JP2007109616A - Light emitting device, lighting system, electrooptical device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system capable of easily adjusting white balance of white light. <P>SOLUTION: This lighting system is provided with a light emitting device having a first light emitting means, a second light emitting means and a blue light wavelength conversion means. The first light emitting means is a blue LED 24a and emits first blue light having a predetermined wavelength at a peak. The second light emitting means is a blue LED 24b and emits second blue light having a wavelength at a peak different from the predetermined wavelength. The blue light wavelength conversion means is a YAG (yttrium-aluminum-garnet)-based phosphor 23 and converts a part of the first and second blue light rays to yellow light. The lighting system is adjusted to predetermined chromaticity by adjusting both brightness values of the first and second blue light rays. Thereby, the value of the Y-axis of an xy chromaticity diagram of white light emitted by the lighting system can be changed only by using the light emitting means emitting blue light, and white light adjusted to predetermined white light chromaticity can be emitted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device used as a light source for an illumination device of an electro-optical device.

An electro-optical device typified by a liquid crystal display device has a structure in which an electro-optical material such as liquid crystal is held between two substrates. For example, in a liquid crystal display device, an illumination device is provided on the back side of the liquid crystal display panel in order to perform transmissive display. Some illuminating devices use a plurality of single-ship white LEDs (Light Emitting Diodes) as a light-emitting device as a light source. The single-chip white LED is composed of a blue LED that emits blue light having a wavelength of 430 to 480 nm and a YAG (yttrium, aluminum, garnet) phosphor. Single chip type white LED is blue light from blue LED inside.
Yellow light is generated by exciting the AG phosphor, and white light is generated by mixing blue light and yellow light. The liquid crystal display device transmits white light emitted from the illuminating device to light of each wavelength of red (R), green (G), and blue (B) laminated on the substrate of the liquid crystal display panel. Color display is realized by transmitting through the filter.

In such a single-chip type white LED, the emission chromaticity varies depending on the wavelength of the blue light emitted from the blue LED and the amount of the YAG phosphor. The following Patent Document 1 describes a method of compensating for variations in emission chromaticity by arranging a chromaticity correction LED together with the above-described white LED.

JP 2001-209049 A

However, when white light emitted from the illumination device is transmitted through a liquid crystal display panel having RGB color filters, the blue light component of white light is absorbed, so that white display is performed on the liquid crystal display panel. The chromaticity of white light at may be significantly different from the chromaticity of white light emitted from the lighting device. Recently, in addition to RGB color filters, cyan (
A liquid crystal display device having a color filter that transmits light having a wavelength of C) is also considered. However, in the liquid crystal display panel having the RGBC color filter, compared with the liquid crystal display panel having the RGB color filter, C By adding the color filter, the white point is
There is a tendency to shift to the green side.

This invention is made | formed in view of said point, and makes it a subject to provide the illuminating device which can adjust the white balance of white light easily.

One aspect of the present invention is an illumination device including a light emitting device, the light emitting device including a first light emitting unit that emits first blue light having a predetermined wavelength as a peak, and the predetermined wavelength. Second light emitting means for emitting second blue light having a peak at a different wavelength, and blue light wavelength conversion for converting a part of the first blue light and a part of the second blue light into yellow light Means, and the first blue light, the second blue light, and the white light, which is the combined light of the yellow light, have a predetermined chromaticity and the luminous intensity of the first blue light Both luminosities of the second blue light are adjusted.

For example, the illumination device functions as a backlight of a display panel, and includes a light emitting device as a light source unit. The light emitting device includes a first light emitting means, a second light emitting means,
Blue light wavelength conversion means. The first light emitting means is, for example, a blue LED, and emits first blue light having a predetermined wavelength as a peak. The second light emitting means is, for example, blue L
The ED emits second blue light having a peak at a wavelength different from the predetermined wavelength. The blue light wavelength conversion means is, for example, a YAG (yttrium, aluminum, garnet) phosphor, and converts part of the first blue light and part of the second blue light into yellow light.
By adjusting both the luminous intensity of the first blue light and the luminous intensity of the second blue light, the predetermined chromaticity is adjusted. As a result, the white light emitted from the illumination device is adjusted to the predetermined chromaticity of the white light by changing the value of the Y axis of the xy chromaticity diagram. In addition, the lighting device can emit white light adjusted to a predetermined chromaticity of white light using only light emitting means for emitting blue light.

In one aspect of the illumination device described above, the wavelength at which the first blue light peak becomes has a difference of 10 nm or more from the wavelength at which the second blue light peak is reached. At this time, the maximum width of the Y axis that can be adjusted in the xy chromaticity diagram is about 0.015, which is the minimum value of chromaticity that allows a human to visually recognize the color difference. That is, by doing so, the white balance of white light is adjusted within a chromaticity range in which a human can visually recognize the color difference.

In a preferred embodiment of the lighting device, the lighting device includes the first blue light and the second blue light.
The blue light has a peak at a wavelength in the range of 430 nm to 480 nm.

In another aspect of the present invention, an electro-optical device including the above-described illumination device and a display panel illuminated by the illumination device can be configured. The electro-optical device is, for example, a liquid crystal display device, and the display panel is, for example, a liquid crystal display panel. Here, in the display panel, when one display pixel is composed of red, green, and blue sub-pixels,
When the white light emitted from the lighting device passes through the display panel, the blue light component is absorbed,
The white balance of white light will be lost. In the illumination device described above, the luminous intensity of blue light can be adjusted, so that the blue light component of white light absorbed by the display panel can be supplemented.

In still another aspect of the invention, the electro-optical device includes a first light emitting unit that emits first blue light having a predetermined wavelength as a peak, and a second light having a peak that has a wavelength different from the predetermined wavelength. Second light emitting means for emitting blue light; and blue light wavelength converting means for converting a part of the first blue light and a part of the second blue light into yellow light, Both the luminous intensity of the first blue light and the luminous intensity of the second blue light so that the white light that is the combined light of the blue light, the second blue light, and the yellow light has a predetermined chromaticity. And a display panel including a plurality of display pixels on which light emitted from the illumination device is incident.
Each display pixel includes a plurality of sub-pixels, and the sub-pixels include a blue-based hue colored region, a red-based hue colored region, and a blue color in a visible light region whose hue changes according to a wavelength. Any one of four colored areas composed of colored areas of two hues selected from hues up to yellow is provided. Such a display panel is capable of displaying in a wide hue range, and is equipped with the above-described illumination device, thereby supplementing the blue light component of white light absorbed by the display panel and having high color reproducibility. An optical device can be provided. In this case, it is preferable that one of the colored regions of the two hues selected from the hues of blue to yellow has a hue of blue to green. Or it is preferable that the other coloring area | region of the coloring area | region of the said 2 types of hues selected in the hue from blue to yellow is a hue of green to orange. According to this, the setting of the coloring regions of the two hues is optimized, and white light with a more white balance can be obtained.

In still another aspect of the invention, the electro-optical device includes a first light emitting unit that emits first blue light having a predetermined wavelength as a peak, and a second light having a peak that has a wavelength different from the predetermined wavelength. Second light emitting means for emitting blue light; and blue light wavelength converting means for converting a part of the first blue light and a part of the second blue light into yellow light, Both the luminous intensity of the first blue light and the luminous intensity of the second blue light so that the white light that is the combined light of the blue light, the second blue light, and the yellow light has a predetermined chromaticity. And a display panel including a plurality of display pixels on which light emitted from the illumination device is incident.
One display pixel includes a plurality of sub-pixels, and the sub-pixel has a peak of the wavelength of transmitted light,
A first colored region at 415 to 500 nm, a second colored region at 600 nm or more, and 48
One of four types of colored regions including a third colored region in the range of 5 to 535 nm and a fourth colored region in the range of 500 to 590 nm is provided. Such a display panel can display in a wide hue range, but has a high color reproducibility by supplementing the blue light component of white light absorbed by the display panel by providing the above-described illumination device. An electro-optical device can be provided. In this case, it is preferable that the peak of the wavelength of the transmitted light of the third colored region is 495 to 520 nm. Alternatively, the wavelength peak of the transmitted light of the fourth colored region is 510 to 58.
It is preferably 5 nm. According to this, the setting of the said 3rd coloring area | region or the said 4th coloring area | region is optimized, and white light with more white balance can be obtained.

In still another aspect of the invention, the electro-optical device includes a first light emitting unit that emits first blue light having a predetermined wavelength as a peak, and a second light having a peak that has a wavelength different from the predetermined wavelength. A lighting device comprising: a second light emitting unit configured to emit blue light; and a blue light wavelength converting unit configured to convert a part of the first blue light and a part of the second blue light into yellow light; A display panel that includes a plurality of display pixels and on which light emitted from the illumination device is incident.
One display pixel includes a plurality of sub-pixels, and each of the sub-pixels includes any one of colored layers of red, green, blue, and cyan. One display pixel of the display panel is composed of sub-pixels each including one of colored layers of red, green, blue, and cyan. That is, in the display panel, one display pixel is composed of red, green, blue, and cyan sub-pixels. In such a display panel, the white point is shifted to the green side by adding C sub-pixels rather than a display panel in which one display pixel is composed of red, green, and blue sub-pixels. Tend.
Therefore, by using the above-described illumination device as an illumination device for a display panel in which one display pixel is composed of red, green, blue, and cyan sub-pixels, a large amount of blue light component of white light can be obtained. The white point of the white light shifted to the green side can be adjusted to the optimum white point.

In still another aspect of the invention, an electronic apparatus including the above-described electro-optical device in a display portion can be configured.

In still another aspect of the present invention, the light-emitting device includes a first light-emitting unit that emits first blue light having a predetermined wavelength as a peak, and a second blue light having a peak that has a wavelength different from the predetermined wavelength. Second light emitting means for emitting light, and blue light wavelength converting means for converting a part of the first blue light and a part of the second blue light into yellow light. Accordingly, the light emitting device can emit white light having a predetermined chromaticity using only the light emitting means that emits blue light.

In still another aspect of the present invention, a light emitting device having two light emitting means for emitting two blue lights each having a different wavelength at a peak, and a blue light wavelength converting means for converting a part of the blue light into yellow light. A manufacturing method of an electro-optical device including: a lighting device manufacturing step for manufacturing a lighting device having the light emitting device; a display panel manufacturing step for manufacturing a display panel; and a combination step of combining the lighting device and the display panel; And a luminous intensity adjusting step for adjusting the luminous intensity of both of the two blue lights. In this manner, white balance of white light can be adjusted during the manufacturing process of the electro-optical device.

In a preferred aspect of the method for manufacturing the electro-optical device, the luminous intensity adjusting step is performed in a pre-process of the combining step, and the luminous intensity of the two blue lights is based on light emitted from the illumination device. Adjust the white balance by adjusting both of the above.

In another aspect of the method for manufacturing the electro-optical device, the luminous intensity adjusting step is performed after the combining step, and the luminous intensity of the two blue lights is based on the light emitted from the display panel. Adjust the white balance by adjusting both of the above. Thereby, the white balance of the white light projected on the display screen that is actually visually recognized by the observer can be adjusted.

In a preferred aspect of the method for manufacturing the electro-optical device, the display panel includes a plurality of display pixels, and each of the display pixels has a blue color in a visible light region whose hue changes according to a wavelength. It is composed of sub-pixels of each color of a hue coloring area, a red hue coloring area, and two hue coloring areas selected from blue to yellow hues.

In another preferable aspect of the method for manufacturing the electro-optical device, the display panel includes a plurality of display pixels, and each of the display pixels has a peak of a wavelength of transmitted light in a range of 415 to 500 nm. It is composed of a colored region, a second colored region having a thickness of 600 nm or more, a third colored region having a wavelength of 485 to 535 nm, and a sub pixel of each color of a fourth colored region having a thickness of 500 to 590 nm.

In a further preferred aspect of the method for manufacturing the electro-optical device, the display panel includes a plurality of display pixels, and each of the display pixels includes red, green, blue, and cyan sub-pixels. Yes.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Configuration of liquid crystal display device]
First, the configuration and the like of the liquid crystal display device 100 according to the present embodiment will be described with reference to FIGS.

FIG. 1 is a plan view schematically showing a schematic configuration of a liquid crystal display device 100 according to the present embodiment. In FIG. 1, a color filter substrate 92 is disposed on the front side (observation side) of the paper, and an element substrate 91 is disposed on the back side of the paper. In FIG. 1, the vertical direction (column direction) on the paper surface is defined as the Y direction, and the horizontal direction (row direction) on the paper surface is defined as the X direction. In FIG. 1, each region corresponding to R (red), G (green), B (blue), and C (cyan) represents one sub-pixel SG.
The 1 × 4 subpixel SG corresponding to R, G, B, and C represents one pixel region AG.

FIG. 2 is an enlarged cross-sectional view of one pixel region AG along the cutting line AA ′ in the liquid crystal display device 100. As shown in FIG. 2, the liquid crystal display device 100 includes a liquid crystal display panel 30 and a lighting device 10. In the liquid crystal display panel 30, an element substrate 91 and a color filter substrate 92 disposed to face the element substrate 91 are bonded together via a frame-shaped sealing material 5, and liquid crystal is enclosed inside the sealing material 5. Thus, the liquid crystal layer 4 is formed. The illumination device 10 is provided on the outer surface of the element substrate 91 of the liquid crystal display panel 30.

The liquid crystal display device 100 according to the present embodiment is a liquid crystal display device for color display configured using four colors of RGBC, and an a-Si TFT (Thin Fil) as a switching element.
This is an active matrix drive type liquid crystal display device using m Transistor) elements.

A planar configuration of the element substrate 91 will be described. On the inner surface of the element substrate 91, a plurality of source lines 32, a plurality of gate lines 33, a plurality of a-Si TFT elements 37, a plurality of pixel electrodes 34, a driver IC 40, an external connection wiring 35, and an FPC ( Flexible Printed Circu
it) 41 is formed or mounted.

As shown in FIG. 1, the element substrate 91 has a protruding region 31 that protrudes outward from one side of the color filter substrate 92, and a driver IC is formed on the protruding region 31.
40 is implemented. A terminal (not shown) on the input side of the driver IC 40 is electrically connected to one end side of the plurality of external connection wirings 35, and the other end side of the plurality of external connection wirings 35 is electrically connected to the FPC 41. It is connected. Each source line 32 is formed so as to extend in the Y direction and at an appropriate interval in the X direction, and one end side of each source line 32 is connected to an output side terminal (not shown) of the driver IC 40. Electrically connected.

Each gate line 33 includes a first wiring 33a formed so as to extend in the Y direction, and a second wiring 33b formed so as to extend in the X direction from the terminal portion of the first wiring 33a. ing. The second wiring 33 b of each gate line 33 is formed to extend in the direction intersecting each source line 32, that is, in the X direction and at an appropriate interval in the Y direction. One end of one wiring 33a is electrically connected to a terminal (not shown) on the output side of the driver IC 40. TF is provided at a position corresponding to the intersection of each source line 32 and each gate line 33 between the second wirings 33b.
A T element 37 is provided, and each TFT element 37 is electrically connected to each source line 32, each gate line 33, each pixel electrode 34, and the like. Each TFT element 37 and each pixel electrode 34 are
It is provided at a position corresponding to each sub-pixel SG on the substrate 1 such as glass. Each pixel electrode 3
4 is formed of a transparent conductive material such as ITO (Indium-Tin Oxide).

A region in which a plurality of one pixel region AG is arranged in a matrix in the X direction and the Y direction is an effective display region V (a region surrounded by a two-dot chain line). In the effective display area V, images such as letters, numbers, and figures are displayed. The area outside the effective display area V is a frame area 38 that does not contribute to display. Further, each source line 32, each gate line 33, and each TFT element 37.
An alignment film (not shown) is formed on the inner surfaces of the pixel electrodes 34 and the like.

Next, the planar configuration of the color filter substrate 92 will be described. As shown in FIG. 2, the color filter substrate 92 is formed on a substrate 2 such as glass on a light shielding layer (generally called “black matrix”, hereinafter simply abbreviated as “BM”), R, G, B , C colored layer 6R
, 6G, 6B, 6C, the common electrode 8, and the like. The BM is formed at a position that partitions each subpixel SG. In the following description or drawings, when a component is shown regardless of color, it is simply written as “colored layer 6”, and when a component is shown by distinguishing colors,
For example, it is written as “colored layer 6R”. This colored layer 6 constitutes a color filter. The common electrode 8 is made of a transparent conductive material such as ITO like the pixel electrode, and is formed over substantially the entire surface of the color filter substrate 92. The common electrode 8 is a region E1 at the corner of the sealing material 5.
Are electrically connected to one end side of the wiring 36 and the other end side of the wiring 36 is
The driver IC 40 is electrically connected to an output terminal corresponding to COM.

Next, the illumination device 10 will be described. The lighting device 10 includes a light guide plate 11 and a light source unit 12. The light source unit 12 emits light L to the end surface 11 c of the light guide plate 11. The light source unit 12 includes a plurality of white LEDs 13a and 13b serving as point light sources. Here, white LEDs 13a, 1
3b is a single-chip white LED, which will be described in detail later. In FIG. 3, the top view of the illuminating device 10 which concerns on this embodiment is shown. As shown in FIG. 3, the white LEDs 13a and 13b
Are arranged in the light source unit 12 by the same number. The light L emitted from the light source unit 12 is white LE.
The combined light is a mixture of white light emitted from each of D13a and 13b.

The light L emitted from the light source unit 12 is an end surface of the light guide plate 11 (hereinafter referred to as “light incident end surface”) 11.
When entering the light guide plate 11 from c, changing the direction by repeating reflection on the light exit surface 11a and the reflection surface 11b of the light guide plate 11, and when the angle formed between the light exit surface 11a of the light guide plate 11 and the light L exceeds the critical angle,
Light exits from the light exit surface 11a of the light guide plate 11 to the liquid crystal display panel 30 as illumination light L, respectively. The liquid crystal display device 100 is illuminated by the light L passing through the liquid crystal display panel 30. Thereby, the liquid crystal display device 100 can display images, such as a character, a number, and a figure, and an observer can visually recognize an image.

In the liquid crystal display device 100, G1, G2,..., Gm−1, G are driven by the driver IC 40 based on the signal and power from the FPC 41 connected to the main board of the electronic device.
The gate lines 33 are sequentially and exclusively selected one by one in the order of m (m is a natural number), and a gate signal of a selection voltage is supplied to the selected gate line 33 while the other non-selected gates. The line 33 is supplied with a non-selection voltage gate signal. Then, the driver IC 40 applies source signals corresponding to display contents to the pixel electrodes 34 located at positions corresponding to the selected gate lines 33, respectively, corresponding S1, S2,..., Sn-1, Sn ( n is a natural number) and is supplied through the source line 32 and the TFT element 37. As a result, the alignment state of the liquid crystal layer 4 is controlled, and the display state of the liquid crystal display device 100 is switched to the non-display state or the intermediate display state.

As shown in FIG. 2, one pixel region AG in the liquid crystal display device 100 according to the present embodiment is configured by the four colored layers 6 of RGBC, but is not limited thereto.
Instead, one pixel region AG in the liquid crystal display device 100 according to the present embodiment is
It can also be constituted by three colored layers 6 of RGB, which is a general pixel region configuration.

Furthermore, each colored region provided with each colored layer 6R, 6G, 6B, 6C is connected to each subpixel S.
G corresponds to G, and one pixel area AG is composed of four (four kinds) colored areas. 4
Among the visible light regions (380 to 780 nm) in which the hue changes according to the wavelength, the color coloring region includes a blue hue coloring region, a red hue coloring region, and a hue from blue to yellow. It may be composed of colored regions of two kinds of hues selected in (1). Although it is used here as a system, for example, if it is a blue system, it is not limited to a pure blue hue, but includes a bluish purple or a bluish green. If it is a red hue, it is not limited to red but includes orange. These colored regions may be composed of a single colored layer, or may be composed of a plurality of colored layers having different hues. Also,
Although these colored regions are described in terms of hue, the hue can be set by appropriately changing the saturation and lightness.

The specific hue range of the four colored regions is, for example, that the colored region of a blue hue is blue-violet to blue-green, more preferably indigo to blue. The colored region of the red hue is orange to red. One colored region selected with a hue from blue to yellow is blue to green, more preferably blue-green to green. The other colored region selected with a hue from blue to yellow is from green to orange, more preferably from green to yellow. Or it is green to yellowish green. Here, each colored region is
The same hue is never used. For example, when a green hue is used in two colored regions selected from hues of blue to yellow, the other uses a blue or yellowish green hue for one green. Thereby, a wider range of color reproducibility than the conventional RGB colored region can be realized.

In addition, a wide range of color reproducibility has been described in terms of hue, but the hue of a colored region may be set based on the peak of the wavelength of transmitted light that has passed through the hue. For example, the blue colored region is a colored region having a wavelength peak of 415 to 500 nm, preferably a colored region of 435 to 485 nm. The red colored region is a colored region having a wavelength peak of 600 nm or more, and preferably a colored region having a wavelength peak of 605 nm or more. One colored region selected with a hue from blue to yellow is a colored region having a wavelength peak at 485-535 nm, preferably 495-52.
This is a colored region at 0 nm. The other colored region selected with a hue from blue to yellow is a colored region having a wavelength peak at 500-590 nm, preferably a colored region at 510-585 nm, or a colored region at 530-565 nm.

Moreover, you may perform the setting of the coloring area | region of 4 colors with an xy chromaticity diagram. Blue colored areas are x ≦ 0.
151, y ≦ 0.056, preferably 0.134 ≦ x ≦ 0.151, 0.034 ≦ y ≦ 0.0
56 is a colored region. The red coloring region is a coloring region satisfying 0.643 ≦ x and y ≦ 0.333, and preferably a coloring region satisfying 0.643 ≦ x ≦ 0.690 and 0.299 ≦ y ≦ 0.333. One colored region selected with a hue from blue to yellow is a colored region in which x ≦ 0.164 and 0.453 ≦ y, preferably a colored region in which 0.098 ≦ x ≦ 0.164 and 0.453 ≦ y ≦ 0.759 . The other colored region selected with a hue from blue to yellow is a colored region at 0.257 ≦ x, 0.606 ≦ y,
Preferably, it is a colored region satisfying 0.257 ≦ x ≦ 0.357 and 0.606 ≦ y ≦ 0.670.

These four colored areas can be applied within the above-described range when the sub-pixel includes a transmission area and a reflection area.

Examples of the configuration of the four colored regions include the following.
(1) Colored areas having hues of red, blue, green, and cyan (blue green).
(2) Colored areas with hues of red, blue, green, and yellow.
(3) Colored areas of red, blue, dark green, and yellow.
(4) Colored areas with hues of red, blue, emerald, and yellow.
(5) A colored region in which the hue is red, blue, dark green, or yellowish green.
(6) Colored areas with hues of red, blue-green, dark green, and yellow-green.

Moreover, although the liquid crystal display device 100 according to the present embodiment is illustrated as a completely transmissive liquid crystal display device, the present invention is not limited thereto, and a transflective liquid crystal display device may be used instead. Further, as shown in FIG. 1, the TFT element 37 is used as the switching element. However, the present invention is not limited to this, and a TFD (Thin Film Diode) element may be used instead.

[LED configuration]
FIG. 4 shows the configurations of the white LEDs 13a and 13b according to this embodiment. White LED1
Reference numerals 3a and 13b denote single-chip white LEDs. The white LED 13a is mainly composed of
The reflective frame 21 a, the blue LED 24 a, and a YAG (yttrium, aluminum, garnet) phosphor 23, and the white LED 13 b mainly includes the reflective frame 21 b, the blue LED 24 b, and the YAG phosphor 23. Is done.

As the blue LEDs 24a and 24b, those emitting blue light having a peak with a wavelength in the range of 430 nm to 480 nm are used. However, the blue LED 24b is blue LE
Blue light having a wavelength different from the wavelength of blue light emitted from D24a is emitted. The blue LEDs 24a and 24b emit blue light by flowing currents Ia and Ib, respectively. Here, if the current amounts of the currents Ia and Ib are increased, respectively, the blue LEDs 24a and 24b.
The luminous intensity of the blue light emitted from the blue LEDs 24a and 24b decreases as the current intensity of the blue light emitted from the blue LEDs 24a and 24b decreases. The current amounts of the currents Ia and Ib are independently controlled by a control device (not shown). The control device is arranged on the FPC 41 together with the LED drive circuit and the LED control circuit. In the illumination device 10 according to the present embodiment, as an example, the blue LED 24a in the white LED 13a that emits blue light having a peak at a wavelength of 450 nm is used, and the blue LED 24b in the white LED 13b has a peak at a wavelength of 460 nm. Suppose that what emits the blue light which it has is used.

The reflection frame bodies 21a and 21b are formed of a resin or the like and have a mortar-shaped recess,
A reflective film that reflects light is formed on the inner surface of the recess by plating or the like. Blue LED2
4a and 24b are respectively installed on the bottom surfaces of the recesses of the reflecting frame bodies 21a and 21b, and are sealed with transparent resins 22a and 22b mixed with the YAG phosphor 23, respectively.

The blue light emitted from the blue LEDs 24a and 24b emits yellow light (dashed arrow Ye in FIG. 4) by exciting the YAG phosphor 23, and passes through the resins 22a and 22b as they are to be emitted as blue light. And light (solid arrow B in FIG. 4). The white LEDs 13a and 13b generate white light by mixing the blue light transmitted through the resins 22a and 22b as it is and the yellow light emitted when the YAG phosphor 23 is excited.
In the white LEDs 13a and 13b, the same YAG phosphor 23 is used for both.
The amount of the system phosphor 23 is included in both the resins 22a and 22b at the same ratio. Thereby, the yellow light emitted from the white LEDs 13a and 13b both shows the same wavelength distribution and has almost the same luminous intensity.

The blue light emitted from the blue LED has a large energy. Therefore, in a single chip type white LED, by using a blue LED as a chip, light of other colors emitted when the phosphor is excited can have a high luminous intensity.

FIG. 5 shows the spectral distribution of each white light emitted from the white LEDs 13a and 13b according to this embodiment, the horizontal axis indicates the wavelength [nm] of the light, and the vertical axis indicates the luminous intensity. In FIG. 5, a graph 151 indicated by a solid line indicates the spectral distribution of light emitted from the white LED 13a, and a graph 152 indicated by a broken line indicates the spectral distribution of light emitted from the white LED 13b. The graph 151 has a sharp peak at a wavelength of 450 nm because the blue LED 24 a that emits blue light having a wavelength of 450 nm is used in the white LED 13 a. On the other hand, the graph 152 has a sharp peak at a wavelength of 460 nm because the blue LED 24 b that emits blue light having a peak at a wavelength of 460 nm is used in the white LED 13 b. Further, since the same YAG phosphor 23 is used for the white LEDs 13a and 13b, the graphs 151 and 152 each have a small mountain with a wide base that becomes the apex near the wavelength of 540 nm.

FIG. 6 shows an International Commission on Illumination (CIE) xy chromaticity diagram showing chromaticity ranges. Chromaticity range 20
Reference numeral 1 denotes a chromaticity range based on the wavelength sensitivity characteristic of the human eye, which indicates a chromaticity range that can be recognized by humans. R, G, B, and Ye in the figure indicate rough chromaticities of red, green, blue, and yellow. In FIG. 6, the chromaticity point of the blue LED 24a (wavelength 450 nm) in the white LED 13a is indicated by a point S, the chromaticity point of the blue LED 24b (wavelength 460 nm) in the white LED 13b is indicated by a point P, and the chromaticity of the YAG phosphor 23 The point is indicated by point Q. Also, straight line 21
0 is a straight line connecting point S and point Q, and straight line 211 is a straight line connecting point P and point Q. Further, in FIG. 6, a chromaticity range 202 indicated by a one-dot broken line indicates a predetermined white area.

FIG. 7 shows an enlarged view of the chromaticity range 202 of the white region. Specifically, the chromaticity range 202 is defined by four points po1, po2, po3, and po4. In the chromaticity range 202,
The range of the X value is 0.287 to 0.311, and the range of the Y value is 0.276 to 0.315.

In FIG. 7, the chromaticity range 202 is divided into four regions P1 to P4. The region P1 is defined by four points po1, po6, po9, and po5, and the value range of X is 0.291 to 0.302.
, Y ranges from 0.276 to 0.294. The region P2 has four points po6 and po2.
, Po7, and po9, the range of the X value is 0.287 to 0.298, and the range of the Y value is 0.287 to 0.304. The region P3 has four points po5, po9, po8, and po4.
The range of the value of X is 0.298 to 0.311, and the range of the value of Y is 0.282 to 0.00.
305. The region P4 is defined by four points po9, po7, po3, and po8. The value range of X is 0.296 to 0.308, and the value range of Y is 0.294 to 0.315.

Thus, when the chromaticity range 202 is divided into four regions P1 to P4, for example, the region P3,
P4 is closer to Ye in the xy chromaticity diagram of FIG. 6 than regions P1 and P2. Accordingly, white light having chromaticity points in the regions P3 and P4 becomes whiter light that is more yellowish than white light having chromaticity points in the regions P1 and P2. The region P3 is closer to R in the xy chromaticity diagram of FIG. 6 than the region P4. Therefore, the white light having a chromaticity point in the region P3 becomes whiter lighter than the white light having a chromaticity point in the region P4. On the other hand, the region P4 is closer to G in the xy chromaticity diagram of FIG. 6 than the region P3. Therefore, white light having a chromaticity point in the region P4 becomes white light that is greener than white light having a chromaticity point in the region P3.

In the illumination device 10 according to the present embodiment, the white light emitted from the light source unit 12 is a white LED.
The white light emitted from each of 13a and 13b is mixed. Therefore, white LED
The chromaticity value of the white light emitted from the light source unit 12 is adjusted by adjusting both the luminosities of the two wavelengths of blue light emitted from the blue LEDs 24a and 24b in 13a and 13b.
Can be changed between the range Y1 between the straight line 210 and the straight line 211 shown in FIG. Specifically, with respect to a certain predetermined X coordinate value, a chromaticity point where the Y coordinate value obtained from the straight line 210 and the Y coordinate value obtained from the straight line 211 fall within the chromaticity range 202 is indicated by a point T, If U, blue L
By adjusting both the luminous intensity of the blue light emitted from the ED 24a and the blue LED 24b, the value of the Y coordinate can be changed within the range of the change amount YLen with respect to the value of the predetermined X coordinate. For example, if the luminous intensity of the blue light emitted from the blue LED 24a is made larger than the luminous intensity of the blue light emitted from the blue LED 24b, the chromaticity of the white light emitted from the light source unit 12 approaches the point T. , Reddish white. On the other hand, if the luminous intensity of the blue light emitted from the blue LED 24b is larger than the luminous intensity of the blue light emitted from the blue LED 24a, the chromaticity of the white light emitted from the light source unit 12 approaches the point U. , Greenish white.

As can be seen from this, by adjusting the luminous intensity of the blue light emitted from the blue LEDs 24a and 24b, the chromaticity of the predetermined white light can be adjusted within the range Y1. That is,
It is possible to adjust the white balance of the white light emitted from the light source unit 12.

In the case of the illuminating device 10 in the present embodiment, the wavelength difference between the blue LED 24a and the blue LED 24b is 10 nm, and the amount of change YLen in the Y-axis direction of chromaticity at this time is about 0.015. In the xy chromaticity diagram, the minimum amount of change in chromaticity that allows humans to see the difference in color is also 0.
. Therefore, the wavelength difference between the blue LED 24a and the blue LED 24b is preferably 10 nm or more. This makes it possible to adjust the white balance of white light within a chromaticity range in which a human can visually recognize the color difference. Also, blue LED 24a and blue LED
The wider the difference between the wavelengths of 24b, the larger the width of the range Y1, and the larger the variation YLen. That is, it is possible to increase the width of the amount of change in chromaticity that can be adjusted in the Y-axis direction in the xy chromaticity diagram.

In order to adjust the chromaticity value of white light in the direction along the straight line 210 and the straight line 211,
It is necessary to change the intensity of white light yellow light. Therefore, in order to greatly change the X coordinate of the chromaticity value of white light, it is necessary to adjust the ratio of the YAG phosphor 23 in the resin 22 of the white LEDs 13a and 13b. In other words, the X coordinate of the chromaticity value of white light is mainly determined by the amount of the YAG phosphor 23 in the resin 22.

Some general lighting devices generate white light using LEDs of RGB colors. In such an illuminating device, the luminous intensity of each color LED also changes due to a temperature change, a change with time, and the like, and the characteristics of the change differ depending on the LED of each color. Therefore, each color L
If the amount of current flowing through the ED is kept at the amount of current set at the time of product shipment, the intensity of light emitted from each color LED will change due to temperature change or change over time. Even if the light emitted from the light is mixed, it does not become the same white light as the initially set white light. For example, when the temperature rises, the blue LED has the property of becoming brighter and the red LED
Has the property of darkening. Therefore, in a place where the temperature is high, the white color displayed on the display screen of the liquid crystal display panel becomes a bluish white color. Of the RGB LEDs, blue LEDs
Is the fastest and darkens over time, whereas the red LED has the slowest degradation. Therefore, as time passes, the white color displayed on the display screen of the liquid crystal display panel becomes reddish white.

In the illumination device 10 according to the present embodiment, only the blue LEDs are used as the chips of the white LEDs 13a and 13b. In the case of generating white light, in a general lighting device in which LEDs of each color of RGB are used, it is necessary to adjust the amount of current flowing through the LEDs of each color of RGB having three different properties. In the illumination device 10 according to the embodiment, the blue LED 2
It is only necessary to adjust the amount of current flowing through 4a and 24b. Therefore, as compared with a general lighting device in which LEDs of each color of RGB are used, the lighting device 10 according to the present embodiment can easily generate white light. Moreover, in white LED13a, 13b, one kind of blue LE
Since only D is used, the change in the luminous intensity of the white LEDs 13a and 13b due to the temperature change and the change over time changes at the same rate. Therefore, the LE of each color of RGB as described above.
Compared with the illumination device 10 that mixes D and generates white light, the illumination device 10 according to the present embodiment makes the white light white balance collapse due to temperature change or aging change more gradual. it can.

[Adjusting the white balance of white light]
As a method of adjusting the white balance of the white light emitted from the light source unit 12, a method of adjusting the white balance of the white light immediately after emitted from the illumination device 10, and the liquid crystal display panel 3
Two methods of adjusting the white balance of white light after passing through 0 can be considered.

FIG. 8 shows a flowchart of a manufacturing method of the liquid crystal display device 100 in the case of adjusting the white balance of white light immediately after the light is emitted from the illumination device 10, and FIG. 9 adjusts the white balance of white light transmitted through the liquid crystal display panel 30. The flowchart of the manufacturing method of the liquid crystal display device 100 in the case of doing is shown.

When adjusting the white balance of the white light immediately after the light is emitted from the lighting device 10, as shown in FIG. 8, first, the lighting device 10 that is the lighting device manufacturing process is manufactured (step S11).
The liquid crystal display panel 30 which is a display panel manufacturing process is manufactured (step S12). afterwards,
As the luminous intensity adjustment step, the light emitted from the blue LEDs 24a and 24b is adjusted by adjusting the currents Ia and Ib flowing through the blue LEDs 24a and 24b of the white LEDs 13a and 13b while observing the chromaticity of the white light immediately after emitted from the lighting device 10. Both the luminous intensity of the blue light to be adjusted is adjusted to adjust the white balance of the white light immediately after the light is emitted from the illumination device 10 (step S13).
After the adjustment of the white balance, the liquid crystal display device 100 is completed by combining the illumination device 10 and the liquid crystal display panel 30 as a combination process (step S14).

On the other hand, when white light is generated by adjusting the light transmitted through the liquid crystal display panel 30, FIG.
As shown in FIG. 3, the illumination device 10 that is the illumination device production process is produced (step S21), and the liquid crystal display panel 30 that is the display panel production process is produced (step S22). Thereafter, as a combination process, the lighting device 10 and the liquid crystal display panel 30 are combined (step S2).
3). After completing the device configuration of the liquid crystal display device 100 in this way, as a luminous intensity adjustment step, while observing the chromaticity of white light transmitted through the liquid crystal display panel 30 and emitting light, a white LED
By adjusting the currents Ia and Ib flowing through the blue LEDs 24a and 24b of 13a and 13b, both the intensity of the blue light emitted from the blue LEDs 24a and 24b is adjusted, and the white balance of the white light emitted from the liquid crystal display panel is adjusted. Is adjusted (step S24).

The white balance of white light can be adjusted during the manufacturing process of the liquid crystal display device 100 by the two manufacturing methods of the liquid crystal display device 100 described above.

In a liquid crystal display device having a general RGB colored layer, the light transmittance of the colored layer in the liquid crystal display panel varies depending on the thickness of the colored layer, etc., so that the light emitted from the LED passes through the colored layer. As a result, the light intensity of each color of RGB changes. Therefore, even if predetermined white light is generated on the lighting device side, the color of the white light after passing through the colored layer 6 is not always the same as the color of the predetermined white light. In other words, when white display is performed on the display screen, the white color visually recognized by the observer is not always the same as the color of the predetermined white light generated on the lighting device side. In this way, since the ratio of the light intensity of each color of RGB constituting the white light changes depending on the transmittance of the colored layer, the observer can select the white color displayed on the display screen and the predetermined light generated on the lighting device side. It looks different from the color of white light. In particular, among the light of each color of RGB, since the blue light is absorbed most by the colored layer, the blue light component in the white light is insufficient. When white display is performed on the liquid crystal display panel 30 having the RGBC colored layer 6 as in the liquid crystal display device 100 according to the present embodiment, the liquid crystal display panel having the RGB colored layer described above is used. The white point tends to shift more to the green side by adding the C colored layer 6 than when performing white display.

Thus, the chromaticity is different between the white light projected on the display screen after passing through the liquid crystal display panel 30 and the white light generated by the illumination device 10. Therefore, it is more effective to adjust the white balance of the white light displayed on the display screen that is actually visually recognized by the observer.
More appropriate display can be performed than adjusting the white balance of the white light immediately after the light is emitted.

In the illumination device 10 according to the present embodiment, the blue LEDs 24a of the white LEDs 13a and 13b,
The luminous intensity of the blue light emitted from 24b can be adjusted. In other words, when the blue light component of white light that is absorbed by the liquid crystal display panel is insufficient, the blue light component can be supplemented. Further, by using the illumination device 10 for the liquid crystal display panel 30 having the RGBC colored layer 6 as in the liquid crystal display device 100 according to the present embodiment, the blue light component of white light can be increased. The white point of white light shifted to the green side can be adjusted to the optimum white point.

[Modification]
Next, a modified example of the illumination device 10 according to the present embodiment will be described. FIG. 10 is a diagram illustrating a white LED 13 according to a modification of the illumination device 10 according to the present embodiment. In the illumination device 10 according to the present embodiment, the same number of white LEDs 13a and 13b are arranged in the light source unit 12, but the present invention is not limited to this. Instead of arranging the white LEDs 13a and 13b in the light source unit 12, the white LEDs 13 shown in FIG. 10 may be arranged. In the white LED 13, both the blue LEDs 24 a and 24 b are installed on the bottom surface of the concave portion of one reflecting frame body 21, and YA
It has a structure in which it is sealed with a transparent resin 22 mixed with a G-based phosphor 23. The blue LEDs 24a and 24b emit blue light by flowing currents Ia and Ib, respectively. The current amounts of the currents Ia and Ib are independently controlled by a control device (not shown). Blue LE
The blue light emitted from D24a and 24b is light that generates yellow light (broken arrow Ye in FIG. 10) by exciting the YAG phosphor 23, and light that passes through the resin 22 as it is and is emitted as blue light ( It is divided into a solid arrow B) in FIG. The white LED 13 generates white light by mixing blue light that has passed through the resin 22 as it is and yellow light that is emitted when the YAG phosphor 23 is excited. Also with this white LED 13, as described above, the chromaticity range in the Y-axis direction in the xy chromaticity diagram can be adjusted, and the white balance of the white light emitted from the light source unit 12 can be adjusted.

Further, the light emitting element disposed in the light source unit 12 is not limited to the white LED as described above. Instead of the white LED, an organic EL (electroluminescence) light emitting element that can emit white light by exciting phosphors having two different wavelengths may be used.
Furthermore, in the above-described embodiment, the liquid crystal display panel is used as the display panel. However, the present invention is not limited to this, and another display panel such as an electrophoretic display panel can be used instead. .

[Electronics]
Next, a specific example of an electronic apparatus to which the liquid crystal display device 100 according to this embodiment can be applied will be described with reference to FIG.

First, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 11A is a perspective view showing the configuration of this personal computer. As shown in the figure, a personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal display device 100 according to the present invention is applied.

Next, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 11B is a perspective view showing the configuration of this mobile phone. As shown in the figure, the mobile phone 720 includes a plurality of operation buttons 721, an earpiece 722, a mouthpiece 72.
3 and a display unit 724 to which the liquid crystal display device 100 according to the present invention is applied.

As an electronic apparatus to which the liquid crystal display device 100 according to the present invention can be applied, FIG.
In addition to the personal computer shown in Fig. 11 and the cellular phone shown in Fig. 11 (b), a liquid crystal television, a viewfinder type / monitor direct view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, a word processor, a work Station, video phone,
A POS terminal, a digital still camera, etc. are mentioned.

The top view of the liquid crystal display device which concerns on this embodiment. 1 is a cross-sectional view of a liquid crystal display device according to an embodiment. The top view of the illuminating device 10 which concerns on this embodiment. The schematic diagram which shows the structure of white LED which concerns on this embodiment. The spectral distribution of white light emitted from the white LED according to the present embodiment. International Commission on Illumination (CIE) xy chromaticity diagram showing chromaticity range. The enlarged view of the chromaticity range of a white area | region. The flowchart figure of the manufacturing method of a liquid crystal display device. The flowchart figure of the manufacturing method of a liquid crystal display device. The figure which shows the modification of white LED which concerns on this embodiment. FIG. 11 is a diagram showing an example of an electronic apparatus to which the liquid crystal display device of this embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Light guide plate, 12 ... Light source part as a light-emitting device, 13a, 13b ... White LED as 1st light emission means, 24a, 24b ... Blue LED as 2nd light emission means, 23 ... As blue light wavelength conversion means YAG phosphors, 10 ... illumination device, 30 ... liquid crystal display panel as display panel, 100 ... liquid crystal display device as electro-optical device.

Claims (19)

A lighting device comprising a light emitting device,
The light emitting device
First light emitting means for emitting first blue light having a peak at a predetermined wavelength;
Second light emitting means for emitting second blue light having a peak at a wavelength different from the predetermined wavelength;
Blue light wavelength conversion means for converting a part of the first blue light and a part of the second blue light into yellow light,
The intensity of the first blue light and the intensity of the second blue light are set so that the white light, which is the combined light of the first blue light, the second blue light, and the yellow light, has a predetermined chromaticity. An illumination device characterized in that both luminosities are adjusted. The wavelength that becomes the peak of the first blue light is 10 wavelengths and the wavelength that becomes the peak of the second blue light.
The illumination device according to claim 1, wherein the illumination device has a difference of nm or more. 3. The lighting device according to claim 1, wherein the first blue light and the second blue light have a peak wavelength within a wavelength range of 430 nm to 480 nm. The lighting device according to any one of claims 1 to 3,
An electro-optical device comprising: a display panel illuminated by the illumination device. First light emitting means for emitting first blue light having a peak at a predetermined wavelength;
Second light emitting means for emitting second blue light having a peak at a wavelength different from the predetermined wavelength;
Blue light wavelength conversion means for converting a part of the first blue light and a part of the second blue light into yellow light,
The intensity of the first blue light and the intensity of the second blue light are set so that the white light, which is the combined light of the first blue light, the second blue light, and the yellow light, has a predetermined chromaticity. A lighting device in which both the luminous intensity is adjusted;
A display panel including a plurality of display pixels on which light emitted from the illumination device is incident;
One display pixel of the display panel includes a plurality of sub-pixels, and the sub-pixels include a blue-based hue coloring region and a red-based hue out of a visible light region whose hue changes according to a wavelength. An electro-optical device comprising: a colored region, or any one of four colored regions composed of colored regions of two hues selected from hues from blue to yellow. 6. The electro-optical device according to claim 5, wherein one of the colored regions of the two hues selected from the hues of blue to yellow has a hue of blue to green. 6. The electro-optical device according to claim 5, wherein the other colored region of the colored regions of the two hues selected from the hues of blue to yellow is a green to orange hue. First light emitting means for emitting first blue light having a peak at a predetermined wavelength;
Second light emitting means for emitting second blue light having a peak at a wavelength different from the predetermined wavelength;
Blue light wavelength conversion means for converting a part of the first blue light and a part of the second blue light into yellow light,
The intensity of the first blue light and the intensity of the second blue light are set so that the white light, which is the combined light of the first blue light, the second blue light, and the yellow light, has a predetermined chromaticity. A lighting device in which both the luminous intensity is adjusted;
A display panel including a plurality of display pixels on which light emitted from the illumination device is incident;
One display pixel of the display panel includes a plurality of sub-pixels, and the sub-pixel includes a first colored region having a peak wavelength of transmitted light of 415 to 500 nm and a second colored region having a wavelength of 600 nm or more. And an electro-optical device comprising any one of four colored regions including a third colored region at 485 to 535 nm and a fourth colored region at 500 to 590 nm. The electro-optical device according to claim 8, wherein the wavelength peak of the transmitted light of the third colored region is in a range of 495 to 520 nm. The electro-optical device according to claim 8, wherein a peak of a wavelength of transmitted light of the fourth colored region is 510 to 585 nm. A first light emitting means for emitting a first blue light having a peak at a predetermined wavelength; a second light emitting means for emitting a second blue light having a wavelength different from the predetermined wavelength; A blue light wavelength conversion means for converting a part of the blue light of 1 and a part of the second blue light into yellow light;
A display panel that includes a plurality of display pixels and on which light emitted from the illumination device is incident;
One display pixel of the display panel includes a plurality of sub-pixels, and the sub-pixel includes any one of colored layers of red, green, blue, and cyan. An electronic apparatus comprising the electro-optical device according to claim 4 in a display unit. First light emitting means for emitting first blue light having a peak at a predetermined wavelength;
Second light emitting means for emitting second blue light having a peak at a wavelength different from the predetermined wavelength;
A light emitting device comprising: blue light wavelength conversion means for converting a part of the first blue light and a part of the second blue light into yellow light. Method for manufacturing electro-optical device including light emitting device having two light emitting means for emitting two blue lights each having a different wavelength in peak, and blue light wavelength converting means for converting a part of blue light into yellow light Because
A lighting device manufacturing step of manufacturing a lighting device having the light emitting device;
A display panel manufacturing process for manufacturing a display panel;
A combination step of combining the lighting device and the display panel;
And a luminous intensity adjusting step of independently adjusting the luminous intensity of the two blue lights. The luminous intensity adjusting step is performed before the combining step, and the white balance is adjusted by adjusting both luminous intensities of the two blue lights based on the light emitted from the lighting device. The method of manufacturing an electro-optical device according to claim 14. The luminous intensity adjusting step is performed after the combining step, and white balance is adjusted by adjusting both luminous intensity of the two blue lights based on light emitted from the display panel. The method of manufacturing an electro-optical device according to claim 14. The display panel includes a plurality of display pixels,
Each of the display pixels is selected from a blue hue coloring area, a red hue coloring area, and a hue from blue to yellow among visible light areas whose hue changes according to wavelength. 17. The method of manufacturing an electro-optical device according to claim 16, wherein the electro-optical device is composed of sub-pixels of each color in a colored region of a seed hue. The display panel includes a plurality of display pixels,
Each of the display pixels has a first colored region having a transmitted light wavelength peak of 415 to 500 nm, a second colored region of 600 nm or more, a third colored region of 485 to 535 nm, and 500 to 590 nm. 17. The method of manufacturing an electro-optical device according to claim 16, wherein each of the sub-pixels of each color of the fourth coloring region is provided. The display panel includes a plurality of display pixels,
17. The method of manufacturing an electro-optical device according to claim 16, wherein each of the display pixels includes sub-pixels of red, green, blue, and cyan colors.

Images