JP2008205133A - Backlight device and color temperature adjustment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight device and color temperature adjustment method capable of adjusting the color temperature of white light formed by an LED and a phosphor. <P>SOLUTION: This backlight device and the color temperature adjustment method comprise a green LED 22 and a red LED 23 for adjusting the color temperature of the white light formed by a blue LED 21, and the phosphor which absorbs the blue light from the blue LED 21 and emits a light having a wavelength different from that of the blue light from the blue LED 21. The green LED 22 and the red LED 23 emit a light, having wavelengths different from that of the blue LED 21. Thus, this backlight device can adjust the color temperature of the white light, by adjusting the intensity of the light emitted from the green LED 22 and the red LED 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a backlight device for irradiating a liquid crystal panel with white light in a color liquid crystal display device.

  The color liquid crystal display device irradiates light generated by the backlight device from the back surface of the liquid crystal panel. The light from the backlight is transmitted through a module in which a liquid crystal panel and a color filter are combined, and a color image is displayed.

  Until now, CCFL (Cold Cathode Fluorescent Lamp) has been used as a light source constituting the backlight device.

  However, today, the light source of a backlight device used for a liquid crystal TV or the like is expected to be replaced from a CCFL to an LED (Light Emitting Diode).

  In general, when an LED is used as a light source of a backlight device, it is said that the lifetime, reliability, and performance are improved as compared with the case of using a CCFL.

Here, a general configuration of the color liquid crystal display device will be described with reference to FIG.
FIG. 10 is a schematic diagram showing a configuration of a general transmissive color liquid crystal display device.

  As shown in the figure, the transmissive color liquid crystal display device 100 includes a liquid crystal panel 101, a prism sheet 102, a diffusion sheet 103, a diffusion plate 104, and a backlight device 105. Here, the backlight device 105 includes a plurality of LED modules on which an LED is mounted on a wiring board, and generates white light by supplying a current to the LED (Light Emitting Diode).

  White light generated by the backlight device 105 is diffused by the diffusion sheet 103 and the diffusion plate 104, passes through the prism sheet 102, and is irradiated onto the liquid crystal panel 101.

  Next, a backlight device using LEDs will be described in more detail. First, as a prior art, there is a backlight device in which a light source of a backlight device is a combination of an LED and a phosphor that absorbs light emitted from the LED and converts wavelengths to emit light of different colors. This backlight device generates pseudo white light by the light emission of the LED and the phosphor.

  In this case, generally, an LED that emits blue light is used, and a phosphor that absorbs blue light and emits yellow light is used. A blue light emitting LED (hereinafter referred to as a blue LED) and a yellow light emitting phosphor (hereinafter referred to as a yellow phosphor) are combined to produce a pseudo white color (hereinafter referred to as a pseudo white color). It is used as the light source of the light device.

  However, the pseudo white color generated by the combination of the blue LED and the yellow phosphor as described above has few specific color components. In other words, in the case of the above-described mixed color of blue and yellow, red and There is a problem that the green component is small. Therefore, when pseudo white is used as a backlight for an LCD (Liquid Crystal Display), there is a problem that the color reproduction range is narrow, and further, the pseudo white has a problem of lack of color rendering. The color rendering properties indicate the luminance balance of the wavelength components of the light that constitutes white light.

  In addition, there is a method in which pseudo white is generated using phosphors of green light emission and red light emission instead of the yellow phosphor and used as a light source of the backlight device. In the case of this combination, the phosphor absorbs blue light from the blue LED and emits green light and red light. In other words, the phosphor emits light having a longer wavelength than the wavelength of the absorbed light. However, the light conversion efficiency deteriorates. In addition, although the color reproduction range is improved as compared with the case of using a phosphor emitting yellow light, there is a problem that the brightness of the generated white light becomes dark due to poor conversion efficiency.

  Patent Document 1 discloses an example in which a light source of a backlight device is configured by a blue LED, a red LED, an ultraviolet LED, and a phosphor that absorbs ultraviolet rays from the ultraviolet LED and emits green light.

  As shown in the example of Patent Document 1, white light irradiated on a liquid crystal panel is composed of light of three primary colors (blue, green, red), and light of the three primary colors is generated by individual LEDs. In some cases, the brightness of each light is adjusted by controlling the current value of each LED, and the above-described color temperature is adjusted.

  Further, Patent Document 2 proposes an example in which a blue LED, a red LED, and a green LED constitute a light source of a backlight device.

Similarly in Patent Document 2, the white light irradiated on the liquid crystal panel is generated by mixing light of three primary colors (blue, red, and green). Therefore, the color reproduction range is wide as compared with the pseudo white light generated by the blue LED and the yellow phosphor. Also, the variation in color temperature is adjusted by individually adjusting the brightness of the light of the three primary colors.
JP 2006-91896 (April 6, 2006) JP 2006-237282 (published September 7, 2006)

  However, the method of generating the light of the three primary colors constituting the white light irradiated to the liquid crystal panel as described above using individual LEDs for each color requires a large number of LEDs in the backlight device. . As a result, there arises a problem that the number of LEDs required for the backlight device increases and the cost increases.

  Specifically, assuming that a combination of one blue LED that generates white light and a yellow phosphor is one dot, the number of light sources required for a backlight device (directly-type) in a 46-inch transmissive liquid crystal display device Is about 700 dots.

  At this time, when white light is generated by a combination of a blue LED and a yellow phosphor, the number of LEDs necessary for the backlight device is 700 dots of 700 dots × blue LEDs. In addition, when white light is generated by a red LED, a blue LED, and a green LED, the number of LEDs required for the backlight device is 2100 from 700 dots × (red LED + blue LED + green LED). .

  As mentioned above, when white light is generated by three primary color LEDs (red LED + blue LED + green LED), the number of LED chips is three times as much as when white light is generated by blue LED and yellow phosphor. This increases the cost.

  Next, when a short wavelength LED and a plurality of phosphors are used, for example, problems in a backlight device using a blue LED, a red phosphor, and a green phosphor will be described.

  In the case of the above combination, since the number of LEDs required for constituting a one-dot light source is one of short wavelength LEDs, there is an advantage that the component cost is low. Furthermore, since the white light is generated by the three primary colors of blue light from the short wavelength LED and green light and red light from the green phosphor and red phosphor, the color reproduction range of white light is wide. Become.

  However, in the white light generated by combining the blue LED, the green phosphor, and the red phosphor as described above, the color reproduction range is fixed, and the color temperature of the generated white light cannot be adjusted. There is. This is because green light and red light constituting white light are generated by the phosphor, and the luminance of the light emitted from the phosphor depends on the luminance of the absorbed light, that is, in this case, from the blue LED. This is because it is determined by the luminance of blue light. Therefore, since the brightness of the light of the three primary colors cannot be individually adjusted, there arises a problem that the color temperature of the generated white light cannot be adjusted.

  The present invention has been made in view of the above-described problems, and an object thereof is a backlight device capable of adjusting the color temperature of white light generated by an LED and a phosphor, and luminance and color. And providing a temperature control method.

In order to solve the above problems, the backlight device of the present invention is
A backlight device comprising: a first light emitting diode; and a phosphor that absorbs light emitted from the first light emitting diode and emits light having a wavelength different from the absorbed light. At least one second light-emitting diode that adjusts the color temperature of white light generated from light from one light-emitting diode and the phosphor, and the second light-emitting diode includes the first light-emitting diode. It is characterized by emitting light having a wavelength different from that of light from the light emitting diode.

  With the above configuration, the backlight device causes the first light emitting diode to emit light by supplying current to the first light emitting diode. Further, the phosphor emits light emitted from the first light emitting diode, and emits light having a wavelength different from that of the first light emitting diode. White light generated by the backlight device is constituted by the light from the first light emitting diode and the phosphor.

  Here, since the phosphor absorbs light from the first light emitting diode and emits light, the luminance of the light emitted from the phosphor is determined by the luminance of the light from the first light emitting diode. Therefore, since the brightness of light from the first light emitting diode and the brightness of light from the phosphor cannot be individually adjusted, there is a problem that the color temperature of the generated white light cannot be adjusted.

  In order to solve this problem, the backlight device of the present invention includes at least one or more types of second light emitting diodes for adjusting the color temperature of white light generated by the first light emitting diodes and the phosphor. ing. The backlight device supplies a current to the second light emitting diode, and adjusts the current value so that the brightness of the light from the second light emitting diode is increased separately from the light from the first light emitting diode. Can be adjusted. The second light emitting diode emits light having a wavelength different from that of the first light emitting diode. Here, by adding the light from the second light emitting diode to the white light generated from the first light emitting diode and the phosphor, the balance of the wavelength components of the white light, in other words, the color temperature of the white light is adjusted. Will change.

  Therefore, the backlight device adds the light from the second light emitting diode to the white light generated from the light from the first light emitting diode and the phosphor, and further increases the luminance of the light from the second light emitting diode. By adjusting, the color temperature of white light generated in the backlight device can be adjusted.

The backlight device of the present invention further includes
The second light emitting diode is smaller in size than the first light emitting diode.

  First, the second light emitting diode is provided in the backlight device in order to adjust the luminance and color temperature of white light generated by the backlight device. Therefore, compared to the first light-emitting diode that emits the light that is the basis of white light, the luminance of the light emitted from the second light-emitting diode for each type is sufficient. Therefore, the backlight device can make the size of the second light emitting diode smaller than the size of the first light emitting diode.

  Here, in general, the price of the light emitting diode is lower as the size is smaller. Therefore, the backlight device of the present invention has an effect of reducing the cost by making the size of the second light emitting diode smaller than the size of the first light emitting diode.

The backlight device of the present invention further includes
The number of the second light emitting diodes provided in the backlight device for each type is smaller than the number of the first light emitting diodes.

  As described above, the second light emitting diode is provided in the backlight device in order to adjust the luminance and color temperature of the white light generated by the backlight device. Therefore, compared to the first light-emitting diode that emits the light that is the basis of white light, the luminance of the light emitted from the second light-emitting diode for each type is sufficient. Therefore, the number of second light emitting diodes included in the backlight device can be smaller than the number of first light emitting diodes.

  Therefore, the backlight device of the present invention has an effect of reducing cost by making the number of the second light emitting diodes for each type smaller than the number of the first light emitting diodes.

The backlight device of the present invention further includes
The first light emitting diode is sealed with a sealing resin containing the phosphor.

  With the above configuration, the phosphor has an effect of efficiently absorbing the light emitted from the first light emitting diode. Further, the distance between the first light emitting diode and the phosphor is reduced, and the effect of improving the color mixture of the light emitted from the first light emitting diode and the light emitted from the phosphor. Play.

The backlight device of the present invention further includes
The second light emitting diode is provided inside a sealing resin in which the first light emitting diode is sealed.

  With the above configuration, the distance between the second light emitting diode and the first light emitting diode is shortened. Thereby, there is an effect that the color mixture between the light emitted from the second light emitting diode and the light emitted from the first light emitting diode is improved.

The backlight device of the present invention further includes
The second light emitting diode is sealed with a transparent resin not containing the phosphor.

  With the above structure, the second light emitting diode is sealed with a transparent resin separately from the first light emitting diode.

  In general, a light emitting diode has a wavelength shift characteristic in which the wavelength of emitted light changes depending on the heat generated by itself or a change in ambient temperature. Accordingly, in the backlight device of the present invention, the second light emitting diode is sealed with the transparent resin separately from the first light emitting diode, so that the heat from the second light emitting diode, This prevents the heat from the light emitting diodes from affecting each other. As a result, the backlight device has an effect of reducing the wavelength shift due to the temperature change of the light emitting diode as much as possible.

The backlight device of the present invention further includes
The second light emitting diode includes a second light emitting diode having a relatively small wavelength shift due to temperature and a second light emitting diode having a relatively large wavelength shift, and the second light emitting diode having the smaller wavelength shift. The light emitting diode is provided inside the sealing resin in which the first light emitting diode is sealed, while the second light emitting diode having the larger wavelength shift is sealed with the transparent resin not including the phosphor. It is characterized by being.

  First, the degree of influence on the wavelength shift varies depending on the type of the light emitting diode. That is, there are a light emitting diode that has a large influence on the wavelength shift and a light emitting diode that has a small influence on the wavelength shift due to its own heat generation and changes in ambient temperature.

  Therefore, in the backlight device of the present invention, the second light emitting diode having a relatively small wavelength shift is sealed with the sealing resin together with the first light emitting diode. It is possible to improve the color mixture of light emitted by the light emitting diodes.

  Furthermore, it is possible to reduce the wavelength shift by individually sealing the second light emitting diodes having a relatively large wavelength shift with a transparent resin one by one.

  As described above, in the backlight device of the present invention, the first light-emitting diode and the second light-emitting diode are sealed with the sealing resin or the transparent resin according to the characteristics of the wavelength shift that is different for each type of light-emitting diode. be able to. Therefore, the backlight device has an effect of improving the color mixture of the light of the first light emitting diode and the second light emitting diode and reducing the wavelength shift of the first light emitting diode and the second light emitting diode.

The backlight device of the present invention further includes
The phosphor is a phosphor that emits light of at least one of the three primary colors of light.

  The phosphor contained in the sealing resin emits light of at least one of the three primary colors of light, so that the white light generated by the backlight device includes the wavelength component of the primary color light. Become. Therefore, the color rendering property of white light generated by the backlight device is improved.

  The color rendering properties indicate the luminance balance of the wavelength components of the light that constitutes white light.

The backlight device of the present invention further includes
The phosphor is a combination of a phosphor that emits light of at least one of the three primary colors of light and a phosphor that emits light of a complementary color different from the three primary colors of light. Yes.

  With the above configuration, the white light generated by the backlight device includes the wavelength component of the primary color light and the wavelength component of the complementary color light. Therefore, there is an effect that the color rendering of white light generated by the backlight device is further improved.

The backlight device of the present invention is
A plurality of third light emitting diodes that emit light of a plurality of wavelengths, and at least one phosphor that absorbs light from the third light emitting diodes and emits light of the same wavelength as the absorbed light It is characterized by having.

  First, the third light emitting diode causes a wavelength shift of emitted light due to its own temperature change and ambient temperature change. Here, when the white light generated in the backlight device is generated using only the third light emitting diode, the luminance and color temperature of the white light from the backlight device are changed by the wavelength shift of the third light emitting diode. There is a problem of changing.

  In Patent Document 2, a temperature compensation circuit for correcting a wavelength shift due to a temperature change of the light emitting diode is provided, and a wavelength shift due to a temperature change of the light emitting diode is taken by adjusting a current supplied to the light emitting diode. . However, in the configuration of Patent Document 2, since the temperature compensation circuit is provided, the design of the backlight device becomes complicated, and further, an IC that constitutes the temperature compensation circuit is separately required, leading to a problem that the cost is increased. .

  Here, the backlight device of the present invention includes a phosphor that absorbs light from the third light emitting diode and emits light having the same wavelength as the absorbed light. Further, unlike a light emitting diode, a phosphor does not cause a wavelength shift due to a change in ambient temperature.

  Therefore, in the backlight device of the present invention, even if a wavelength shift occurs in the third light emitting diode, the phosphor emits light having the same wavelength as that of the third light emitting diode before the wavelength shift. There is an effect that changes in luminance and color temperature of white light due to the shift can be reduced.

The color temperature adjustment method of the present invention includes:
A backlight device comprising: a first light emitting diode; and a phosphor that absorbs light emitted from the first light emitting diode and emits light having a wavelength different from the absorbed light. A color temperature adjustment method for adjusting a color temperature of white light generated by a light emitting diode and the phosphor, wherein the backlight device further includes light having a wavelength different from that of the light of the first light emitting diode. And a first step of adjusting the color temperature of the white light by adjusting the luminance of the light emitted from the second light emitting diode. It is a feature.

  First, the color temperature of white light is determined by the ratio of the luminance of each light constituting the white light.

  At this time, the luminance of the light emitted from the phosphor is determined by the luminance of the light from the first light emitting diode. For this reason, the brightness | luminance of the light from a 1st light emitting diode and the brightness | luminance of the light from fluorescent substance cannot be adjusted separately. Therefore, since the ratio of the luminance between the light from the first light emitting diode and the light from the phosphor is constant, the color temperature is adjusted in the white light generated by the first light emitting diode and the phosphor. There is a problem that can not be.

  Here, the color temperature adjusting method of the present invention can adjust the color temperature of white light by adjusting the luminance of light from the second light emitting diode provided in the backlight device.

  Specifically, the brightness of the light from the second light emitting diode is adjusted separately from the light from the first light emitting diode by adjusting the current value of the current flowing through the second light emitting diode. Further, the second light emitting diode emits light having a wavelength different from that of the light from the first light emitting diode. Therefore, the color temperature adjustment method of the present invention can adjust the luminance ratio of each light constituting the white light by adjusting the luminance of the light from the second light emitting diode. As a result, the color temperature adjusting method of the present invention has an effect that the color temperature of white light generated by the backlight device can be adjusted.

The color temperature adjustment method of the present invention further includes:
The ratio of the luminance of light from the first light emitting diode and the luminance of light from the second light emitting diode is made constant, and light is emitted from the first light emitting diode and the second light emitting diode. It is characterized by comprising a second step of adjusting the luminance of the light and adjusting the luminance of the white light whose color temperature has been adjusted in the first step.

  With the above feature, the color temperature adjusting method of the present invention can adjust the brightness of white light without changing the color temperature of the white light adjusted in the first step.

  Specifically, in the second step, when adjusting the brightness of white light, the ratio between the brightness of light emitted from the first light emitting diode and the brightness of light emitted from the second light emitting diode is set. It is constant. The color temperature of white light is determined by the ratio of the luminance of each light constituting the white light. Therefore, the color temperature of the white light adjusted in the first step is made constant by keeping the ratio between the luminance of the light emitted from the first light emitting diode and the luminance of the light emitted from the second light emitting diode constant. Will be prevented from shifting.

  Therefore, the ratio between the luminance of light emitted from the first light emitting diode and the luminance of light emitted from the second light emitting diode is made constant, and light is emitted from the first light emitting diode and the second light emitting diode. By adjusting the brightness of the emitted light and adjusting the brightness of the white light, the brightness of the white light can be adjusted without changing the color temperature of the white light adjusted in the first step. The effect which becomes.

  As described above, the backlight device of the present invention adjusts the luminance and color temperature of white light generated from the light from the first light emitting diode and the phosphor, and at least one second light emitting diode. The second light emitting diode emits light having a wavelength different from that of the light from the first light emitting diode.

  Furthermore, the luminance and color temperature adjusting method of the present invention includes the first step of adjusting the color temperature of white light by adjusting the luminance of light emitted from the second light emitting diode as described above. ing.

  Therefore, the backlight device and the color temperature adjusting method of the present invention can adjust the color temperature of white light generated by the light emitting diode and the phosphor.

Embodiment 1
A first embodiment of the present invention will be described below with reference to FIGS.

(Configuration of backlight device)
First, the configuration of the backlight device according to the present embodiment will be described below with reference to FIGS. 1 (a) and 1 (b).
Fig.1 (a) is a schematic diagram which shows the structure of the backlight apparatus 1 which concerns on this embodiment.

  As shown in FIG. 2A, the backlight device 1 includes a wiring board 10 and LED modules 20 regularly arranged on the wiring board 10, and the wiring board 10 and each LED module 20 are Are electrically connected.

  Here, the backlight device 1 supplies current from a power supply circuit (not shown) to the LED module 20. Furthermore, the LED module 20 supplies the supplied current to the mounted LED, thereby causing the mounted LED to emit light and generating white light. The white light generated from the LED module 20 is diffused by the diffusion sheet 103 and the diffusion plate 104, passes through the prism sheet 102, and is irradiated onto the liquid crystal panel 101 (see FIG. 10).

(Configuration of LED module 20)
Below, with reference to FIG.1 (b), the structure of the LED module 20 is demonstrated.
FIG. 1B is a schematic diagram showing a configuration of the LED module 20 disposed on the wiring board 10 of the backlight device 1.

  As shown in FIG. 4B, the LED module 20 includes a blue LED 21 that emits blue light (corresponding to the first light-emitting diode described in the claims), and a wavelength different from that of the light from the blue LED 21. The green LED 22 that emits green light (corresponding to the second light emitting diode described in the claims) and the red light that emits red light having a wavelength different from that of the light from the blue LED 21. It is comprised by LED23 (equivalent to the 2nd light emitting diode as described in the claim), LED frame 25 which is a board | substrate for modules, and sealing resin 24 containing fluorescent substance.

  Here, in the present embodiment, the blue LED 21, the green LED 22, and the red LED 23 are chip-shaped LEDs. The green LED 22 and the red LED 23 have a chip size called a small size of about 400 μm, and the blue LED 21 has a chip size of a large size of about 1000 μm.

  Further, the sealing resin 24 includes two types of phosphors. Specifically, the sealing resin 24 absorbs blue light emitted from the blue LED 21 and emits green light having a wavelength different from the absorbed light, and blue light emitted from the blue LED 21. And a red phosphor that emits red light having a wavelength different from that of the absorbed light.

  Further, the blue LED 21, the green LED 22, and the red LED 23 are mounted on the LED frame 25 and are electrically connected to the LED frame 25. The LED frame 25 has a connection terminal that is electrically connected to the wiring board 10 (see FIG. 2A). The wiring board 10 is electrically connected to the blue LED 21, the green LED 22, and the red LED 23. Have a role to connect. Further, the blue LED 21, the green LED 22, and the red LED 23 are sealed in the LED frame 25 by a sealing resin 24 including a green phosphor and a red phosphor.

(Generation of white light)
Next, generation of white light irradiated on the liquid crystal panel in the backlight device 1 according to the present embodiment will be described.

  First, the backlight device 1 supplies current to the blue LED 21 via the wiring substrate 10 and the LED frame 25 to cause the blue LED 21 to emit light. When the blue LED 21 emits light, the green phosphor and the red phosphor included in the sealing resin 24 absorb blue light from the blue LED 21 and emit green light and red light. At this time, the LED module 20 emits white light by the blue light from the blue LED 21 that has passed through the sealing resin 24 and the green light and red light from the green phosphor and the red phosphor.

Here, FIG. 2 shows a spectral distribution of white light emitted from the LED module 20 when only the blue LED 21 emits light.
FIG. 2 is an explanatory diagram illustrating an example of a spectral distribution of white light emitted from the LED module 20 when only the blue LED 21 emits light.

  As shown in the figure, when only the blue LED 21 emits light, the spectral distribution of white light emitted from the LED module 20 has the highest luminance in the vicinity of a wavelength of 450 nm indicating blue light. Furthermore, the luminance near the wavelength of 520 nm indicating green light and the luminance near the wavelength of 640 nm indicating red light are smaller than the luminance of blue light. Thus, if the brightness | luminance of green light and red light is small compared with the intensity | strength of blue light, it will show that the balance of the brightness | luminance and color temperature of the white light emitted from LED module 20 is bad.

  Here, the backlight device 1 supplies current to the green LED 22 and the red LED 23 in order to adjust the luminance and color temperature of the white light from the LED module 20 when only the blue LED 21 emits light. The red LED 23 is caused to emit light. The backlight device 1 adjusts the brightness and color temperature of white light emitted from the LED module 20 by adjusting the current values supplied to the green LED 22 and the red LED 23.

Here, the spectral distribution of the green light and the red light emitted from the green LED 22 and the red LED 23 will be described with reference to FIG.
FIG. 3 is an explanatory diagram showing spectral distributions of green light and red light emitted from the green LED 22 and the red LED 23.

  As shown in the figure, the green LED 22 and the red LED 23 have lower luminance than the luminance of the blue light emitted from the blue LED 21 shown in FIG. This is because the green LED 22 and the red LED 23 use small-sized LED chips that are smaller than the blue LED 21.

  In this embodiment, the brightness and color temperature of white light when only the blue LED 21 shown in FIG. 2 is caused to emit light are adjusted by the green light and red light emitted from the green LED 22 and the red LED 23 shown in FIG. is doing.

Next, with reference to FIG. 4, the spectral distribution of white light whose luminance and color temperature are adjusted by the green LED 22 and the red LED 23 will be described.
FIG. 4 is an explanatory diagram showing the spectral distribution of white light whose luminance and color temperature are adjusted by the green LED 22 and the red LED 23.

  As shown in the figure, the white light whose luminance and color temperature are adjusted by the green LED 22 and the red LED 23 is near 520 nm indicating green light compared to the white light when only the blue LED 21 shown in FIG. 1 is emitted. The intensity and the luminance around 640 nm showing red light are high. Thereby, the brightness | luminance of green light and red light approaches the brightness | luminance of 450 nm which shows blue light, and the balance of the color temperature of the white light produced | generated with the backlight apparatus is improving.

  As described above, the green LED 22 and the red LED 23 can adjust the brightness and color temperature of white light generated in the backlight device.

  Furthermore, the green LED 22 and the red LED 23 use small-sized LEDs that are smaller than the blue LED 21. Generally, the price of an LED becomes lower as the size becomes smaller.

  When white light having a good color temperature balance as shown in FIG. 4 is generated by only the three primary color LEDs, the LED emitting green light and the LED emitting red light have the same size as the blue LED 21. And an equivalent number is required.

  Here, in the present embodiment, as shown in FIG. 3, the green light and the red light emitted from the green LED 22 and the red LED 23 are sufficient to have a lower luminance than the blue light emitted from the blue LED 21. . Therefore, since the green LED 22 and the red LED 23 can be made into small-sized LEDs that are smaller and less expensive than the blue LEDs 21, the backlight device can be manufactured at a lower price than when white light is generated only by the LEDs. It becomes possible to do.

(Brightness and color temperature adjustment method)
Next, a method for adjusting the brightness and color temperature of white light will be described with reference to FIG.
FIG. 5 is a flowchart showing a method of adjusting the luminance and color temperature of white light emitted from the backlight device.

  First, as shown in Step 1 of the figure, the backlight device 1 supplies a current only to the blue LED 21 that excites the phosphor. The blue LED 21 supplied with the current emits blue light. Further, the green phosphor and the red phosphor contained in the sealing resin 24 absorb blue light from the blue LED 21 and emit green light and red light.

  Next, in step 2, the backlight device 1 measures the luminance of white light composed of blue light, green light, and red light from the blue LED 21, the green phosphor, and the red phosphor. Regarding the measurement of the brightness, the backlight device 1 determines the brightness of the light emitted by each LED from the information on the ambient temperature of the LED and the current flowing through the LED by arranging a temperature sensor near each LED. calculate.

  Regarding the calculation of the brightness of the light emitted by each LED, the correlation between the brightness of the light emitted by each LED, the ambient temperature of each LED, and the current flowing through each LED is measured in advance. Using the measured data, the backlight device 1 calculates the luminance of the light emitted from each LED. The calculation of the luminance of the light emitted from each LED using the correlation data measured in advance is the same in other embodiments.

  Next, the backlight device 1 obtains the brightness of the white light from the calculated information on the brightness of the light from each LED. Moreover, you may provide a color sensor in the backlight apparatus 1 instead of the said temperature sensor. In this case, the color sensor measures the luminance of white light and outputs the measured information to the backlight device 1, so that the backlight device 1 can obtain information on the luminance of white light.

  Furthermore, the backlight device 1 adjusts the current flowing through the blue LED 21 based on the value of the brightness of the white light measured in step 2, and brings the brightness of the white light closer to the target value (step 3).

  Next, the backlight device 1 measures the color temperature of white light after adjusting the luminance in step 3 (step 4). In this case as well, similarly to step 2, the brightness of the light emitted from each LED is determined from the information from the temperature sensor or color sensor arranged near each LED and the current value flowing through the LED. Is calculating. Further, the backlight device 1 obtains the color temperature of white light from the ratio of the luminance of the light emitted by each LED.

  Next, the backlight device 1 individually adjusts the currents flowing through the green LED 22 and the red LED 23, which are LEDs for adjustment, based on the value of the color temperature of the white light measured in step 4, thereby adjusting the color temperature of the white light. The target value is adjusted (step 5; corresponding to the first step described in the claims).

  Further, the backlight device 1 remeasures the luminance of the white light whose color temperature is adjusted in step 5 (step 6). The backlight device 1 determines whether the luminance of the white light remeasured in Step 6 is different from the target value (Step 7). Here, when the brightness of the white light remeasured in Step 6 is different from the target value in the determination in Step 7, the backlight device 1 emits light emitted from the blue LED 21, the green LED 22, and the red LED 22. The ratio of the luminance of light is obtained (step 8). Also in this case, as described in step 2, the backlight device 1 determines the luminance of each light emitted from the blue LED 21, the green LED 22, and the red LED 22 from the ambient temperature of the LED and the current value flowing through each LED. Find the ratio. Next, the backlight device 1 adjusts the current value of each LED while maintaining a constant ratio of the luminance of each light emitted from each LED, which is obtained in Step 8, and sets the luminance of white light to the target value. (Step 9; corresponding to the second step described in the claims).

  As described above, in step 5, after the backlight device 1 adjusts the color temperature of white light, the luminance ratio in step 9 is adjusted by keeping the ratio of the luminance of each light emitted from each LED constant. The backlight device 1 avoids the color temperature of white light from deviating.

  Moreover, in this embodiment, blue LED21, green LED22, and red LED23 are sealed with one sealing resin. This has the effect that the color mixing of the light emitted by each LED is improved as compared with the case where each LED is individually sealed.

  In this embodiment, the blue LED 21 is used as the LED that excites the phosphor contained in the sealing resin. However, the backlight device according to the present invention is not limited to this, and light other than blue light is used. It may be an LED that emits light.

  Further, in the present embodiment, each LED included in the backlight device is disposed on the wiring board 10 via the LED module, but the backlight device according to the present invention is not limited to this, It may be arranged directly on the wiring board 10.

  Furthermore, in the present embodiment, the sealing resin 24 that seals each LED includes a phosphor. However, the backlight device according to the present invention is not limited to this, and the phosphor is placed on the wiring board. You may arrange directly.

  In the following second to fourth embodiments, portions different from those of the first embodiment will be described, and descriptions of overlapping portions will be omitted.

[Embodiment 2]
Next, the configuration of the backlight device 2 according to the second embodiment of the present invention will be described below with reference to FIGS. 6 (a) and 6 (b).
Fig.6 (a) is a schematic diagram which shows the structure of the backlight apparatus 2 which concerns on this embodiment.

  As shown in FIG. 1A, the backlight device 2 includes a wiring board 10 and LED modules 30 and LED modules 40 regularly arranged on the wiring board 10, and the wiring board 10 and The LED module 30 and each LED module 40 are electrically connected.

  Here, the backlight device 2 supplies a current from a power supply circuit (not shown) to the LED module 30 and the LED module 40.

(Configuration of LED module 30 and LED module 40)
Below, with reference to FIG.6 (b), the structure of the LED module 30 and the LED module 40 is demonstrated.
FIG. 6B is a schematic diagram showing the configuration of the LED module 30 and the LED module 40 arranged on the wiring board 10 of the backlight device 2.

  First, the configuration of the LED module 30 will be described. As shown in FIG. 2B, the LED module 30 is composed of a blue LED 21 that emits blue light, an LED frame 25, and a sealing resin 34 including a phosphor. Here, the sealing resin 34 includes a yellow phosphor that absorbs blue light emitted from the blue LED 21 and emits yellow light having a wavelength different from the absorbed light.

  The blue LED 21 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the blue LED 21 is sealed with a sealing resin 34.

  Next, the configuration of the LED module 40 will be described. As shown in FIG. 4B, the LED module 40 includes a green LED 42 that emits green light, an LED frame 25, and a transparent sealing resin 44 that does not include a phosphor (transparent as described in the claims). (Corresponding to resin).

  The green LED 42 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the green LED 42 is sealed with a sealing resin 44.

  The size of the blue LED 21 is called a large size of about 1000 μm, and the size of the green LED 42 is also called a large size of about 1000 μm, similar to the size of the blue LED 42.

(Generation of white light)
Next, generation of white light in the backlight device 2 according to the present embodiment will be described.

  First, the backlight device 2 supplies current to the blue LED 21 via the LED frame 25 to cause the blue LED 21 to emit light. The blue phosphor emitted by the blue LED 21 is absorbed by the yellow phosphor contained in the sealing resin 34 and emits yellow light. White light of the backlight device 2 is generated from the blue light and the yellow light emitted by the blue LED 21 and the yellow phosphor.

  However, white light generated when current is supplied only to the blue LED 21 lacks color rendering. Here, as illustrated in FIG. 6A, the backlight device 2 includes an LED module 40. The backlight device 2 supplies a current to the LED module 40 and causes the green LED 42 to emit light, thereby generating green light. With the green light from the green LED 42, the backlight device 2 improves the color rendering of white light generated by itself. Further, the backlight device 2 adjusts the brightness and color temperature of white light by adjusting the current supplied to the green LED 42.

  Furthermore, unlike the first embodiment, the backlight device 2 individually seals green LEDs 42 that are LEDs for adjusting luminance and color temperature with a transparent sealing resin 44.

  In general, an LED causes a wavelength shift in which the wavelength of emitted light changes due to its own heat generation or change in ambient temperature. Therefore, like the backlight device 2, the blue LED 21 and the green LED 42 are individually sealed, thereby preventing the heat generated by the blue LED 21 and the green LED 42 from affecting each other. As a result, the temperature change of each blue LED 21 and green LED 42 is achieved by individually sealing each blue LED 21 and green LED 42 as in this embodiment, rather than when a plurality of LEDs are sealed with one sealing resin. The wavelength shift due to can be reduced.

  Moreover, it is preferable that the LED module 40 used for adjustment of the brightness | luminance and color temperature of white light is arrange | positioned near the LED module 30. FIG. This is because by arranging the LED module 40 near the LED module 30, the color mixing of the light emitted from the LED module 40 and the LED module 30 is improved.

  The detailed method for adjusting the brightness and color temperature of white light is the same as that in the first embodiment. Specifically, the blue LED 21 in the first embodiment corresponds to the blue LED 21 in the present embodiment, and the green LED 22 and the red LED 23 in the first embodiment correspond to the green LED 42 in the present embodiment. Therefore, in this embodiment, detailed description of the method for adjusting the brightness and color temperature of white light is omitted.

[Embodiment 3]
Next, the configuration of the backlight device 3 according to the third embodiment of the present invention will be described below with reference to FIGS. 7 (a) and (b).
FIG. 7A is a schematic diagram showing a configuration of the backlight device 3 according to the present embodiment.

  As shown in FIG. 1A, the backlight device 3 includes a wiring board 10, and LED modules 50 and LED modules 60 that are regularly arranged on the wiring board 10. The wiring board 10 and each LED module 50 and LED module 60 are electrically connected.

  Here, the backlight device 3 supplies a current from a power supply circuit (not shown) to the LED module 50 and the LED module 60.

(Configuration of LED module 50 and LED module 60)
Below, with reference to FIG.7 (b), the structure of the LED module 50 and the LED module 60 is demonstrated.
FIG. 7B is a schematic diagram showing the configuration of the LED module 50 and the LED module 60 arranged on the wiring board 10 of the backlight device 3.

  First, the configuration of the LED module 50 will be described. As shown in FIG. 2B, the LED module 50 is composed of a blue LED 21 that emits blue light, an LED frame 25, and a sealing resin 54 including a phosphor. Here, the sealing resin 54 includes a yellow phosphor and a red phosphor that absorb blue light emitted from the blue LED 21 and emit yellow light and red light.

  The blue LED 21 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the blue LED 21 is sealed with a sealing resin 54. The size of the blue LED 21 is called a large size of about 1000 μm.

  Next, the configuration of the LED module 60 will be described. As shown in FIG. 2B, the LED module 60 is composed of a green LED 22 that emits green light, an LED frame 25, and a transparent sealing resin 44 that does not contain a phosphor.

  The green LED 22 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the green LED 22 is sealed with a sealing resin 44. The size of the green LED 22 is called a small size of about 400 μm.

(Generation of white light)
Next, generation of white light in the backlight device 3 according to the present embodiment will be described.

  First, the backlight device 3 supplies current to the blue LED 21 via the LED frame 25 to cause the blue LED 21 to emit light. The blue light emitted from the blue LED 21 is absorbed by the yellow phosphor and the red phosphor contained in the sealing resin 54, and emits yellow light and red light. White light of the backlight device 3 is generated by the blue light, the yellow light, and the red light emitted by the blue LED 21, the yellow phosphor, and the red phosphor.

  Here, each luminance of yellow light and red light emitted by the yellow phosphor and the red phosphor is determined by the luminance of the blue light from the blue LED 21. Therefore, since the luminance ratio of blue light, yellow light, and red light cannot be changed, the color temperature of white light generated when current is supplied only to the blue LED 21 cannot be adjusted.

  Here, the backlight device 3 can adjust the luminance and color temperature of white light generated by itself by supplying current to the green LED 22 of the LED module 60 and adjusting the current.

  The detailed method for adjusting the brightness and color temperature of white light is the same as that in the first embodiment. Specifically, the blue LED 21 in the first embodiment corresponds to the blue LED 21 in the present embodiment, and the green LED 22 and the red LED 23 in the first embodiment correspond to the green LED 22 in the present embodiment. Therefore, in this embodiment, detailed description of the method for adjusting the brightness and color temperature of white light is omitted.

[Embodiment 4]
Next, the configuration of the backlight device 4 in the fourth embodiment of the present invention will be described below with reference to FIGS. 8 (a) and 8 (b).
FIG. 8A is a schematic diagram showing a configuration of the backlight device 4 according to the present embodiment.

  As shown in FIG. 2A, the backlight device 4 includes a wiring board 10 and a plurality of LED modules 70 and LED modules 80 that are regularly arranged on the wiring board 10. The wiring board 10 and each LED module 70 and each LED module 80 are electrically connected.

  Here, the backlight device 4 supplies a current from a power supply circuit (not shown) to the LED module 70 and the LED module 80.

(Configuration of LED module 70 and LED module 80)
Below, with reference to FIG.8 (b), the structure of the LED module 70 and the LED module 80 is demonstrated.
FIG. 8B is a schematic diagram showing the configuration of the LED module 70 and the LED module 80 disposed on the wiring board 10 of the backlight device 4.

  First, the configuration of the LED module 70 will be described. As shown in FIG. 2B, the LED module 70 includes a blue LED 21 that emits blue light, an LED frame 25, a green LED 22 that emits green light, and a sealing resin 34 including a phosphor. Has been. Here, the sealing resin 34 includes a green phosphor and a red phosphor that absorb blue light emitted from the blue LED 21 and emit green light and red light.

  The blue LED 21 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the blue LED 21 is sealed in the LED frame 25 by a sealing resin 34. The size of the blue LED 21 is called a large size of about 1000 μm, and the size of the green LED 22 is called a small size of about 400 μm.

  Next, the configuration of the LED module 80 will be described. As shown in FIG. 2B, the LED module 80 is composed of a red LED 23 that emits red light, an LED frame 25, and a transparent sealing resin 44 that does not contain a phosphor.

  The red LED 23 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the red LED 23 is sealed in the LED frame 25 by a sealing resin 44. The size of the red LED 23 is called a small size of about 400 μm.

(Generation of white light)
Next, generation of white light in the backlight device 4 according to the present embodiment will be described.

  First, the backlight device 4 supplies current to the blue LED 21 via the LED frame 25 to cause the blue LED 21 to emit light. The blue light emitted from the blue LED 21 is absorbed by the green phosphor and the red phosphor contained in the sealing resin 34 and emits green light and red light. White light of the backlight device 4 is generated by the blue light, the green light, and the red light emitted by the blue LED 21, the green phosphor, and the red phosphor.

  However, the luminance of green light and red light emitted by the green phosphor and red phosphor is smaller than that of the blue light from the blue LED 21. Therefore, the color temperature of the generated white light is poor and the luminance is also weak. Therefore, the balance of the color temperature of the white light generated when only the blue LED 21 emits light is deteriorated.

  Further, the luminance of green light and red light emitted by the green phosphor and red phosphor is determined by the luminance of blue light from the blue LED 21. For this reason, the luminance ratio of blue light, green light, and red light from the blue LED 21, the green phosphor, and the red phosphor cannot be individually adjusted. Therefore, when only the blue LED 21 is caused to emit light, there arises a problem that the color temperature of white light generated from each light from the blue LED 21, the green phosphor, and the red phosphor cannot be adjusted.

  Here, the backlight device 4 supplies current to the green LED 22 in the LED module 70 and the red LED 23 in the LED module 80 to cause the green LED 22 and the red LED 23 to emit light. The backlight device 4 adjusts the luminance of the green light and the red light emitted from the green LED 22 and the red LED by adjusting the current supplied to the green LED 22 and the red LED 23, and the luminance of the white light emitted by itself and The color temperature can be adjusted.

  In the backlight device 4, the red LED 23 is mounted on a module different from the blue LED 21 and the green LED 22 and individually sealed with a sealing resin 44. In general, the red LED 22 has a problem that the wavelength shift due to the ambient temperature is larger than the blue LED 21 and the green LED 22. Therefore, the backlight device 4 uses the red LED 23 as an LED module 80 that is separate from the other LEDs, thereby suppressing the influence of heat generated from the blue LED 21 and the green LED 22 and reducing the wavelength shift due to the temperature change. .

  On the other hand, the blue LED 21 and the green LED 22 with little wavelength shift due to temperature change are mounted on one LED frame and sealed with a sealing resin 34. Thereby, the backlight device 4 can improve the color mixture of the blue light and the green light emitted from the blue LED 21 and the green LED 22.

  The detailed method for adjusting the brightness and color temperature of white light is the same as that in the first embodiment. Specifically, the blue LED 21 in the first embodiment corresponds to the blue LED 21 in the present embodiment, and the green LED 22 and the red LED 23 in the first embodiment correspond to the green LED 22 and the red LED 23 in the present embodiment. ing. Therefore, in this embodiment, detailed description of the method for adjusting the brightness and color temperature of white light is omitted.

[Embodiment 5]
Next, the configuration of the backlight device 5 according to the fifth embodiment of the present invention will be described below with reference to FIGS. 9 (a) and 9 (b).
FIG. 9A is a schematic diagram illustrating a configuration of the backlight device 5 according to the present embodiment.

  As shown in FIG. 1A, the backlight device 5 includes a wiring board 10, LED modules 90, LED modules 91, and LED modules 92 regularly arranged on the wiring board 10. . Furthermore, the wiring board 10 and the LED module 90, the LED module 91, and the LED module 92 are electrically connected.

  Here, the backlight device 5 supplies a current from a power supply circuit (not shown) to the LED module 90, the LED module 91, and the LED module 92. The LED module 90, the LED module 91, and the LED module 92 generate white light by causing each LED to be mounted to emit light by supplying the supplied current to each LED to be mounted.

(Configuration of LED module 90, LED module 91, and LED module 92)
Below, with reference to FIG.9 (b), the structure of the LED module 90, the LED module 91, and the LED module 92 is demonstrated.
FIG. 9B is a schematic diagram showing configurations of the LED module 90, the LED module 91, and the LED module 92 that are arranged on the wiring board 10 of the backlight device 5.

  First, the configuration of the LED module 90 will be described. As shown in FIG. 2B, the LED module 90 includes a blue LED 31 (corresponding to the third light emitting diode described in the claims) that emits blue light, an LED frame 25, and a phosphor. The sealing resin 93 is used. The sealing resin 93 includes a blue phosphor that absorbs blue light emitted from the blue LED 31 and emits blue light.

  The blue LED 31 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the blue LED 31 is sealed in the LED frame 25 with a sealing resin 93. The size of the blue LED 31 is called a small size of about 400 μm.

  Next, the configuration of the LED module 91 will be described. As shown in FIG. 2B, the LED module 91 includes a green LED 32 (corresponding to the third light emitting diode described in the claims) that emits green light, an LED frame 25, and a phosphor. The sealing resin 94 is used. The sealing resin 94 includes a green phosphor that absorbs green light emitted from the green LED 32 and emits green light.

  The green LED 32 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the green LED 32 is sealed in the LED frame 25 with a sealing resin 94. The size of the green LED 32 is called a small size of about 400 μm.

  Next, the configuration of the LED module 92 will be described. As shown in FIG. 2B, the LED module 92 includes a red LED 33 (corresponding to a third light emitting diode described in the claims) that emits red light, an LED frame 25, and a phosphor. And a sealing resin 95. The sealing resin 95 includes a red phosphor that absorbs red light emitted from the red LED 33 and emits red light.

  The red LED 33 is mounted on the LED frame 25 and is electrically connected to the LED frame 25. Further, the red LED 33 is sealed in the LED frame 25 with a sealing resin 95. The size of the red LED 33 is called a small size of about 400 μm.

(Generation of white light)
The backlight device 5 supplies current from a power supply circuit (not shown) to the LED module 90, the LED module 91, and the LED module 92. The LED module 90, the LED module 91, and the LED module 92 cause each LED to emit light by supplying the supplied current to the blue LED 31, the green LED 32, and the red LED 33 mounted on each LED module.

  In the LED module 90, the blue light emitted from the blue LED 31 is absorbed by the blue phosphor contained in the sealing resin 93 and emits blue light. In the LED module 91, the green phosphor emitted from the green LED 32 is absorbed by the green phosphor contained in the sealing resin 94 and emits green light. Further, in the LED module 92, the red light emitted from the red LED 33 is absorbed by the red phosphor contained in the sealing resin 95 and emits red light.

  As described above, the backlight device 5 generates white light by the blue light, the green light, and the red light emitted from the LED module 90, the LED module 91, and the LED module 92. Here, the backlight device 5 individually adjusts the currents flowing through the blue LED 31, the green LED 32, and the red LED 33 in each LED module, thereby emitting blue light, green light, and red light emitted from each LED module. The brightness of each can be changed individually. As a result, the backlight device 5 can adjust the brightness and color temperature of the white light to be generated by individually changing the brightness of the blue light, the green light, and the red light.

  However, the LED has a characteristic that a wavelength shift in which the wavelength of emitted light changes due to its own heat generation or change in ambient temperature. Therefore, even if the current flowing through each LED is adjusted to adjust the brightness and color temperature, light is emitted from each LED due to changes in the LED's own temperature and ambient temperature, such as a long light emission time. As a result, the luminance and the color temperature are shifted.

  Here, the LED module 90, the LED module 91, and the LED module 92 included in the backlight device 5 include a phosphor that emits light of the same color as the light of the internal LEDs, and the sealing resin. Generally, unlike an LED, a phosphor hardly changes the wavelength of emitted light, such as a wavelength shift due to a temperature change.

  Therefore, even if a wavelength shift occurs in the light emitted from the blue LED 31, the green LED 32, and the red LED 33, the backlight device 5 causes the wavelength shift of each LED by the phosphor contained in the sealing resin of each LED module. It becomes possible to reduce the influence of.

  In the backlight device 5 according to the present embodiment, all LED modules of the LED module 90, the LED module 91, and the LED module 92 include a phosphor that emits light of the same color as the light of the internal LED. Has stop resin. However, the backlight device according to the present invention is not limited to this, and at least one LED module has a sealing resin including a phosphor that emits light of the same color as the light of the internal LED. May be. For example, only the LED module 92 including the red LED 32 having the largest wavelength shift due to a temperature change may include a phosphor that emits red light in the sealing resin.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

In addition, you may comprise the backlight apparatus of this invention as follows.
A transmissive display device and a backlight device are provided, and the backlight device is arranged on the back surface of the display device and is composed of at least one LED (light emitting diode), and uses a short wavelength LED and a phosphor. A backlight device characterized by using a combination of LEDs (hereinafter referred to as pseudo white LEDs) and LEDs of a plurality of wavelengths (for example, R / G / B).
A transmissive display device and a backlight device are provided, and the backlight device is arranged on the back surface of the display device and is composed of at least one LED (light emitting diode), and has a plurality of wavelengths (for example, R / G / A backlight device using a combination of the LEDs of B), wherein at least one LED and the same wavelength LED are combined with a phosphor to correct luminance unevenness / color unevenness.
In the above backlight device, the backlight device is characterized in that color unevenness / luminance unevenness of an LED using a short wavelength LED and a phosphor is corrected using LEDs of a plurality of wavelengths (for example, R / G / B). .
The LED having a plurality of wavelengths may be in a form in which a plurality of (for example, three R / G / B) LED chips are mounted in one package (hereinafter referred to as a multi-chip LED).
The LEDs having a plurality of wavelengths may have a form (hereinafter referred to as a single color LED) in which a single (for example, one R / G / B) LED chip is mounted in one package.
The phosphor used in the pseudo white LED may be a complementary color phosphor.
The phosphor used in the pseudo white LED may be a primary color phosphor.
The phosphor used in the pseudo white LED may be a phosphor combining a primary color and a complementary color.
-In the said backlight apparatus, the content ratio of single color LED / multichip LED with respect to pseudo white LED is 1, It is characterized by the above-mentioned.
The content ratio of the single color LED / multi-chip LED to the pseudo white LED in the backlight device is greater than 1 or less than 1.

Further, the luminance and color temperature adjusting method of the present invention may be configured as follows.
・ Pseudo white LED is turned on under the conditions of adjusting the pseudo white LED to have a predetermined luminance and color temperature and the conditions adjusted in the above steps, and at the same time, the white LED is also turned on, and the R / G / B LED of the white LED is turned on. A method for adjusting the luminance and color temperature of a backlight device, comprising: a step of individually adjusting a flowing current value to adjust to a target color temperature; and a step of adjusting to a target luminance.
-The step of adjusting to the target luminance is performed by adjusting the luminance ratio of the pseudo white LED and the R / G / B LED of the white LED while keeping the luminance ratio constant before and after adjustment. Temperature adjustment method.
The method of adjusting the luminance and color temperature of the backlight device is characterized in that the step of adjusting to the target luminance adjusts the luminance ratio of the R / G / B LED of the white LED while keeping it constant.

  The present invention can provide a backlight device capable of reducing the cost and adjusting the luminance and the color temperature as compared with the case where light of three primary colors is generated by an LED, and a liquid crystal panel such as a color liquid crystal television. It can be used in a device having

(A) And (b) is a schematic diagram which shows the structure of the backlight apparatus in one Embodiment of this invention. It is explanatory drawing which shows the spectral distribution of the white light produced | generated from blue LED, green fluorescent substance, and red fluorescent substance in one Embodiment of this invention. It is explanatory drawing which shows spectrum distribution of the light which green LED and red LED light-emit in one Embodiment of this invention. It is explanatory drawing which shows spectrum distribution of the white light in which color temperature was adjusted with the backlight apparatus in one Embodiment of this invention. It is a flowchart figure which shows the adjustment method of the brightness | luminance and color temperature of white light in one Embodiment of this invention. (A) And (b) is a schematic diagram which shows the structure of the backlight apparatus which mounted each LED in the separate LED module in other embodiment of this invention. (A) And (b) is a schematic diagram which shows the structure of the backlight apparatus provided with the fluorescent substance of a complementary color and a primary color in one sealing resin in other embodiment of this invention. (A) And (b) is a schematic diagram which shows the structure of the backlight apparatus in which only red LED was separately mounted in the LED module in other embodiment of this invention. (A) And (b) is a model which shows the structure of the backlight apparatus which contains the fluorescent substance which light-emits the light of the same color as LED mounted in each LED module in further another embodiment of this invention. FIG. It is a schematic diagram which shows the structure of the color liquid crystal display device provided with the backlight apparatus in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Backlight apparatus 2 Backlight apparatus 3 Backlight apparatus 4 Backlight apparatus 5 Backlight apparatus 21 Blue LED (1st light emitting diode)
22 Green LED (second light emitting diode)
23 Red LED (second light emitting diode)
24 Sealing resin 31 Blue LED (third light emitting diode)
32 Green LED (third light emitting diode)
33 Red LED (third light emitting diode)
34 Sealing resin 42 Green LED (second light emitting diode)
44 Sealing resin (transparent resin)
54 Sealing resin 93 Sealing resin 94 Sealing resin 95 Sealing resin

Claims (12)

A first light emitting diode;
A phosphor that absorbs light emitted from the first light emitting diode and emits light having a wavelength different from that of the absorbed light.
Comprising at least one second light emitting diode that adjusts the color temperature of white light generated from light from the first light emitting diode and the phosphor;
The backlight device, wherein the second light emitting diode emits light having a wavelength different from that of the light from the first light emitting diode.   The backlight device according to claim 1, wherein the second light emitting diode is smaller in size than the first light emitting diode.   3. The backlight device according to claim 1, wherein the number of the second light emitting diodes included in the backlight device is smaller than the number of the first light emitting diodes. 4.   4. The backlight device according to claim 1, wherein the first light emitting diode is sealed with a sealing resin containing the phosphor. 5.   The backlight device according to claim 4, wherein the second light emitting diode is provided inside a sealing resin in which the first light emitting diode is sealed.   5. The backlight device according to claim 1, wherein the second light emitting diode is sealed with a transparent resin that does not contain the phosphor. 6. The second light emitting diode includes a second light emitting diode having a relatively small wavelength shift due to temperature, and a second light emitting diode having a relatively large wavelength shift.
The second light emitting diode having the smaller wavelength shift is provided inside the sealing resin sealing the first light emitting diode,
5. The backlight device according to claim 4, wherein the second light emitting diode having the larger wavelength shift is sealed with a transparent resin not containing the phosphor.   The backlight device according to claim 1, wherein the phosphor is a phosphor that emits light of at least one of the three primary colors of light.   The phosphor is a combination of a phosphor that emits light of at least one of the three primary colors of light and a phosphor that emits light of a complementary color different from the three primary colors of light. The backlight device according to any one of claims 1 to 8. A plurality of third light emitting diodes that emit light of a plurality of wavelengths;
A backlight device comprising: at least one type of phosphor that absorbs light from the third light emitting diode and emits light having the same wavelength as the absorbed light. A first light emitting diode;
In a backlight device comprising: a phosphor that absorbs light emitted from the first light emitting diode and emits light having a wavelength different from the absorbed light; and the first light emitting diode and the phosphor. A color temperature adjustment method for adjusting a color temperature of white light generated by the method,
The backlight device further includes a second light emitting diode that emits light having a wavelength different from that of the light of the first light emitting diode.
A color temperature adjustment method comprising a first step of adjusting a color temperature of the white light by adjusting a luminance of light emitted from the second light emitting diode. The ratio of the luminance of light from the first light emitting diode to the luminance of light from the second light emitting diode is constant, and
A second step of adjusting a luminance of light emitted from the first light emitting diode and the second light emitting diode, and adjusting a luminance of white light whose color temperature is adjusted in the first step; The color temperature adjusting method according to claim 11, wherein the color temperature is adjusted.

Images