portion 60 bulging downward. The protective cover 7 is formed in a bottomed cylindrical shape that is open on the upper surface side by a synthetic resin, and is held in a cylindrical portion on the lower side of the housing 6 so that a smoke monitoring chamber (not shown) that monitors the intrusion of smoke. Is protecting.

  Inside the housing 6 is housed a circuit board 8 made of a printed circuit board on which circuit components constituting a light sensing element 5 and a smoke sensing circuit for judging the presence or absence of smoke are mounted. A light guide member LG <b> 1 is provided to guide light emitted from the light emitting element 5 mounted on the circuit board 8 to the outside of the housing 6. The light emitting element 5 is turned on and off by a smoke detecting circuit, and the light emitting element 5 is turned on when smoke is detected by the smoke detecting circuit.

  The emission part 4 of the light guide member LG1 is exposed from the display hole 61 provided in the bottom wall part 60 of the housing 6 and is disposed flush with the display hole 61. Therefore, since light is emitted outside from the entire display hole 61, visibility can be improved. Moreover, since the emission part 4 does not protrude from the display hole 61, a fire detector with excellent design can be provided.

DESCRIPTION OF SYMBOLS 1 Incident part 2 Light guide part 3 Reflection part 30 1st reflection surface 31 2nd reflection surface 4 Output part 5 Light emitting element LG1 Light guide body member

Claims (8)

  A light guide part for guiding light from the light emitting element is provided, and an incident part for receiving light from the light emitting element is provided at one end part of the light guide part, and the other end part of the light guide part is provided at the other end part of the light guide part. A reflection part that reflects light passing through the light guide part, and an emission part that emits the reflected light of the reflection part to the outside, wherein the reflection part is relative to the optical axis of the light passing through the light guide part A light guide member characterized by being formed in a staircase shape in which first reflective surfaces inclined and second reflective surfaces parallel to the optical axis are alternately arranged. The light emitting member has a relative refractive index n relative to the outside air, the inclination angle of the first reflecting surface with respect to the optical axis is θ1, and the inclination angle of the light emitting portion with respect to the optical axis is θ2. The angle φ0 of the light emitted from the optical axis is

The light guide member according to claim 1, wherein the light guide member is determined based on   3. The light guide member according to claim 1, wherein the emitting portion is processed so that emitted light is diffused. 4.   4. The light guide according to claim 1, wherein an angle of inclination of the first reflecting surface with respect to the optical axis becomes an acute angle as the distance from the emitting portion increases. 5. Element.   The width of the reflection portion projected onto the optical axis of the first reflection surface and the second reflection surface is reduced as the distance from the optical axis is increased. The light guide member according to Item 1.   6. The light guide member according to claim 1, wherein the incident portion includes a convex curved surface that protrudes in a direction opposite to a light incident direction.   The at least 1 or more other reflection part which reflects the light which passes the said light guide part is provided between the said incident part and the said reflection part, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. The light guide member described.   A light guide member according to any one of claims 1 to 7, and a housing that houses the light guide member, wherein the light emitting portion of the light guide member is provided in the housing. The fire detector is exposed from the display hole and is flush with the display hole.

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