JP5285380B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device such as an indicator lamp or a lighting fixture, and more particularly to an elliptical light emitting device in which the brightness in the front direction is higher than the brightness in the side surface direction.

  For example, as shown in FIGS. 2 and 3 of Japanese Patent No. 3491534, a conventional indicator lamp is formed in a cylindrical shape as a whole, and a plurality of LEDs are arranged on a circular substrate accommodated therein. Are arranged on the circumference.

In this case, the light emitted from each LED is reflected by the corresponding reflecting mirror and then emitted to the outside, so that the lighting of the indicator lamp is visually recognized from the outside.
Japanese Patent No. 3491534 (see paragraph [0010] and FIGS. 2 and 3)

  By the way, recently, there is a demand for slimming of device parts in the industry. In that case, simply reducing the outer diameter of the conventional cylindrical indicator lamp reduces the visibility of the indicator lamp. Occurs.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a light-emitting device that has a slim external shape and can ensure visibility. . The present invention is also intended to provide an elliptical light emitting device in which the brightness in the front direction is higher than the brightness in the side direction.

The invention of claim 1 is a light emitting device having an arbitrary elliptical shape, wherein a plurality of light sources each composed of LEDs (light emitting diodes) are arranged along the elliptical shape, and the optical axis of the emitted light of each LED is set. together aligned in the direction orthogonal to the tangential direction of the elliptical shape, provided along the lens unit of the elliptical tubular shape a plurality of built-in LED in the elliptical shape, intensity in the minor axis direction before Symbol elliptical for each LED directivity characteristic curve of the converted value is equal bite others of like Nozomu Tokoro becomes a value larger than this per axial unit length of the light intensity of the sum in terms of value the long axis direction per axial length unit length of the sum of by the LED disposed at a predetermined position in the circumferential direction of the elliptical shape having the front direction brightness or brightness from the brightness of the side direction from the (short axis direction) (long axis direction) of the light emitting device have to

  According to the first aspect of the present invention, since the light emitting device has an elliptical shape, the thickness in the minor axis direction can be reduced, thereby making it possible to slim the whole. Moreover, in this case, the brightness per unit length when viewed from the wide front direction of the light emitting device (that is, the elliptical short axis direction) is from the narrow side surface direction (that is, the long axis direction). It is equal to the brightness per unit length when viewed or brighter than this. Thereby, sufficient brightness in the front direction of the light emitting device can be ensured, and visibility as the light emitting device can be ensured.

  According to a second aspect of the present invention, in the first aspect, each LED is disposed on at least one of the major axis and the minor axis of the elliptical shape, and the LED is disposed between these LEDs.

  According to a third aspect of the present invention, in the first aspect, the length of the minor axis of the elliptical shape is a, the length of the major axis is b, and the optical axis of the light emitted from the LED is at an angle θ with the minor axis of the ellipse. When the light intensity of the LED in the short axis direction is f (θ) and the light intensity of the LED in the long axis direction is f (90 ° −θ), Σf (θ) / b ≧ Σf (90 ° −θ ) / a.

  Claim 3 is a mathematical expression of the content of claim 1. To summarize the above formula, a / b ≧ Σf (90 ° −θ) / Σf (θ). Thus, if the shape of the ellipse is determined (that is, if a / b is given), the above equation becomes a function of only θ. On the other hand, the luminous intensity K of the LED in the direction that forms an angle θ with the optical axis is provided as a directional characteristic curve that is a function of θ by the manufacturer of the LED. Therefore, by using this directional characteristic curve, an LED having a luminous intensity K that satisfies the above equation is selected.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the light emitting device is an indicator lamp including at least one structure having an elliptical shape and a plurality of light sources.

  In this case, by making the indicator lamp into an elliptical shape, the thickness in the minor axis direction can be reduced, thereby making it possible to slim the whole. In addition, in this case, the brightness per unit length of the axial length when viewed from the wide front direction of the indicator lamp (that is, the minor axis direction of the ellipse) is reduced in the lateral direction (that is, the major axis direction). ) Is equal to or brighter than the brightness per unit length of the axial length as viewed from. Thereby, sufficient brightness in the front direction of the indicator lamp can be ensured, and the visibility as the indicator lamp can be ensured.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, each of the plurality of LEDs has a light intensity in a direction of 90 degrees with respect to the optical axis being zero.

As described above, according to the light-emitting device of the present invention, the light-emitting device having an elliptical shape can reduce the thickness in the minor axis direction, and thus can be slimmed down as a whole. . Moreover, in this case, the brightness per axial length unit length when viewed from the wide front direction of width of the light emitting device (i.e. the minor axis direction of the elliptical shape), the narrow lateral width (i.e. elliptical It is equal to or brighter than the brightness per unit length of the axial length when viewed from the (long axis direction). Thereby, sufficient brightness can be ensured in the front direction (short axis direction) of the light emitting device, and visibility as the light emitting device can be ensured.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 to 6 are diagrams for explaining an indicator lamp (light emitting device) according to an embodiment of the present invention. FIG. 1A is a front view of the indicator lamp according to an embodiment of the present invention. Fig. 2 (b) is a plan view thereof, Fig. 2 (a) is a side view of the indicator lamp (Fig. 1), Fig. 3 (b) is a plan view thereof, Fig. 3 is an exploded view of the indicator lamp, and Fig. 4 is an indicator lamp. FIG. 5 is a schematic view showing an example of a layout on a substrate of an LED (light emitting diode) built in the lens unit, and FIG. 6 forms an angle θ with the optical axis. It is a directivity characteristic curve figure of LED showing luminous intensity K of LED of a direction. Note that, here, an example of an LED as a light source will be described, but the present invention can also be applied to other light sources.

  As shown in FIG. 1 to FIG. 3, the indicator lamp 1 includes an elliptical cylindrical lens unit 2 containing a plurality of LEDs (described later), a stand 3 that supports the lens unit 2 from below, and an upper part of the lens unit 2. And an elliptical cylindrical cap 4 attached to the main body.

  The lens unit 2 includes a light emitting unit 2A that emits light emitted from an internal LED. The light emitting unit 2A is made of a resin member having translucency, and is colored, for example, so as to emit colored light such as red, blue, yellow, green, or white according to the use of the indicator lamp 1. .

  On the outer periphery of the lower portion of the lens unit 2, a cylindrical spacer 5 having an elliptical shape (that is, an elliptical cylindrical shape) is attached. Further, a circumferential groove is formed on the outer periphery of the upper portion of the lens unit 2, and a packing 6 is attached to the circumferential groove. The packing 6 tightly seals between the upper portion of the lens unit 2 and the cap 4 to prevent moisture from entering the indicator lamp from the outside.

  The stand 3 has an elliptical cylindrical lead holder portion 30 and a disc-like stand base portion 31 formed integrally therewith. A plurality of (here, four) through holes are formed at equal intervals on the circumference of the stand base portion 31, and mounting bolts 35 are inserted into these through holes, respectively. A plurality of lead wires 36 for applying a power supply voltage to each LED extend from the lower surface of the stand base portion 31. The upper portion of each lead wire 36 is held by the lead holder portion 30.

  Since the cap 4, the lens unit 2, the spacer 5, and the lead holder portion 30 of the indicator lamp 1 are all formed in an elliptic cylinder shape, the entire indicator lamp except the stand base portion 31 has an elliptic cylinder shape extending in the axial direction. Is formed. That is, the thickness w in the minor axis direction of the indicator lamp 1 having an elliptical cross section is smaller than the thickness W in the major axis direction (w <W), preferably, w: W = 2: 3. For example, w = 40 (mm) and W = 60 (mm) are set.

  The stand 3, the cap 4 and the spacer 5 are all made of a non-translucent resin member so that light emitted from the LED does not leak outside.

  As shown in FIG. 4, the lens unit 2 has a plurality of (here, eight) LEDs 20a mounted on the substantially elliptical plate-like substrate 20c along the outer periphery of the elliptical shape, and a plurality of lead fittings. A board unit 20 to which 20b is attached, and a latching protrusion 21a that is inserted and latched from below into a latching hole 20d formed in the center of the board 20c of the board unit 20, and supports the board 20c from below. And a lens unit 22 that accommodates the substrate unit 20 and the base unit 21.

  The lens body 22 has a light emitting portion 2A on the outer periphery of the central portion in the axial direction. In addition, a locking hole 22 a for locking the tip of the locking projection 21 a of the base unit 21 is formed in the upper center of the lens body 22. A spacer 5 is mounted on the outer periphery of the lower portion 22 b of the lens body 22.

Next, FIG. 5 shows a substantially elliptical plate-like substrate 20c taken out. In the figure, for convenience of explanation, the substrate 20c is shown as a plan view elliptic length b of the length a and the major axis A _L of the short axis A _S. Eight LEDs 20a are arranged on the outer peripheral edge of the substrate 20c. Of these LED, LEDs 20a ₁ and 20a ₂ on the short axis _{A S} are arranged, LEDs 20a ₃ and 20a ₄ are arranged on the major axis _{A L.} Further, between these four LEDs 20a ₁ , 20a ₂ , 20a ₃ , and 20a ₄ , LEDs 20a ₅ , 20a ₆ , 20a ₇ , and 20a ₈ are arranged at, for example, the midpoint of the outer circumference of the elliptical arc shape. In other words, in this case, the LEDs 20a _{1 to} 20a ₈ are arranged, for example, at regular intervals on the outer peripheral edge of the substrate 20c.

The optical axis of the emitted light of each LED is oriented in a direction perpendicular to the tangent drawn in an ellipse at the position where each LED is arranged. That is, as shown in FIG. 5, the optical axes of the emitted lights of the LEDs 20a ₁ and 20a ₂ coincide with the minor axis direction of the ellipse, and the optical axes of the emitted lights of the LEDs 20a ₃ and 20a ₄ are the major axes of the ellipse. It matches the direction. Further, the optical axes of the emitted lights of the LEDs 20a _{5 to} 20a _{8 form} an angle θ with respect to the minor axis direction of the ellipse. In other words, the optical axes of the emitted lights of the LEDs 20a _{5 to} 20a _{8 form} an angle (90 ° −θ) with respect to the major axis direction of the ellipse.

  Each LED has a directivity characteristic as shown in FIG. That is, the maximum luminous intensity K when θ = 0 ° is K = 1.0, and the luminous intensity K when θ = 90 ° is minimum and K = 0. In this directional characteristic curve diagram, the luminous intensity K is represented by the magnitude of luminous intensity when the maximum luminous intensity is 1, and is relative luminous intensity.

  In the example shown in FIG. 4, a plurality of irregularities are formed on the outer peripheral edge of the substrate 20 c and the outer peripheral edge does not form an accurate elliptical shape. On the other hand, a tangent line is drawn, and the optical axis of the emitted light of each LED is arranged in a direction orthogonal to the tangent line.

Further, in FIG. 5, the long axis brightness of each LED20a seen from _{A L} direction of the substrate 20c of the elliptical shape is equal to the brightness of each LED as viewed from the short axis _{A S} direction. That is, the brightness in the side surface direction (long axis direction) of the indicator lamp 1 is equal to the brightness in the front direction (short axis direction) .

More specifically, conversion value per unit length of the sum of the light intensity of each LED when viewed from the longitudinal axis A _L direction of the substrate 20c of the elliptical, the sum of light intensity of each LED when viewed from the short axis A _S direction It is equal to the converted value per unit length.

Mathematically expressing this, in FIG. 5, when the light intensity in the short axis direction of the LED is f (θ) and the light intensity in the long axis direction is f (90 ° −θ),
Σf (θ) / b = Σf (90 ° −θ) / a (1)
The following relational expression holds.

The LEDs 20a ₁ , 20a ₃ , 20a ₄ , 20a ₅ , and 20a ₈ can contribute to the brightness viewed from the short axis direction of the substrate 20c (that is, the front direction of the indicator lamp 1), and the long axis direction of the substrate 20c. It is the LEDs 20a ₁ , 20a ₂ , 20a ₃ , 20a ₅ , and 20a ₆ that can contribute to the brightness as seen from the side of the indicator lamp 1. Substituting the value of θ for each LED into equation (1), the following equation is obtained.

{F (0) + f (90 °) + f (90 °) + f (θ) + f (θ)} / b
= {F (90 °) + f (90 °) + f (0) + f (90 ° −θ) + f (90 ° −θ)} / a
Organize this,
{F (0) + 2f (90 °) + 2f (θ)} / b
= {2f (90 °) + f (0) + 2f (90 ° −θ)} / a (2)
It becomes.

Next, dividing both sides of the equation (2) by f (0), the following equation is obtained.
{F (0) / f (0) + 2f (90 °) / f (0) + 2f (θ) / f (0)} / b
= {2f (90 °) / f (0) + f (0) / f (0) + 2f (90 ° −θ) / f (0)} / a (3)

In the expression (3), each term including / f (0) represents the relative luminous intensity K. Now, rewriting the expression (3) using the relative luminous intensity K,
{K (0) + 2K (90 °) + 2K (θ)} / b
= {2K (90 °) + K (0) + 2K (90 ° −θ)} / a (4)
It becomes.

Here, as is clear from FIG. 6, K (0) = 1 and K (90 °) = 0, and when these values are substituted into the equation (4), the following equation is obtained.
{1 + 2K (θ)} / b = {1 + 2K (90 ° −θ)} / a
Organize this,
a / b = {1 + 2K (90 ° −θ)} / {1 + 2K (θ)} (5)

  What can be understood from the equation (5) is that if the shape of the ellipse is determined (that is, if a / b is given), the equation (5) becomes a function of only θ. On the other hand, the luminous intensity K of the LED in the direction that forms an angle θ with the optical axis is provided as a directional characteristic curve that is a function of θ by the LED manufacturer. Therefore, by using this directional characteristic curve, an LED having a luminous intensity K that satisfies the above equation is selected.

According to such a present Example, since the indicator lamp was made into the elliptical cylinder shape, the thickness of a short-axis direction can be made thin, and it becomes possible to make the whole slim. In addition, in this case, the brightness of each light source viewed from the major axis direction of the elliptical substrate is equal to the brightness of each light source viewed from the minor axis direction. The brightness in the thin side direction (major axis direction) is equal to the brightness in the thick front direction (minor axis direction) . Thereby, sufficient brightness can be ensured also in the lateral direction of the indicator lamp, and visibility as an indicator lamp can be ensured.

In this case, the brightness per unit length viewed from the side direction (major axis direction) of the indicator lamp is equal to the brightness per unit length viewed from the front direction (minor axis direction). Therefore, the visibility as an indicator light can be further improved.

  Since the cap 4, the lens unit 2, the spacer 5, and the lead holder portion 30 of the indicator lamp 1 are all formed in an elliptical cylinder shape, when assembling them, each component is positioned in the circumferential direction. It is only necessary to fit up and down, and no complicated positioning in the circumferential direction is required at the time of assembling, and assembling becomes easy. Further, this prevents the fitting portion of each component from being damaged or the lead fitting from being damaged during the assembly, thereby improving the reliability during the assembly.

  The indicator lamp configured as described above is used as an indicator lamp for various machine tools, semiconductor manufacturing apparatuses, and the like. In this case, if the front face of the indicator lamp to be attached is directed to the front face of the machine or device, the visibility of the indicator lamp is improved. Further, when slimming of the entire machine or device including the indicator light is required, the side surface of the indicator light may be directed to the front of the machine or device. In addition, since four through holes for inserting mounting bolts are formed at equal intervals on the circumference in the stand base portion 31 of the indicator lamp, the indicator lamp can be rotated by rotating the stand base portion 90 degrees. Can be easily changed.

In the above embodiment, an example is shown in which LED20a is disposed on both the short axis A _S and major axis A _L of the elliptical shape are disposed on the outer peripheral edge of the substrate 20c, the application of the present invention is to It is not limited. LED20a may be arranged only on the one of the short axis _{A S} or major axis _{A L} of the substrate 20c. Alternatively, LEDs 20a may not be disposed on the short axis _{A S} or major axis _{A L} of the substrate 20c, for example, the outer periphery of the elliptical arc shape in between the eight LEDs 20a ₁ through 20a ₈ shown in FIG. 5 You may make it arrange | position LED20a to each middle point of each.

  Moreover, in the said Example, although demonstrated taking the case of LED which has a directional characteristic as shown in FIG. 6, application of this invention is applicable similarly to LED which has other directional characteristics. 7 and 8 show other examples of directional characteristic curves of LEDs. FIG. 7 shows an example of an LED having a narrow directivity angle, and FIG. 8 shows an example of an LED having the maximum luminous intensity in the vicinity of θ = 25 °.

  In the present invention, each light source need only be arranged along an elliptical shape. In addition to the case where the light sources are arranged along the outer periphery of the elliptical substrate 2c as in the above-described embodiment, an elliptical substrate 2c is provided. Instead, the light source may be arranged in an elliptical shape inside the elliptical lens unit 2.

Moreover, since it is thought that there are many opportunities to look from the front direction rather than from the side direction of the indicator lamp which has an elliptical shape, in order to raise the visibility of a front direction more, from the front direction (short-axis direction) of a display lamp. The brightness may be made brighter than the brightness from the side surface direction (major axis direction) . Including this case, the above equation (1) is expressed as Σf (θ) / b ≧ Σf (90 ° −θ) / a (6)
It becomes.

  In addition, the light emitting device according to the present invention may be a lighting fixture in addition to the indicator lamp as in the above embodiment.

(A) is the front view of the indicator lamp by one Example of this invention, (b) is the top view. (A) is a side view of an indicator lamp (FIG. 1), (b) is the top view. It is an exploded view of an indicator lamp (FIG. 1). FIG. 2 is an exploded view showing an internal structure of a lens unit constituting the indicator lamp (FIG. 1). It is the schematic which shows an example of the layout on the board | substrate of LED incorporated in the lens unit (FIG. 4). It is a directivity characteristic curve diagram of LED showing the luminous intensity K of LED of the direction which makes an optical axis and angle (theta). It is a figure which shows the other example of the directional characteristic curve figure of LED showing the luminous intensity K of LED of the direction which makes an optical axis and angle (theta). It is a figure which shows the further another example of the directional characteristic curve figure of LED showing the luminous intensity K of LED of the direction which makes an optical axis and angle (theta).

1: Indicator lamp (light emitting device)

2: Lens unit 2A: Light emitting unit 20a, 20a _{1 to} 20a ₈ : LED (light source)
20c: substrate

A _S : Short axis A _L : Long axis

a: Length of short axis b: Length of long axis

θ: Angle formed by the optical axis of outgoing light and the minor axis of the ellipse
f (θ): Luminous intensity K (θ): Relative luminous intensity

Claims (5)

A light emitting device having an arbitrary elliptical shape,
A plurality of light sources each consisting of LEDs are arranged along the elliptical shape, and the optical axis of the emitted light of each LED is oriented in a direction perpendicular to the tangential direction of the elliptical shape,
An elliptical cylindrical lens unit containing the plurality of LEDs is provided along the elliptical shape,
Converted value per axial length unit length of the light intensity of the summation in the minor axis direction is equal to bite the other and converted value per axial length unit length of the light intensity of the summation in the major axis direction before Symbol elliptical For each LED This side by an LED arranged in a predetermined position in the circumferential direction of the elliptical shape, the brightness from the front direction of the light-emitting device (short axis direction) having a directional characteristic curve of Nozomu Tokoro as to be greater than The brightness is higher than the brightness from the direction (long axis direction).
A light emitting device characterized by that. In claim 1,
Each LED is disposed on at least one of the elliptical long axis and short axis, and the LED is disposed between these LEDs.
A light emitting device characterized by that. In claim 1,
When the length of the short axis of the elliptical shape is a, the length of the long axis is b, and the optical axis of light emitted from the LED forms an angle θ with the short axis of the ellipse, the luminous intensity of the LED in the short axis direction Is f (θ), and the luminous intensity of the LED in the long axis direction is f (90 ° −θ),
Σf (θ) / b ≧ Σf (90 ° −θ) / a
The relational expression of
A light emitting device characterized by that. In any of claims 1 to 3,
The light emitting device is an indicator lamp including at least one structure having the elliptical shape and the plurality of light sources.
A light emitting device characterized by that. In any of claims 1 to 4,
Each of the plurality of LEDs has zero light intensity in a direction forming 90 degrees with respect to the optical axis.
A light emitting device characterized by that.

Images