JP5333110B2 - White LED device - Google Patents

Description

    The present invention relates to a white LED device excellent in color temperature and color rendering.

  Conventionally, as a white LED light source that outputs white light, by sealing a blue LED light source with a phosphor resin in which a yellow phosphor is dispersed, a mixed color of the emission color of the blue LED light source and the fluorescent color of the yellow phosphor can be obtained. What obtains white color is widely used (see, for example, Patent Document 1).

JP 2009-147312 A

However, the conventional white LED light source has a problem that the color temperature is high (for example, from 6000 K) to a bluish light color compared to the standard light, and the color rendering property is also poor (average color rendering index Ra = 70). .
This invention is made | formed in view of the situation mentioned above, and it aims at providing the white LED apparatus which radiates | emits white light excellent in color temperature and color rendering properties.

  In order to achieve the above-mentioned object, the present invention encloses a blue LED light source that emits blue light in a phosphor resin, and emits white light by mixing light emitted from the blue LED light source and fluorescence of the phosphor resin. A white LED unit in which a light source and a reflecting mirror are arranged to face each other; and a red LED light source that emits red light and a red LED unit in which a dichroic mirror is arranged to face each other, the red LED unit being the white LED unit The dichroic mirror of the red LED unit reflects the radiated light of the red LED light source and the wavelength of the radiated light of the red LED light source out of the radiated light of the white LED unit. Further, the present invention provides a white LED device characterized by transmitting a low wavelength.

  Further, the present invention is characterized in that the white LED device includes a controller that individually varies the light amount of the red LED unit or the light amounts of the red LED unit and the white LED unit.

According to the present invention, since the white light of the white LED unit is mixed with the red light of the red LED unit and emitted, the color temperature of the emitted light can be lowered by the red light. It can also improve sex.
In addition, since the white LED unit and the red LED unit are arranged in front and back so that the optical axes are aligned using a dichroic mirror, color unevenness and illuminance unevenness on the irradiated surface can be reduced.
In addition, when the radiated light of the white LED unit is transmitted through the dichroic mirror, the red wavelength region is cut, so that the color temperature of the transmitted light is increased, thereby mixing the light of the red LED unit with the transmitted light. Thus, the adjustment range of the color temperature of the light obtained can be widened.

It is a perspective view which shows the white LED apparatus which concerns on embodiment of this invention. It is the schematic of the side cross section of a white LED apparatus. It is a figure which shows typically the structure of the white LED light source with which a white LED unit is provided. It is a figure which shows the spectral distribution of a white LED light source with specific luminous efficiency. It is a figure which shows the spectral distribution of a white LED apparatus. It is a schematic diagram which shows the comparative structural example of a white LED apparatus. In a white LED light source and a comparison structure, it is a figure which shows the change of color temperature when the output of a white LED light source is maintained constant and the forward current of a red LED light source is varied. In a white LED light source and a comparison structure, it is a figure which shows the change of an average color rendering evaluation index | exponent when the output of a white LED light source is maintained constant and the forward current of a red LED light source is varied.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing the front and side surfaces of a stacked white LED device 1 according to this embodiment, and FIG. 2 is a schematic diagram of a side cross section thereof.
As shown in these drawings, the white LED device 1 includes a white LED unit 2 that emits white light and a red LED unit 3 that emits red light. The white LED unit 2 and the red LED unit 3 are The red LED units 3 are continuously arranged so that the optical axes are aligned along the light emission direction P with the red LED unit 3 at the head.
The configuration of the white LED unit 2 and the red LED unit 3 will be described. As shown in FIG. 2, each of the white LED unit 2 and the red LED unit 3 includes a cylindrical holder case 12 (or a cylindrical shape having a square cross section). The white LED device 1 is configured by being connected to each other via a connecting material 10. The holder case 12 is made of a metal material having high thermal conductivity such as aluminum, and a heat radiating portion 16 having a large number of heat radiating fins 14 is formed on the outer peripheral surface (outer surface) thereof.

The white LED unit 2 includes a white LED light source 4 that is a light source of white light, a lead frame 6 that supports the white LED light source 4, and a total reflection mirror 8 that is disposed so as to face the light emitting surface 4A of the white LED light source 4. ing. The lead frame 6 has the same configuration in each of the white LED unit 2 and the red LED unit 3, and as shown in FIG. 1, the annular portion 1A and a substantially circle arranged at the center O of the annular portion 1A. A plate-shaped attachment portion 1B and three arm portions 1C extending from the annular portion 1A toward the attachment portion 1B are provided, for example, die-molding a plate material having high thermal conductivity such as copper, for example. Are integrally formed.
On the back surface of the lead frame 6, the white LED light source 4 is fixed to the mounting portion 1B as shown in FIG. Further, as shown in FIG. 1, the arm portion 1 </ b> C is provided with a circuit board 18, and electric power from the outside is supplied to the white LED light source 4 through the circuit board 18. As shown in FIG. 2, the lead frame 6 is inserted into the holder case 12 through the rear opening 12A with the light emitting surface 4A of the white LED light source 4 facing the rear side, and is hooked on the hooking piece 12B.

  As shown in FIG. 2, the total reflection mirror 8 is inserted into the holder case 12 with a focal length adjustment spacer 20 interposed so that the optical reflection surface 8 </ b> A faces the light emitting surface 4 </ b> A of the white LED light source 4. The optical reflecting surface 8A has a reflection characteristic that totally reflects the radiated light of the white LED light source 4 arranged to face the parabolic surface (rotating parabolic surface) with the arrangement position of the white LED light source 4 as a focal point. Or it is formed in the aspherical surface. Therefore, the light emitted from the white LED light source 4 is reflected as light substantially parallel to the central axis (optical axis) N of the total reflection mirror 8, and the red LED unit ahead from the opening 12 </ b> D on the front side of the holder case 12. Radiated toward 3. The focal length adjusting spacer 20 compensates for the variation in the distance from the white LED light source 4 to the optical reflecting surface 8A caused by the manufacturing variation of the white LED light source 4, that is, the variation in the focal length f (see FIG. 2). The white LED unit 2 and the red LED unit 3 have the same light distribution characteristics and illuminance distribution.

The red LED unit 3 has substantially the same configuration as the white LED unit 2 except that a red LED light source 5 is provided instead of the white LED light source 4 and a dichroic mirror 9 is provided instead of the total reflection mirror 8. Is made.
The red LED light source 5 is an LED light source that emits light having a wavelength of 600 nm to 780 nm.
The dichroic mirror 9 reflects at least light in the wavelength band of the red LED light source 5 and has a shorter wavelength (for example, 600 nm) than the wavelength band of the red LED light source 5 in the white light of the white LED unit 2 incident from the back side. The following is a concave optical element that transmits light. That is, in this dichroic mirror 9, as shown in FIG. 2, the radiant light of the red LED light source 5 is reflected as parallel light along the central axis (optical axis) N and is incident from the back side. The two parallel lights are transmitted so as to be coaxially overlapped, and the mixed light M3 of the reflected light M2 and the transmitted light M1 by the dichroic mirror 9 is emitted from the white LED device 1 as white light.

  Further, as shown in FIG. 2, the white LED device 1 is provided with a controller 24 that individually adjusts the light amounts of the white LED unit 2 and the red LED unit 3.

FIG. 3 is a diagram schematically illustrating the configuration of the white LED light source 4 included in the white LED unit 2.
As shown in FIG. 3, the white LED light source 4 includes a light source body 30, one or a plurality of (one in the illustrated example) blue LED light sources 32, and two pairs of lead frames 34 that supply current to the blue LED light sources 32. And a phosphor resin 36 that covers the blue LED light source 32. The light source body 30 is provided with a concave cup 38 on its upper surface, and this cup 38 has a flat bottom portion 38A and a slope portion 38B having an inclination extending upward from the periphery thereof, and is formed in a trapezoidal shape in side view. Has been.

  The blue LED light source 32 is disposed substantially at the center of the bottom 38A of the cup 38, and the electrode of the blue LED light source 32 and the lead frame 34 are electrically connected by a wire (not shown). The blue LED light source 32 is sealed with the phosphor resin 36 made of resin in which a phosphor emitting blue fluorescence upon receiving blue light is dispersed. The phosphor resin 36 is further made of a substantially transparent transparent resin 40. The cup 38 is sealed. In the white LED light source 4, white light K <b> 3 is obtained by mixing the blue light K <b> 1 of the blue LED light source 32 and the yellow fluorescence K <b> 2 of the phosphor resin 36.

FIG. 4 is a diagram showing the spectral distribution of the white LED light source 4 together with the relative luminous efficiency. In the figure, the solid line A shows the spectral distribution curve and the solid line B shows the specific luminous curve.
Since the white LED light source 4 is configured to obtain the white light K3 by mixing the blue light K1 and the yellow fluorescent light K2, as shown by the solid line A, the white LED light source 4 has a wide wavelength band from 400 nm to 700 nm, but has a wavelength of 500 nm. The intensity at ˜700 nm is lower than the intensity at wavelengths of 400 nm to 500 nm. For this reason, the white light K3 has a relatively high color temperature and the emitted light is bluish light. Further, since the light amount becomes relatively low in the wavelength range of 500 nm to 700 nm, which is a region where the specific visual sensitivity is high, it is felt dark.

FIG. 5 is a diagram showing the spectral distribution of the white LED device 1.
In the white LED device 1, as described above, since the light of the red LED light source 5 is also added in addition to the white light of the white LED light source 4, the wavelength of 600 nm is generated by the light of the red LED light source 5 as shown in FIG. 5. Light with sufficient intensity can be obtained even in the above wavelength band. As a result, compared with the case where the white LED light source 4 is used alone, the color temperature becomes relatively low and approaches the standard light, and the amount of light in the region where the specific visual sensitivity is high increases, so that the white LED is felt bright. Compared with the case where the light source 4 is used alone, the color temperature and the brightness are improved.

  Here, since the white LED device 1 of the present embodiment is a stacked type in which the red LED unit 3 and the white LED unit 2 are stacked using the dichroic mirror 9, as shown in FIG. 6, the red LED light source S1 has a red color. Compared with the configuration (comparative configuration Q) in which the light L1 and the white light L2 of the white LED light source S2 are simply combined by the combining optical element T such as a prism to obtain the mixed light L3, there are the following advantages. .

FIG. 7 shows that in this embodiment (this configuration) and comparative configuration Q, the outputs of the white LED light sources 4 and S2 are kept constant, and the forward current (light quantity) of the red LED light sources 5 and S1 is 0 to 500 (mA). It is a figure which shows the change of color temperature when making it vary between.
In the comparative configuration Q, since the mixed light L3 is obtained by simply mixing the red light L1 and the white light L2, the red light component (light having a wavelength of 600 nm or more) of the white light L2 is not cut and mixed light is obtained. Included in L3. For this reason, even if the forward current of the red LED light source S1 is reduced and the red light L1 is reduced, the red component of the white light L2 exists, so that the maximum color temperature is compared as shown in FIG. It stays at about 6000-7000K without being too high.

  On the other hand, in this example, the dichroic mirror 9 cuts light with a wavelength of 600 nm or more from the white light of the white LED light source 4, so that the color temperature increases as the forward current of the red LED light source 5 decreases. It becomes higher than the comparative configuration Q, and the maximum value of the color temperature reaches about 14,000 to 15000K. Thus, in this example, there is an advantage that the adjustment range of the color temperature can be expanded as compared with the configuration in which the red light L1 and the white light L2 are simply combined to obtain the mixed light L3.

FIG. 8 shows that the outputs of the white LED light sources 4 and S2 are kept constant in the present embodiment (this configuration) and the comparative configuration Q, and the forward current (light quantity) of the red LED light sources 5 and S1 is 0 to 500 (mA). It is a figure which shows the change of the average color rendering evaluation index (Ra) when making it change between.
As shown in this figure, in this configuration, the average color rendering index Ra> 70 is obtained by adjusting the forward current of the red LED light source 5, and the color rendering property is higher than when the white LED light source 4 is used alone. It can be seen that the color rendering properties can be adjusted by changing the light quantity of the red LED unit 3. Further, as shown in FIG. 8, it can be seen that Ra> 70 in the range of up to 12000 K (forward current 50 mA or less) in this configuration having an enlarged color temperature of 6000 K or more (forward current 200 mA or less).

  Therefore, according to the use of the white LED device 1, the controller 24 can individually change the light amounts of the red LED unit 3 and the white LED unit 2 to realize the color temperature and color rendering according to the use. Can do. In particular, the white LED device 1 having a color temperature and color rendering suitable for use in medical illumination such as dental treatment can be obtained.

As described above, according to the present embodiment, the white light of the white LED unit 2 is mixed with the red light of the red LED unit 3, and thus the color temperature of the emitted light is adjusted by the red light. The color rendering property can be improved.
In addition, since the white LED unit 2 and the red LED unit 3 are arranged in front and back so as to align the optical axis using the dichroic mirror 9, uneven color and uneven illuminance on the irradiated surface can be reduced.
Further, since the red wavelength band of the radiated light of the white LED unit 2 is cut when passing through the dichroic mirror 9, the color temperature of the transmitted light M1 is increased, and thus the transmitted light M1 is converted into a red LED. The adjustment range of the color temperature of the mixed light M3 obtained by mixing the reflected light M2 of the unit 3 can be widened.

In addition, since the controller 24 is configured to individually change the light amounts of the red LED unit 3 and the white LED unit 2, each light amount can be controlled independently, and the color temperature and color rendering properties according to the application are realized. can do.
The controller 24 may be configured to adjust only the light amount of the red LED unit 3.

  The above-described embodiment is merely an aspect of the present invention, and it is needless to say that modifications and applications can be arbitrarily made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 White LED device 2 White LED unit 3 Red LED unit 4 White LED light source 5 Red LED light source 8 Total reflection mirror (reflection mirror)
9 Dichroic mirror 24 Controller 32 Blue LED light source 36 Phosphor resin N Central axis (optical axis)
P Light emission direction Q Comparison configuration

Claims (2)

A white LED in which a blue LED light source that emits blue light is sealed in a phosphor resin, and a white LED light source that emits white light by mixing light emission of the blue LED light source and fluorescence of the phosphor resin and a reflecting mirror are arranged opposite to each other Unit,
A red LED light source that emits red light and a red LED unit in which a dichroic mirror is disposed oppositely, and
The red LED unit is arranged with the optical axis aligned in front of the white LED unit,
The dichroic mirror of the red LED unit reflects the emitted light of the red LED light source and transmits a lower wavelength than the emitted light of the red LED light source among the emitted light of the white LED unit. White LED device.   The white LED device according to claim 1, further comprising a controller that individually varies a light amount of the red LED unit or a light amount of the red LED unit and the white LED unit.

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