CN1172040A

CN1172040A - Light emitting device

Info

Publication number: CN1172040A
Application number: CN97114637A
Authority: CN
Inventors: 金容济
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1996-07-10
Filing date: 1997-07-09
Publication date: 1998-02-04
Also published as: KR980010962A; KR0172327B1

Abstract

The present invention provides a light emitting device comprising a photoconductor. The photoconductor has an end coupled with a light source and the other points to a target. The photoconductor also comprises inner reflection surface reflecting light from the light source to the target. In an embodiment, the photoconductor is made of crylic resin, and the opposite surface exposes to air. The reflection surface slants to make the light from the light source entering the surface with an angle of incidence basically equal to or more than Theta shown in following formula, wherein Eta[air] represents refractive index of the air, Eta[air] represents refractive index of the crylic resin. Thus the light entering the surface is reflected to the target completely.

Description

Luminescent device

The present invention relates to luminescent device, relate to more precisely adopt optical conductor with light from the lead luminescent device of required direction of light source.

In electronics or mechanical system, luminescent device is the back that illuminating device usually is used for button switch or indicating device, even so that can't see under the situation of button or indicating device to the user in that brightness of illumination is low, the user is maneuvering system rapidly and exactly also.

And, switch of mono-or indicating device usually just are not installed, but are settled a plurality of switches or indicating device adjacent one another are.The exemplary of this type systematic comprises button switch on car audio system panel, the Automobile instrument or the key on the telephone bandset keyboard.

In these cases, in order to reduce the number of part, light illuminates many targets usually, for example switch or indicating device, rather than only illuminate a target.

Fig. 1 shows an example of conventional luminescent device.

In the device of Fig. 1, propagate by the optical plate of generally making 2 by polypropylene board by the light of light source 11 emissions.Because the end face of optical plate 2 has carried out screen printing,, the window 4 of the light that a part is being propagated by print surface 3 be used as illumination light so leaking out.

The inconvenient part of conventional luminescent device is that the light intensity of being launched by each button or indicating device changes the direction of observation of button or indicating device according to the user.

In order to overcome the problems referred to above, the purpose of this invention is to provide a kind of luminescent device, its intensity and user are irrelevant to the direction of observation of target that luminescent device has been installed thereafter.

In order to achieve the above object, made a kind of luminescent device that is used for illumination target, it comprises: one is used for radiative light source; And an one end is coupled in light source and the targeted optical conductor of the other end; Optical conductor is wherein made by first material and is comprised an internal reflection surface, makes this face reflex to target from the light of light source, and wherein tossing about of this face filled with second material.

This face preferably tilts, and makes light from light source to be substantially equal to or to incide on this face greater than the angle of incidence of following formula:

θ = \arcsin (\frac{η_{2}}{η_{1}})

η wherein ₁Be the ratio of refraction of first material, η ₂It is the ratio of refraction of second material.

After with reference to accompanying drawing most preferred embodiment of the present invention being described in detail, it is more obvious that above-mentioned purpose of the present invention and advantage will become, in these accompanying drawings:

Fig. 1 is the section-drawing of conventional luminescent device;

Fig. 2 is the section-drawing according to luminescent device of the present invention;

Fig. 3 is the amplification profile of the C part among Fig. 2;

Fig. 4 shows according to the reflectogram on the reflecting surface of the present invention.

Shown in Fig. 2,3 and 4, the luminescent device of most preferred embodiment comprises a light source 11 and an optical conductor 12 that has internal reflection surface 13.

Optical conductor 12 make by acrylic resin and by air around.One end of optical conductor 12 is coupled in light source, and the other end points to a target of button switch or indicating device and so on.

In this embodiment of luminescent device, the end that a plurality of (rather than only one) optical conductor is aligned to each optical conductor is coupled in light source.But in Fig. 2, only show in these optical conductors.

Go forward side by side into the light of optical conductor 12 by light source 11 emissions, on reflecting surface 13, be reflected and definite object.At this moment, the degree of dip of reflecting surface 13 is decided to be and whole incident lights is reflected and without any this face of light transmission on reflecting surface 13.

The cirtical angle of total reflection in the present embodiment is following to be determined.

If critical angle is θ, Snell laws of refraction is pointed out:

Because the ratio of refraction of air is 1.00029, and polyacrylic ratio of refraction is 1.480, so critical angle θ is:

= \arcsin (\frac{1.00029}{1.480} \times 1)

So=42 ° 31 ', if angle of incidence more than or equal to 42 ° 31 ', then incident light on this surface by total internal reflection.But if angle of incidence be exactly 42 ° 31 ', then angle of reflection also be 42 ° 31 ', cause when the incident light along continuous straight runs is advanced shown in Fig. 2-4, reflected light is along a bevelled direction rather than vertically upward advance.Therefore, in the present embodiment, reflecting surface is made into that to make angle of incidence be 45 °, so that when the incident light along continuous straight runs was advanced, reflected light was vertically upward advanced.

However, in other embodiments of the invention, angle of incidence still is chosen as the arbitrary values beyond 45 °, if this value more than or equal to 42 ° 31 '.

Simultaneously, shown in Fig. 2 and 3,, a plurality of steps on reflecting surface, have been made in order to strengthen the characteristic of optical conductor.That is when acrylic resin was cast into optical conductor, in the process that optical conductor is cooled, optical conductor may shrink, and makes the reflecting surface unevenness.To shrink the reflectance characteristics cause and degenerate in order to alleviate, on reflecting surface, made step.

For the luminescent device that is specially adapted to car audio system, according to the inventor's experiment, the height of each step (being the distance between line 13a and the 13b) is preferably less than 1.3mm.

And the size and dimension of optical conductor is decided by its application.

Simultaneously, because a plurality of optical conductors (each is aligned to the target that photoconduction is different towards each other) are coupled in a light source, so a light source can be used to the several objects of throwing light on.

As mentioned above, according to the present invention, owing on reflecting surface, directly illuminated target by total internal reflection from the light of light source, so no matter the direction of user's position or user's object observing how, can both be seen target rapidly and exactly.

Invention has been described in conjunction with some specific embodiment, obviously, can make further modification for person skilled in the art, and all such modifications is included among the scope of claims.

Claims

1. one kind is used for the luminescent device of illumination target, and it comprises:

One is used for radiative light source; And

One end is coupled in above-mentioned light source and the other end points to the optical conductor of above-mentioned target;

Wherein above-mentioned optical conductor is made by first material and is comprised an internal reflection surface, makes above-mentioned will reflex to above-mentioned target from the light of above-mentioned light source, and

Wherein above-mentioned toss about is filled with second material.

2. the luminescent device of claim 1, wherein said face tilt become to make light from above-mentioned light source to be substantially equal to or to be incident on above-mentioned greater than the angle of incidence θ of following formula:

θ = \arcsin (\frac{η_{2}}{η_{1}})

η wherein ₁Be the ratio of refraction of above-mentioned first material, η ₂It is the ratio of refraction of above-mentioned second material.

3. the luminescent device of claim 2, wherein said first material is made by acrylic resin, and above-mentioned second material is an air, and wherein said face tilt become make from the light of above-mentioned light source be substantially equal to or greater than 42 ° 31 ' angle of incidence and be incident on above-mentioned.

4. the luminescent device of claim 3, wherein said face tilt become to make from the light of above-mentioned light source and are incident on above-mentioned with 45 ° angle of incidence.

5. the luminescent device of claim 1, wherein said face comprises a step at least.

6. the luminescent device of claim 5, wherein the height of each above-mentioned step is less than or equal to 1.3mm.