JP2003248878A - Light guide member and fire sensor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide member which can efficiently converge and guide light from a plane light emission type light emitting element having a plane light emission surface, and to provide a fire sensor using the member. <P>SOLUTION: The fire sensor is equipped with the light emitting element 10 for operation display composed of a surface light emission type light emitting diode chip with a plane light emission surface which is mounted on a circuit board stored in a container body. The light from the light emitting element 10 is guided by the light guide member 20 and emitted to outside the container body. The light guide member 20 is a molding of transparent synthetic resin and characterized in that a lens part as a 1st incidence part functioning as a lens converging and guiding light emitted forward from the light emission surface of the light emitting element 10 to an intermediate light guide part 20a of the light guide member 20 and an introduction part 22 as a 2nd incidence part guiding light emitted sideways from the light emission surface of the light emitting element 10 to the light guide part 20a of the light guide member 20 are successively formed in one body. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide member for guiding light from a light emitting element and a fire detector using the light guide member.

[0002]

2. Description of the Related Art Conventionally, photoelectric smoke detectors utilizing the scattering of light by smoke particles have been provided as fire detectors for detecting smoke generated during a fire in a building. This type of fire detector is configured so that the light received from the light emitting element consisting of a light emitting diode element into the monitoring space is scattered by smoke particles and is received by a light receiving element consisting of a photodiode. If smoke particles exist in the space, the amount of light received by the light receiving element increases due to the generation of scattered light, so the presence or absence of smoke particles can be detected according to the amount of light received by the light receiving element.

By the way, a fire detector of this kind is generally installed on a ceiling or the like, and is generally provided with a light emitting element for operation display (operation confirmation) which is turned on when the presence of smoke particles is detected. As such a light emitting element, a light emitting diode element in which a transparent resin mold part covering the light emitting diode chip is molded into a shell shape and a pair of lead terminals is projected from the rear surface of the mold part is used. That is, as the light emitting element, the leaded insertion part has been used.

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 protruding size of the fire detector from the installation surface such as the ceiling. It has been proposed that the light emitting diode chip be surface-mounted on a printed circuit board. That is, it has been proposed to use surface mount components as the light emitting element.

[0005]

By the way, when a planar light emitting type light emitting diode chip is adopted as the light emitting element for operation display mounted on the circuit board as described above, the light from the light emitting surface of the light emitting diode chip is used. It is conceivable that the light is guided by a light guide unit in which individual lenses are combined and emitted outside the body. However, in the flat light emitting type light emitting diode chip having the flat light emitting surface as described above, since the emission angle is wider (wider directivity) than the light emitting diode element having the shell-shaped mold portion, The light guide means has a low light collection rate of light from the planar light emitting diode chip (that is, the coupling efficiency between the light emitting diode element and the light guide means is low), and the light output of light emitted outside the body is also provided. However, there is a problem in that the visibility deteriorates due to the deterioration of the visibility. Further, in order to increase the coupling efficiency between the planar light emitting diode chip and the light guide means, it is necessary to increase the size of each lens forming the light guide means.
Despite the use of the light emitting diode chip which can reduce the amount of protrusion from the circuit board as compared with the above light emitting diode element, there is a problem that the size of the fire detector protruding from the installation surface becomes large.

The present invention has been made in view of the above circumstances, and an object thereof is to guide light by efficiently condensing and guiding light from a planar light emitting element having a planar light emitting surface. The object is to provide a body member and a fire detector using the same.

[0007]

According to a first aspect of the present invention, light from a light emitting element is optically coupled to a surface emitting light emitting element having a planar light emitting surface in a direction along the light emitting surface of the light emitting element. A light guide member that guides light, the first incident portion introducing light emitted forward from the light emitting surface of the light emitting element, and the second incident portion introducing light emitted laterally from the light emitting surface of the light emitting element. An incident part is formed, and light emitted forward from a light emitting surface of a surface emitting type light emitting device having a planar light emitting surface is introduced from the first incident part and emits light. Since the light radiated laterally from the light emitting surface of the element is introduced from the second incident portion, it is possible to increase the amount of light incident from the light emitting element and efficiently collect the light from the light emitting element. Can guide light.

According to a second aspect of the present invention, in the first aspect of the invention, at least one of the first incident portion and the second incident portion functions as a lens for condensing light from the light emitting surface of the light emitting element. Therefore, the light incident from the light emitting element can be condensed so as to be totally reflected in the light guide member, and the reduction of the amount of light in the light guide member can be suppressed. It is possible to increase the amount of light emitted from the optical member.

According to a third aspect of the present invention, in the first aspect, the first incident portion has a curved incident surface that is convex toward the light emitting surface of the light emitting element, and light incident from the incident surface. Since it has a function as a prism having a reflection surface that changes the traveling direction so as to follow the light emitting surface, the light incident on the first incident portion can be obtained without increasing the number of components such as a mirror for changing the optical path. It is possible to change the traveling direction while suppressing the decrease in the light amount.

According to a fourth aspect of the present invention, a surface emitting light emitting element for operation display having a planar light emitting surface mounted on a circuit board housed in a body, and guiding light from the light emitting element. The light guide member according to claim 3, which is radiated to the outside of the body,
The light guide member is arranged such that the first incident portion faces the light emitting surface of the light emitting element and the second incident portion is closer to the light emitting surface than the first incident portion in the normal direction of the light emitting surface. The light of the surface emitting type light emitting element for operation display can be efficiently collected by the light guide member according to claim 3 and guided to be emitted outside the body. Therefore, it is possible to improve the visibility of the light emitted from the light guide member while reducing the thickness of the container.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) The fire detector in the present embodiment is a photoelectric smoke detector, and as shown in FIG. 5, it has a shallow bottomed cylindrical shape whose upper surface is opened by a synthetic resin. A body 1 having a cylindrical tubular portion 1b formed at the center of a bottom wall 1a formed and bulging downward, and a bottomed cylindrical body having an upper surface opened by a synthetic resin and held by the tubular portion 1b at the lower side of the body 1. Protective cover 2 and a light projecting element L which is housed in the protective cover 2 and includes a light emitting diode element on the lower surface side.
A circuit board 3 made of a printed circuit board on which a light receiving element PD made of D, a photodiode, and the like are mounted, and an optical base 4 which is made of synthetic resin and is formed in black and is accommodated below the circuit board 3 in the protective cover 2. A cylindrical labyrinth body 5 attached to the lower part of the optical base 4, a labyrinth cover 6 covering the lower side of the labyrinth body 5, and a cylindrical shape attached to the outside of the labyrinth body 5 inside the protective cover 2. An insect cover 7, a disk-shaped inner lid 8 made of synthetic resin and housed in the body 1, and a mounting base (not shown) fixed to a construction surface such as a ceiling surface and holding the body 1. I have it. The mounting base is made of a synthetic resin and has a shallow bottomed cylindrical shape with an opening on the lower surface side, and has an outer diameter substantially equal to the outer diameter of the upper end of the body 1. In addition, in the present embodiment, the mounting base, the body 1, and the protective cover 2 form a body.

The labyrinth body 5 has a large number of partition walls 5b each having a substantially horizontal horizontal cross section, and the adjacent partition walls 5 are adjacent to each other.
There is a smoke introduction path between b. That is, in the labyrinth body 5, one end of the smoke introduction path is opened to the outer surface to serve as a smoke introduction port, and the other end of the smoke introduction path is formed in the center of the labyrinth body 5 and has a circular horizontal cross section. It communicates with the room (monitoring space) S. Here, the partition wall 5b is made black so that light reflection does not occur, and the smoke introduction path is bent so that outside light is not introduced into the smoke monitoring chamber S.

On the other hand, the optical base 4 is formed with opening windows 4a and 4b respectively corresponding to the light projecting element LD and the light receiving element 2, and the light projecting element LD is fitted in the opening window 4a. Further, on the optical base 4, a light projecting lens 12 formed of a prism that guides the light emitted from the light projecting element LD to the smoke monitoring room S and the light in the smoke monitoring room S through the opening window 4b and the light receiving surface of the light receiving element PD. A light-receiving lens 13 formed of a prism for making the light incident on is held. Here, the light projecting element L
The optical axis of the light projecting unit configured by D and the light projecting lens 12 and the optical axis of the light receiving unit configured by the light receiving lens 13 and the light receiving element PD intersect in a plane including both optical axes. The circuit board 3 is connected to the upper end of the optical base 4.

A large number of windows 2b are formed in the peripheral wall of the protective cover 2 along the circumferential direction, and a large number of vent holes 7b, which are sufficiently smaller than the windows 2b, are formed in the insect cover 7 to prevent smoke. While allowing smoke to enter the sensing chamber, it is possible to prevent foreign matter such as insects from entering the smoke sensing chamber S. That is, smoke can enter the smoke monitoring chamber S inside the labyrinth body 5 through the window hole 2b and the ventilation hole 7b.

The outer diameter of the upper end of the protective cover 2 is substantially equal to the outer diameter of the lower end of the tubular portion 1b of the body 1,
Since the bottom wall 1a of the body 1 is formed with the drainage hole 1d which communicates with the inside and outside on the outer side of the cylindrical portion 1b, it is possible to prevent moisture from entering the inner side of the cylindrical portion 1b.

On the circuit board 3 described above, circuit components are mounted, which includes a light projecting element LD and a light receiving element PD, and which constitutes a smoke sensing circuit for determining the presence or absence of smoke based on the output of the light receiving element PD. Further, four terminal pins 9 for external connection project upward from the circuit board 3. Here, each terminal pin 9 is inserted into an insertion hole 8c penetrating the inner lid 8,
Are electrically connected to the four terminal plates 11 disposed on the upper surface of the. It should be noted that the above-mentioned mounting base is provided with a wire insertion hole (not shown) for inserting a wire from the ceiling, and the wire to be inserted into the body 1 through the wire insertion hole is attached to each terminal board 11. By connecting the wires, operation power is supplied to the smoke detection circuit, and the detection signal of the smoke detection circuit can be output to the outside.

Next, the operation will be described. Emitter L
The light from D is deflected by the light projecting lens 12 and is applied to the smoke sensing chamber S. When smoke enters the smoke monitoring chamber S, scattered light due to smoke particles passes through the light receiving lens 13 and the light receiving element PD.
The smoke sensing circuit can determine the presence or absence of smoke based on the output of the light receiving element PD.

By the way, on the upper surface of the peripheral portion of the circuit board 3,
A light emitting device 10 for operation display, which is a surface emitting light emitting diode chip having a planar light emitting surface, is surface-mounted. Lighting and extinguishing of the light emitting element 10 is controlled by a smoke detection circuit, and is turned on when smoke is detected by the smoke detection circuit. The light from the light emitting element 10 is stored in the body 1 and goes to the outside of the body 1 through an elongated plate-shaped light guide member 20 arranged along the radial direction of the body 1 in a plane parallel to the circuit board 3. It is supposed to be emitted. Here, the body 1 includes a light guide member 2 on the upper surface of the tubular portion 1b.
A mounting groove 1f into which one end portion of 0 is fitted is formed, and a display hole 1e into which the other end portion of the light guide member 20 is fitted is formed in the peripheral portion of the bottom wall 1a. In addition, a pair of position regulating ribs 1h are provided in the bottom wall 1a of the body 1 between the mounting groove 1f and the display hole 1e in the width direction of the light guide member 20 (see FIG. 5).
The protrusions are provided so as to be spaced apart from each other in the vertical direction in (b).
The amount of protrusion of each position regulating rib 1h from the bottom wall 1a is set so that the upper end edge of the position regulating rib 1h entirely contacts the inner lid 8, and has a function of supporting the inner lid 8 together with the tubular portion 1b. . Therefore, the middle portion of the light guide member 20 is housed in the space surrounded by the pair of position regulating ribs 1h, the bottom wall 1a and the inner lid 8, and the inner lid 8 is located between the tubular portion 1b of the body 1. In addition, it has a function as a holding plate that holds a part of the light guide member 20 and prevents the light guide member 20 from rising. Further, in the bottom wall 1a of the body 1, between the guide ribs 1h, a fitting hole 1e into which a hemispherical dowel 25 protruding from the lower surface of the light guide member 20 is fitted is provided. It is possible to regulate the movement of the optical body member 20 in the radial direction of the body 1.

The outer diameter of the inner lid 8 is set to be slightly smaller than the inner diameter of the body 1, and the inner lid 8 has a circular shape so that the upper end of the cylindrical portion 1b can be inserted into the central portion of the lower surface of the inner lid 8. A first recess 8a is formed on the lower surface of the inner lid 8, and a rectangular opening is formed on the lower surface of the inner lid 8 so that the upper end of each guide rib 1h and the upper end of the light guide member 20 can be inserted. The second recess 8b is formed, and the first recess 8a and the second recess 8b communicate with each other. Further, positioning projections 1c are provided at three locations on the peripheral portion of the bottom wall 1a of the body 1 so as to be spaced apart in the circumferential direction, and three positioning protrusions 1c are inserted on the peripheral portion of the inner lid 8 so as to be inserted therethrough. A hole (not shown) is provided therethrough.

By the way, the light guide member 20 is the light emitting element 1.
A light-emitting element 1 is a molded product of a transparent synthetic resin formed so as to guide light from 0 to the lower surface side of the body 1, and is optically coupled to a surface-emitting light-emitting element 10 having a planar light-emitting surface.
It has a function of causing light from 0 to enter from the one end and to exit from the other end. Therefore, the light guide member 2
0 has a function of guiding the light incident from the light emitting element 10 in the direction along the light emitting surface of the light emitting element 10 (that is, the radial direction of the body 1).

Here, as shown in FIGS. 1 and 2, the light guide member 20 collects the light emitted forward from the light emitting surface of the light emitting element 10 at the one end portion thereof. Two
A lens portion 21 having a function as a lens that guides the light guide portion 20a in the middle of 0, and an introduction portion that guides light emitted laterally from the light emitting surface of the light emitting element 10 to the light guide portion 20a of the light guide member 20. And 22 are formed. That is, the shape is such that the coupling efficiency with a surface-emitting light emitting element having a planar light emitting surface can be improved. In addition, the light guide member 20
Is formed at the other end thereof with a display section 24 for emitting the light guided through the light guide section 20a to the outside, and the emission surface 24a of the display section 24 is aligned with the lower surface of the bottom wall 1a of the body 1. It has become. Therefore, the exit surface 24 a of the light guide member 20
Is exposed on the lower surface of the bottom wall 1a of the body 1, so that the blinking state of the light emitting element 10 can be visually recognized from the outside of the body 1. In the present embodiment, the light emitting element 10 and the light guide member 20 constitute operation display means for displaying the operation state of the fire detector, and the emission section 24 of the light guide member 20 constitutes the display section. . Further, the lens part 21 constitutes a first incident part, and the introduction part 22 constitutes a second incident part.

The lens portion 21 of the light guide member 20 has an incident surface 21a on which the light emitted forward from the light emitting surface of the light emitting element 10 is incident, and the light which is incident through the incident surface 21a is reflected to advance the light. The light guide portion 2 has a function as a prism having a turning surface 21b that changes the direction to a direction along the light emitting surface.
0a is formed continuously and integrally. Here, the incident surface 21
a is formed in a curved surface shape that is convex on the light emitting surface side of the light emitting element 10, and the deflecting surface 21b is formed in a planar shape. 3 shows an optical path B of the light emitted from the light emitting element 10, and FIG. 4A shows an optical path B of the light incident from the incident surface 21a of the lens part 21. Introductory part 2 in b)
The optical path B of the light incident from the second incident surface 22a is shown. It can be seen from FIGS. 3 and 4 that the light incident from the light emitting element 10 is guided while being reflected by both surfaces in the thickness direction of the light guide portion 10a.

The introduction portion 22 of the light guide member 20 has an incident surface 22a on which the light radiated laterally from the light emitting surface of the light emitting element 10 is made incident, and is continuously formed integrally with the light guide portion 20a. There is. Here, the incident surface 22a is formed in a flat shape. Further, in the light guide member 2020, the lens portion 21 faces the light emitting surface of the light emitting element 10, and the introduction portion 22 is located closer to the light emitting surface of the light emitting element 10 than the lens portion 21 in the normal direction of the light emitting surface of the light emitting element 10. They are arranged so that they are close to each other.

Therefore, in the light guide member 20 of this embodiment, a surface emitting type light emitting diode chip having a planar light emitting surface and surface mounted on the circuit board 3 is adopted as the light emitting element 10 for operation display. However, since the elongated light guide member 20 that guides the light from the light emitting surface of the light emitting element 10 in the direction along the light emitting surface is provided, the mold part that covers the light emitting diode chip as the light emitting element 10 has a shell shape. The distance between the circuit board 3 and the inner lid 8 can be made smaller than in the case where a light emitting diode element that is molded and has the rear end portions of the pair of lead terminals protruding from the rear surface of the molded portion is used.

Moreover, the light radiated forward from the light emitting surface of the light emitting element 10 is guided to the one end of the light guiding member 20 facing the light emitting element 10 to the light guiding section 20a in the middle of the light guiding member 20. The light radiated laterally from the lens portion 21 and the light emitting surface of the light emitting element 10 is guided to the light guide portion 20 a of the light guide member 20.
Since the introduction portion 22 for guiding the light is formed, it is possible to enhance the coupling efficiency of light with the light emitting element 10 having a planar light emitting surface, and to reduce the amount of light entering the light guide member 20 from the light emitting element 10. Since it can be increased, the light output of the display unit 24 at the other end can be increased, and as a result, the visibility of the display unit 24 is improved. Further, since the lens portion 21 functions as a prism that changes the traveling direction of the light emitted forward from the light emitting element 10, an optical component (optical path changing auxiliary component) such as a mirror that reflects the light and changes the traveling direction of the light is used. It is not necessary to provide it separately, and it is possible to change the traveling direction of the light while suppressing the decrease in the amount of light, and the upper surface of the circuit board 3 (that is, The advantage that the distance between the mounting surface of the light emitting element 10) and the inner lid 8 that holds the light guide member 20 can be reduced, and the amount of protrusion from the ceiling surface of the fire detector can be reduced, and the number of parts are reduced. There are advantages such as a cost reduction and a cost reduction, and an advantage that the optical axis adjustment of the optical system is unnecessary and the assembling work is easy.

In each of the above embodiments, the incident surface 21a is
Is formed in a curved surface, it may be formed in a flat surface.

(Second Embodiment) The basic structure of the fire detector of the present embodiment is substantially the same as that of the first embodiment, and the light guide member 20 is used.
The shape is different. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

By the way, the fire detector needs to be regularly tested for operation, but as in the first embodiment, the light guide member 2 is used.
When the emission unit 24 of 0 is located on the peripheral portion of the bottom wall 1a of the body 1, the emission unit 24 may not be visible depending on the shape of the test device for the fire detector. That is,
Depending on the shape of the test apparatus, it is necessary to position the emitting portion 24 of the light guide member 20 near the central portion of the bottom wall 1a of the body 1 as in the fire detector of the present embodiment shown in FIG.

As shown in FIG. 6, the light guide member 20 in this embodiment is formed in an L shape, and the light traveling direction of the light emitting element 10 is emitted in the bent portion of the light guide member 20. A turning surface 23 is formed of a reflecting surface for turning the light emitting element 10 downward from the direction along the surface. A lens portion 21 and an introduction portion 22 having the same shape as those of the first embodiment are formed at one end of the light guide member 20. Further, FIG. 7 shows an optical path B of the light emitted from the light emitting element 10. It can be seen from FIG. 7 that the light incident from the light emitting element 10 is guided while being reflected on both surfaces in the thickness direction of the light guide portion 10a.

However, in the present embodiment, although the emitting portion 24 of the light guide member 20 is arranged close to the outer surface of the tubular portion 1b of the body 1 in accordance with the shape of the test apparatus, it has a planar shape. The light from the light emitting element 10 having the light emitting surface can be efficiently collected and emitted to the outside of the body 1.

In each of the above embodiments, the light guide member 2 is used.
Although a fire detector composed of a photoelectric smoke detector has been illustrated as a detector using 0, the light guide member 20 is not limited to a smoke detector, and a heat detector, a flame detector, a gas detector, and the like can be thinned. Can be used for various types of sensors that are desired.

[0032]

According to the first aspect of the present invention, a light guide element that is optically coupled to a surface emitting light emitting element having 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. The optical member includes a first incident portion that introduces light emitted forward from the light emitting surface of the light emitting element and a second incident portion that introduces light emitted laterally from the light emitting surface of the light emitting element. The light radiated forward from the light emitting surface of the surface emitting light emitting element having a planar light emitting surface is introduced from the first incident portion and radiated laterally from the light emitting surface of the light emitting element. Since the emitted light is introduced from the second incident portion, the amount of light incident from the light emitting element can be increased, and the light from the light emitting element can be efficiently condensed and guided.

According to a second aspect of the invention, in the first aspect of the invention, at least one of the first incident portion and the second incident portion functions as a lens for condensing light from the light emitting surface of the light emitting element. Therefore, the light incident from the light emitting element can be condensed so as to be totally reflected in the light guide member, and the reduction of the amount of light in the light guide member can be suppressed. There is an effect that it is possible to increase the amount of light emitted from the optical member.

According to a third aspect of the present invention, in the first aspect, the first incident portion has a curved incident surface that is convex toward the light emitting surface of the light emitting element, and a light incident from the incident surface. Since it has a function as a prism having a reflection surface that changes the traveling direction so as to follow the light emitting surface, the light incident on the first incident portion can be obtained without increasing the number of components such as a mirror for changing the optical path. There is an effect that the traveling direction can be changed while suppressing the decrease in the light amount.

According to a fourth aspect of the present invention, a surface-emitting light-emitting element for operation display having a planar light-emitting surface mounted on a circuit board housed in a body, and light from the light-emitting element are guided. The light guide member according to claim 3, which is radiated to the outside of the body,
The light guide member is arranged such that the first incident portion faces the light emitting surface of the light emitting element and the second incident portion is closer to the light emitting surface than the first incident portion in the normal direction of the light emitting surface. The light of the surface-emitting type light emitting element for operation display can be efficiently collected by the light guide member according to claim 3 and guided to be emitted outside the body. There is an effect that it is possible to improve the visibility of the light emitted from the light guide member while reducing the thickness.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of a fire detector according to a first embodiment.

2A and 2B show a positional relationship between a light guide member and a light emitting element used in the above, FIG. 2A is a front view and FIG. 2B is a bottom view.

FIG. 3 is an explanatory diagram of a waveguide path of light from a light emitting element in the light guide member used in the above.

FIG. 4 is an explanatory diagram of a waveguide path of light from the light emitting element in the light guide member used in the above.

FIG. 5 shows a fire detector according to the first embodiment, (a)
Is a cross-sectional view and (b) is a plan view with the inner lid removed.

6A and 6B show a positional relationship between a light guide member and a light emitting element used in the above, FIG. 6A is a front view, and FIG. 6B is a bottom view.

FIG. 7 is an explanatory diagram of a waveguide path of light from the light emitting element in the light guide member used in the above.

FIG. 8 shows a fire detector according to Embodiment 2, (a)
Is a cross-sectional view and (b) is a plan view with the inner lid removed.

[Explanation of symbols]

10 Light emitting element 20 Light guide member 20a light guide part 21 lens part 21a entrance surface 21b Deflection surface 22 Introduction 22a entrance surface 24 Outgoing part 24a exit surface

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoichi Oka             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F-term (reference) 2H038 AA52 AA54 BA42                 5C085 AA03 AB01 AC03 BA33 CA30                       DA07 DA08 FA06 FA40

Claims (4)

[Claims] 1. A light guide member which is optically coupled to a surface emitting light emitting element having 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. A first incident portion for introducing light emitted forward from the light emitting surface of the light emitting element and a second incident portion for introducing light emitted laterally from the light emitting surface of the light emitting element are formed. And a light guide member. 2. The at least one of the first incident part and the second incident part has a function as a lens for condensing light from the light emitting surface of the light emitting element. Light guide member. 3. The first incident portion has a curved incident surface that is convex toward the light emitting surface of the light emitting element, and a reflection that changes a traveling direction of light incident from the incident surface so as to follow the light emitting surface. The light guide member according to claim 1, having a function as a prism having a surface. 4. A surface-emitting light-emitting element for operation display, which has a planar light-emitting surface mounted on a circuit board housed in the body, and guides light from the light-emitting element to radiate it outside the body. The light guide member according to claim 3, wherein the light guide member has a first incident portion facing a light emitting surface of the light emitting element, and a second incident portion in a direction normal to the light emitting surface. A fire detector, wherein the fire detector is arranged so as to be closer to the light emitting surface than the light emitting surface.