JPH07230024A - Led light emission guide member - Google Patents

Abstract

PURPOSE:To obtain the inexpensive member in simple structure which can have an LED mounted on a fitting substrate in a regular state without using a lead bend or an auxiliary fitting substrate and emit light efficiently in a desired direction by fixing the surface angle of an incidence surface or total reflecting surface as specified, and guiding incident light in the desired direction and making it reach a projection surface. CONSTITUTION:The guide member consists of the lead type LED 8 which is regularly stood and fitted to the fitting substrate 81 of a printed wiring board, a display panel which is fixed vertically at one end edge of the fitting substrate 81 and has a rectangular display window at a specific position, and a guide member 1 as a molding of carbonate resin which guides the light emitted by the LED 8 well efficiently. The guide member 1 is in an L shape and has a 45 deg. slanting secondary curved surface 51 as its bent back surface and a secondary curved surface 52 whose lower part is further slanted by alpha deg., and they are the total reflecting surface 3 and a reflecting surface 33 respectively. Light reflected by the reflecting surface 33 reaches nearly the same area as the area to which reflected light from the total reflecting surface 3 is guided to the projection surface 4 within a range of its radiation angle theta less than the specific angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED guide member for guiding light emitted from an LED in a desired direction. An electronic circuit device is configured by mounting components on a printed wiring board to form a circuit, and an LED (Light) is used as a light source to display the operating status of the device.
Emitting diodes may be mounted, and the light emission of this LED has directionality, and it is required to match this with the display direction.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional example of mounting various LEDs. In general, the LED 8 for display has a light-emitting element enclosed in a transparent thin tube case as shown in FIG. Light is not emitted in the end direction, and the lead 82 projects from the other end.

Due to its structure, the LED 8 is used by inserting a lead 82 into a mounting substrate 81, which is a printed wiring board, and connecting and fixing it. Normally, it is mounted as shown in FIG. 9 (a) or (b) by bending and mounting, and (a) emits light vertically to the mounting substrate 81, and (b) bends the lead 82 and emits light in parallel direction.

Further, as shown in FIG. 9 (c) for attaching the reinforcing tool and (d) its sectional view, the LED 8 is stored in the reinforcing tool 83 so as to perform positioning and firm fixing, and this reinforcing tool 83 is attached. A structure in which the mounting substrate 81 is fixed by screwing is also used.

Further, in each of the various examples described above, the LED 8 is a lead type component, but the surface mount type L shown in FIG. 9 (e) is used.
As shown in the side sectional view of ED mounting, LE of surface mount type
When D88 is used, LED88 is mounted and the guide member
Auxiliary mounting board 84 consisting of a printed wiring board with 19 bonded
Is fixed to the display panel 9, and the auxiliary mounting substrate 84 and the main printed wiring board 85 are connected by a cable 91 and a connector 92.

[0006]

However, in the structure in which the lead 82 of FIG. 9 (b) is bent and attached, the angle and position at the time of bending the lead must be regulated and the man-hours need to be added accordingly. Needed. The structure using the reinforcing tool 83 of FIG. 9C requires the reinforcing tool 83 and the work of fixing the reinforcing tool 83 to the mounting substrate 81. Further, in the case of FIG. 9 (e), not only the auxiliary mounting board 84 is required, but also the cable 91 and the connector 92 for connecting to the main printed wiring board 85 are required, which increases the material cost and the structure is complicated. Therefore, the number of assembling steps is extra. There were problems such as.

In view of the above problems, the present invention provides an LED
LED guide member that guides the light emitted from a desired direction,
To provide an LED light emitting guide member having a simple structure, which can mount an LED on a mounting board in a normal state without using lead bending or an auxiliary mounting board, and can efficiently emit light in a desired direction. With the goal.

[0008]

The above-described object is to achieve the above-mentioned objects with reference to FIGS.
As shown in [1], a guide member for guiding the light emitted from the LED in a desired direction, which is formed by molding a transparent plastic material having a large refractive index, and has an incident surface 2 on which the light emitted from the LED 8 is incident and an incident surface 2
At least one total reflection surface 3 that totally reflects light from the
And the emission surface 4 for emitting the reflected light, the surface angle of the incident surface 2 or the total reflection surface 3 is predetermined, and the incident light is guided in a desired direction to reach the emission surface 4. This is achieved by the guide member 1. [2] Furthermore, the total reflection surface 3 or the entrance surface 2 has a plurality of quadric surfaces.
It is also applicable to the LED light emitting guide member 1 in which 51 and 52 are joined at a predetermined angle α. [3] Further, it is also achieved by the LED light emitting guide member 1 in which the total reflection surface 3 or the incident surface 2 is a cubic curved surface 6. [4] It is also applicable to the LED light emitting guide member 1 in which the surface of the emission surface 4 is made a rough surface 41 for scattering light, or a light scattering member 42 is closely attached to the surface. [5] The LED light emitting guide member of the present invention, in which a plurality of the LED light emitting guide members 1 are arranged side by side and integrally molded, and used for a plurality of LEDs 8 to increase the illumination area or brightness.
Also achieved by 11. [6] Further, a hole-shaped recess 13 for fitting the LED 8 is provided,
The LED light emitting guide members 1 and 11 having the bottom surface of the concave portion 13 as the incident surface 2 are also applicable. [7] Further, the LED light emitting guide members 1 and 11 are provided with engaging protrusions 12 for positioning and fixing the mounting substrate 81 of the LEDs 8.
Also achieved by.

[0009]

As shown in the principle configuration diagram of FIG. 1 (a), the guide member 1 is arranged so as to face the incident surface 2 to the upper light emitting portion of the LED 8 erected on the mounting substrate 81, and the incident light from the incident surface 2 is arranged. Is totally reflected by the inclined total reflection surface 3 and deflected in a desired direction (in the drawing, it is deflected at right angles to the mounting substrate 81 in parallel).
Light is emitted from the emission surface 4.

In general, the light emission of the LED 8 has a directional characteristic example as shown in FIG. 1 (b), and spreads not only in the vertical direction (θ = 0 °) with respect to the surface of the mounting substrate 81 but also in a substantially conical shape (directivity). There is. Therefore, it is important to efficiently guide the light in consideration of light emitted from the light source in various directions.

On the other hand, the light traveling from the material A having a large refractive index to the material B having a small refractive index is totally reflected by the boundary surface when the incident angle at the boundary surface is larger than a specific angle (critical angle). That is, substance A
Of the material B to the substance B is n, the critical angle is i ₀ , and the incident angle is i
Then, sin i ₀ = 1 / n, i> i ₀ is the condition for total reflection.

As shown in the principle diagram of FIG. 1 (c), vertical light from the light source is θ3, and then it is deflected to the left / right (positive / negative) by θ2, θ4, and light having a large directivity of θ1, θ5 enters the incident surface 2. , The incident light spread θ ′ is sin θ ′ due to the high refractive index material
= 1 / n · sin θ, the incident angle to the total reflection surface 3
It is incident at i _{1 to} i ₅ .

If the incident angles i _{1 to} i ₅ are smaller than the total reflection critical angle i _0, no reflection occurs and the light is emitted from the guide member 1 to the outside. For example, the incident light of θ1 at the left end in the figure has an incident angle i _{1 with} respect to the reflecting surface 3 as shown by the dotted line, and when i ₁ <i _0, it is refracted to the outside at the emission angle r _{1 and is} emitted. Further, the incident lights of θ 2 to θ 5 shown in the figure have incident angles i _{2 to} i _{5 with} respect to the reflecting surface 3, and i _{2 to} i ₅ > i ₀ , the reflection angle r ₂
The light is totally reflected at ~ r ₅ (= i _{2 to} i ₅ ), and the reflected light is guided to the emission surface 4 in a desired direction and refracted and emitted from the emission surface 4 to the outside.

As described above, it is not preferable that a part of the incident light is refracted from the total reflection surface 3 without being reflected and is emitted to the outside, because the amount of emitted light is reduced accordingly and the leaked light affects other illuminated light. .

Therefore, if the total incident angle on the total reflection surface 3 is made larger than the critical angle, the total incident light will be totally reflected. For this reason, as shown in the figure, the reflecting surface 33 in the refracting region of the total reflecting surface 3 which is not reflected is further inclined by an angle α, and the incident angle i ₁ ′ =
By providing the inclination α so that i ₁ + α is larger than the critical angle i _0, total reflection is performed.

As described above, the area portion (reflection surface 33) where reflection is not performed is further inclined and totally reflected.
As shown in (d), the area of the incident surface 2 (incident surface 22) through which the area of the incident light without reflection passes is inclined by an angle α and refracted to an extra extent to further narrow the spread of the incident light. , The incident angle i ′ with respect to the total reflection surface 3 can also be totally reflected by setting i ′> i ₀ > i.

Although the light guide cross section in one emission surface including the emission surface 4 from the light source has been shown and described above, the light emission spreads in a conical shape and extends from the light source to the reflection surface intersecting the desired direction. One emission cross section of emitted light (vertical light θ3 in Fig. 1 (c))
Fig. 1 (e)
As shown in, the light is emitted symmetrically, is refracted at the incident surface 2 and is narrowed in its spread, and enters the light, and is reflected at the total reflection surface 3.
When the total reflection surface 3 is a flat surface as shown by the dotted line, the reflected light spreads radially, and when it is a concave curved surface as shown by the solid line in the drawing, the spread of the reflected light is suppressed to make parallel light or focused light. Although it is not shown, in the case of a convex curved surface, the radiation spread of reflected light can be further expanded.

As described above, the total reflection surface 3 and the reflection surface 33 shown in FIG. 1C are composed of the quadric surfaces 51 and 52 including flat surfaces, and are joined at the angle α. Similarly, the incident surface 2,22 in Fig. 1 (d)
Is composed of quadric surfaces 51 and 52 including planes and is joined at an angle α.

In the above, the reflecting surface 3 and the incident surface 2 are quadric surfaces.
Although the structure is such that the joints are made at the inclination angle α of 51, 52, as shown in FIG.
As shown in (a), by making the incident surface 2 a convex spherical cubic curved surface 6, it is possible to narrow the spread of incident light and obtain parallel light or focused light. It becomes easy to guide light in a desired direction by using No. 3.

Further, as shown in FIG. 2 (b), the incident surface 2 has a flat shape,
The total reflection surface 3 is formed as a cubic curved surface 6 having a concave curved surface so that incident light can be totally reflected and the spread of reflected light can be suppressed. As described above, by suppressing the spread of the incident light or the reflected light, it is possible to totally reflect the plurality of total reflection surfaces 3 and efficiently guide the light to the emission surface 4 at a desired position as shown in FIG. 2 (c). it can.

Further, as shown in FIG. 1 (c), by making the surface of the emitting surface 4 a rough surface 41 provided with unevenness, light scattering is caused and the entire surface of the emitting surface 4 is made uniform. Brightness and
A clear display is obtained.

Instead of the rough surface 41, a semi-transparent or opaque film-like or thin plate-like light-scattering member 42 mixed with a light-scattering material is used as the surface of the emission surface 4 as shown in FIG. 1 (d). The same uniform brightness effect on the entire surface can also be obtained by bringing the same into close contact with.

Further, by arranging a plurality of the above-mentioned LED light emitting guide members 1 side by side and integrally molding them to form a guide member 11 as shown in FIG. 3 (a), the emission surface 4 can be enlarged. By arranging the LED 8 and the LEDs 8 with a narrow interval, it is possible to increase the size of the emitting surface 4 and increase the brightness.

Further, the LED light emitting guide members 1, 11
As shown in the section AA of FIG. 3 (b), a hole-shaped recess 13 for inserting the LED 8 is provided, and the bottom surface of the recess 13 is configured to be the incident surface 2, thereby improving the positional accuracy of the LED 8. ,
And a fixed reinforcement is obtained.

Further, as shown in FIG. 3 (b), the mounting board
The engaging projection 12 provided at a predetermined position facing the 81
The guide member 11 can be accurately and firmly fixed to the mounting substrate 81 by fixing the insertion tip portion to the 81 by heating and deforming it.

Further, for the surface mount type LED 88 having a slightly wide directional characteristic, as shown in the sectional view of FIG. 3 (c),
The concave material 13 is a shallow hole, and the incident surface 2 thereof is a spherical cubic curved surface 6 to suppress the spread of incident light.

Thus, with the LED light emitting guide member of the present invention, the LED can be surely mounted on the mounting board in a normal state without using lead bending or an auxiliary mounting board, and moreover, the LED can efficiently emit light in a desired direction. It is possible to provide an inexpensive LED light emitting guide member having a simple structure.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in the drawings. Throughout the drawings, the same reference numerals denote the same objects. FIG. 4 shows a first embodiment of the present invention, (a) is a perspective view of the configuration, (b) is a sectional view taken along line BB, and FIG. 5 is a second embodiment of the present invention, (a) is a perspective view of the configuration. FIG. 6 (b) is a sectional view taken along the line CC, FIG. 6 shows a third embodiment of the present invention, FIG. 6 (a) is a configuration perspective view, FIG. 6 (b) is a sectional view taken along the line DD, and FIG. Four examples are shown, (a)
Is a configuration perspective view, (b) is an EE sectional view, FIG. 8 shows a fifth embodiment of the present invention, (a) is a configuration perspective view, and (b) is an FF sectional view.

An example of the directional characteristic of the light emission of the LED is shown in FIG.
As shown in (b), it emits light in a substantially conical shape and in the vertical direction (θ = 0)
Is the strongest in the center, and becomes weaker as it deviates from the vertical direction (when the angle becomes larger in the positive and negative directions in the figure), and the vertical angle is 40 ° (θ
Approximately 80% in the range of ± 20 °), 90% in the range of 60 ° (θ = ± 30 °)
The amount of light is above.

In the first embodiment, as shown in FIG.
A lead-type LED 8 that is normally installed upright on the mounting board 81 of the printed wiring board, a display panel 9 that is vertically fixed to one edge of the mounting board 81, and has a rectangular display window 93 at a predetermined position, and the LED 8 emits light. The guide member 1 is a molded product of a carbonate resin (refractive index n≈1.5 with air) that efficiently guides light at a right angle.

As shown in the sectional view of FIG. 4 (b), the guide member 1 has an L-shape, and the bent back surface is an inclined quadric surface 51 of 45 °, and the lower part of the illustrated part is Further, the quadric surfaces 52 inclined by α ° are the total reflection surface 3 and the reflection surface 33, respectively.

This is because the refractive index n = 1.5 and the total reflection condition sin.
From i ₀ = 1 / n = 0.6667, the critical angle i ₀ = 41.81 °, and the emission angle θ ₀ of the LED 8 emission at this time is 4.78 °. Therefore, the directivity of emission (radiation angle θ) is 4.78 to 0.
In the range of -90 °, total reflection is performed, and in the range of 90>θ> 4.78 °, the light is refracted without being reflected. Therefore, the refraction light emitting area of the total reflection surface 3 is further α so as to reflect to θ = 30 °. = 16.5 °
The reflecting surface 33 is inclined. As a result, θ = 30 °
The incident angle i of the total reflection surface 3 is i = 25.52 °, but actually the incident angle i of the reflection surface 33 is i ′ = i + α =
42.02 °> i ₀ and total reflection occurs. Further 30 °>θ> 4.78
Even if the angle is at ₀ °, the incident angle i ′> i _{0 with} respect to the reflecting surface 33 is obtained and total reflection is performed.

In the above, the range of θ = ± 30 °, that is, 90% or more of the total amount of emitted light is guided to the emission surface 4, but θ = ±
At 20 °, total reflection can be done at α = 10 °, and about 80% can be guided. Of course, if θ is smaller than that, α is also small and total reflection occurs.

In any case, the totally reflected light from the reflecting surface 33 reaches substantially the same area where the light reflected by the totally reflecting surface 3 is guided to the emission surface 4 at θ <4.78 °. Further, the emission surface 4 has a rough surface 41 having fine irregularities, and causes light to be totally reflected and guided to reach the emission surface 4 to cause light scattering, so that the entire surface is evenly illuminated with uniform brightness. I am letting you.

Further, the guide member 1 is provided with a plurality of pin-shaped engaging projections 12 projecting from the surface of the LED 8 with respect to the mounting substrate 81 as a fixed surface, and the LED 8 is vertically inserted into the fixed surface. A recess 13 in the shape of a hole is provided, and the bottom surface of the recess 13 is integrally molded as a flat incident surface 2.
While fitting the LED 8 into the LED 13, the engaging projection 12 is inserted to the base of the fixing hole 86 provided in the mounting substrate 81 corresponding to the mounting position of the LED 8, and the mounting surface is brought into close contact with the engaging protrusion protruding on the opposite surface. The tip of the compound protrusion 12 is heated to prevent it from coming off and to be deformed and fixed.

The second embodiment is as shown in FIGS. 5 (a) and 5 (b). Explaining only the points different from those of the first embodiment, the total reflection surface 3-1 has a plane configuration inclined by 45 °. Instead, the part of the incident surface 2-1 (incident surface 22) in the area of the incident light that is not totally reflected is inclined by a predetermined angle α, and the convex quadric surfaces 51-1 and 52-1 are joined to each other. It is a thing.

The incident surface 2-1 has θ = 4.78 to 0 to −90 °
Range, the incident surface 22 is made incident with incident light of θ = 4.78 to 90 °, and the inclination α of the incident surface 22 with respect to the incident surface 2-1 is θ =
Α = 25 ° for ± 20 °, α = for θ = ± 30 °
By setting the angle to 33.5 °, all the desired incident light can be reflected by the total reflection surface 3-1, and the spread of the reflected light can be suppressed to the minimum.

Further, the surface of the emitting surface 4 is not made to be a rough surface 41, but an opaque plastic thin plate light-scattering member 42 mixed with a light-scattering material is adhered to the surface so that the entire surface has uniform brightness. ing.

The third embodiment is as shown in FIGS. 6 (a) and 6 (b). Explaining only the points different from the first embodiment, the total reflection surface 3-2 is composed of the cubic curved surface 6. Therefore, as described in the first embodiment, the larger the range of the radiation angle θ of the incident light in the area where total reflection is not performed, the larger the inclination α of the reflecting surface 33 becomes.
Must be made large, which means that there is an optimum α value for each θ value, and an optimum curve can be obtained by plotting this, and this is also plotted for other radiation surfaces, and the cubic surface 6 can be obtained. obtain. Further, with respect to incident light of θ = 0 to −90 °, the total reflection surface 3-2 is formed into a curved surface so that the spread of the total reflection light is suppressed as compared with the flat surface.

The fourth embodiment is as shown in FIGS. 7 (a) and 7 (b). Explaining only the points different from the second embodiment, the incident surface 2-2 is a convex spherical cubic surface 6-. In the first embodiment, instead of the curved reflecting surface 3-2 of the third embodiment, the incident surface 2-2 is curved, and even if the total reflecting surface 3-1 is a flat surface, the spread of the totally reflected light is similarly increased. It can be suppressed as much as possible.

As shown in FIGS. 8 (a) and 8 (b), the fifth embodiment is an example in which a plurality of LEDs 8 are used and a plurality of total reflection surfaces 3 are used, and an emission surface 4 (illumination surface). Is required, and the light guide emission surface 4 is located at a low position, and the reflection of a plurality of total reflection surfaces 3 is repeatedly guided.

Although it is possible to guide light to an arbitrary position by performing reflection a plurality of times, the light guide distance becomes long, the spread of reflected light becomes large, and the light reaching the emission surface 4 decreases. In order to prevent the spread as much as possible, the incident surface 2-2 is a convex spherical surface, and the first total reflection surface 3-3 is a quadric surface 51-2 that is linear in the alignment direction. Of the reflected light that is substantially parallel to the vertical direction, and the second and third total reflection surfaces 3-1 are flat surfaces. However, if necessary, if these are also curved surfaces, the light reaching the emission surface 4 can be spread in a predetermined manner.

The above is an example of each embodiment, and the materials and the combination configuration of the surface shapes of the incident surface 2 and the total reflection surface 3 are not limited to the above. Although the above description has been made only for the lead type LED 8, the LED of the present invention
It is clear that the light emitting guide member can be applied to the surface mounting type LED 88 in exactly the same manner, and the description thereof has been omitted.

[0044]

As described above, with the LED light emitting guide member of the present invention, the LED can be reliably mounted on the mounting board in a normal state without using lead bending or an auxiliary mounting board, and the LED can efficiently emit light in a desired direction. Thus, an inexpensive LED light emitting guide member having a simple structure can be obtained, which greatly contributes to productivity.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention. (A) Principle configuration diagram (b) Example of LED light emitting directivity characteristic (c) Principle explanation diagram (1) (d) Principle explanation diagram (2) (e) Principle explanation diagram (Part 3)

FIG. 2 is another principle diagram of the present invention (a) Principle explanatory diagram (4) (b) Principle explanatory diagram (5) (c) Principle explanatory diagram (6)

FIG. 3 is another principle diagram of the present invention (a) Principle explanation diagram (No. 7) (b) AA sectional view (c) AA sectional view (surface-mount LED)

FIG. 4 is a first embodiment of the present invention (a) configuration perspective view (b) BB sectional view

FIG. 5: Second embodiment of the present invention (a) Configuration perspective view (b) CC sectional view

FIG. 6 is a perspective view showing the configuration of a third embodiment of the present invention (a) and a sectional view taken along line DD of FIG.

FIG. 7 is a fourth embodiment of the present invention (a) isometric view of the configuration (b) EE sectional view

FIG. 8 is a fifth embodiment of the present invention (a) isometric view of the configuration (b) FF sectional view

[Fig. 9] Conventional LED mounting example (a) Regular upright mounting (b) Lead bending mounting (c) Reinforcing tool mounting (d) Reinforcing tool mounting cross section (e) Surface mount LED mounting

[Explanation of symbols]

1,11,19 Guide member 2,22 Incident surface 3
Total reflection surface 4 Emission surface 6 Cubic surface 8,
88 LED 9 Display panel 12 Engagement protrusion 13
Recess 33 Reflective surface 41 Rough surface 42
Light scattering member 51,52 Quadric surface 81 Mounting board 82
Lead 83 Reinforcement 84 Auxiliary mounting board 85
Main printed wiring board 86 Fixing hole 91 Cable 92
Connector 93 Display window

Claims (7)

[Claims] 1. A guide member for guiding light emitted from an LED in a desired direction, which is formed by molding a transparent plastic material having a large refractive index.
An incident surface (2) on which the light emitted from the ED (8) is incident, and the incident surface
(2) At least one total reflection surface that totally reflects the light from
(3) and an emission surface (4) for emitting reflected light, and guides the incident light in a desired direction by setting a predetermined surface angle of the incident surface (2) or the total reflection surface (3) An LED light emitting guide member characterized in that it reaches the surface (4). 2. The total reflection surface (3) or the incidence surface (2) is formed by joining a plurality of quadric surfaces (51, 52) at a predetermined angle (θ). LED light emitting guide member. 3. A total reflection surface (3) or an entrance surface (2) is a cubic curved surface.
(6) The LED according to claim 1, characterized in that
Luminescent guide member. 4. A rough surface (4) for scattering light on the surface of the exit surface (4).
The LED light emitting guide member according to claim 1, wherein the LED light emitting guide member is formed as described in 1) or has a light scattering member (42) closely attached to the surface thereof. 5. A plurality of LEDs are formed by arranging a plurality of LED light emitting guide members (1) according to any one of claims 1 to 5 side by side and integrally molding them.
An LED light emitting guide member for use in (8), which enlarges the area or brightness of the emission surface (4). 6. A hole-shaped recess (13) for accommodating an LED (8).
7. The LED light emitting guide member according to claim 1 or 6, characterized in that the bottom surface of the recess (13) is used as the incident surface (2). 7. The LED light emitting guide member according to claim 1, further comprising an engaging protrusion (12) for positioning and fixing the mounting substrate (81) of the LED (8).