JP2008052067A - Light source device, display device and light emitting diode chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device capable of further improving the color reproducibility of a display device while suppressing the manufacturing cost. <P>SOLUTION: Wavelength selection filters 32 for respective colors are arranged respectively corresponding to LEDs 31B, 31G, 31R for the respective colors. In the wavelength selection filters 32 for the respective colors, monochromatic rays (B color ray, G color ray, R color ray) of corresponding LEDs are transmitted while narrowing their respective spectral widths. Transmission of the B color ray and the R color ray through the color filter 15G for green color resulting in their mixing with the G color ray does not take place any longer, and consequently color purity of display light emitted from an LCD panel 1 is heightened. Furthermore, the LEDs are used as light sources, thereby making its configuration low in cost. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light source device using a light emitting diode, a display device including such a light source device as a backlight light source, and a light emitting diode chip suitable for these devices.

  In recent years, liquid crystal display devices are being replaced by cathode ray tubes (CRTs), which have been the mainstream of display devices, due to low power consumption, space saving, and cost reduction.

  There are several types of liquid crystal display devices when classified by the illumination method used when displaying an image. A typical example is a transmissive liquid crystal display device that displays an image using a light source (backlight light source) disposed behind a liquid crystal panel (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-279988

  As a light source device for a backlight in such a transmissive liquid crystal display device, a cold cathode fluorescent lamp generally called a cold cathode fluorescent lamp (CCFL) is used. However, in recent years, a mercury-free light source device has been desired in consideration of the environment, and a light source device using a light emitting diode (LED) is promising as an alternative to the CCFL.

  Incidentally, display devices are required to improve color reproducibility in order to accurately represent acquired color information. In general, when an LED is used as a light source, color reproducibility is improved as compared with a case where CCFL is used.

  Here, the display on the current standard monitor is defined in the color gamut of the sRGB standard defined by the IEC (International Electro-technical Commission). However, there are many colors that exceed the color gamut of the sRGB standard in the world, and there are object colors that cannot be displayed on a standard monitor of the sRGB standard. For example, the color gamut applied to films, digital cameras, printers, etc. has already exceeded the sRGB range.

  Therefore, as a trend in the world, the emergence of a standard monitor that supports a wide color gamut exceeding the sRGB standard is desired, but in conventional transmissive liquid crystal display devices, R (red), G (green) , B (blue) due to color mixing of each color light, the color purity cannot be sufficiently increased, and it is difficult to improve the color reproducibility.

  If a laser is used in the light source device, the color reproducibility is improved because the spectrum width is extremely narrow. However, since the laser is very expensive compared to CCFL and LED, Manufacturing cost will be high.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a light source device capable of further improving the color reproducibility of the display device while suppressing the manufacturing cost, and a display device using such a light source device. The present invention also provides a light-emitting diode chip capable of configuring these devices.

  The light source device of the present invention is a light source device as a backlight light source of a display panel that displays an image in color, and is provided for a plurality of types of monochromatic light emitting diodes having different emission spectra and for each monochromatic light emitting diode. And a wavelength selection filter that transmits monochromatic light emitted from the monochromatic light emitting diode with a narrowed spectrum width.

  The display device of the present invention includes a display panel that has a plurality of types of color filters and displays an image in color, and a light source device as a backlight light source of the display panel. The light source device includes the plurality of types of color filters. A plurality of types of monochromatic light emitting diodes corresponding to the filters and having different emission spectra, and wavelength selection filters that are provided for each monochromatic light emitting diode and transmit monochromatic light emitted from the corresponding monochromatic light emitting diode with a narrowed spectral width. It is made to have.

  In the light source device and the display device of the present invention, in each wavelength selection filter, the monochromatic light emitted from the corresponding monochromatic light-emitting diode is transmitted while being narrowed in the respective spectrum widths and guided to the display panel. Therefore, the color purity of the display light emitted from the display panel is increased.

  In the light source device of the present invention, when the display panel has a color filter for displaying a color image corresponding to a plurality of types of single color light emitting diodes, the wavelength selection filter corresponds to the wavelength selective transmission characteristics of the color filter. It is preferable to have a wavelength selection characteristic. When configured in this manner, the color purity of the display light can be increased while adapting to the wavelength selective transmission characteristics of the color filter.

  The wavelength selection filter may be configured by alternately stacking high refractive index layers and low refractive index layers and having a stacked structure in which the lowermost layer and the uppermost layer are high refractive index layers. Good. Here, “high refractive index layer” means a layer having a higher refractive index than “low refractive index layer”, and conversely, “low refractive index layer” is lower than “high refractive index layer”. It means a layer having a refractive index.

  The light-emitting diode chip of the present invention includes a monochromatic light-emitting diode and a wavelength selection filter that is provided on the monochromatic light-emitting diode and transmits monochromatic light emitted from the monochromatic light-emitting diode with a narrowed spectrum width.

  In the light emitting diode chip of the present invention, the monochromatic light emitted from the monochromatic light emitting diode is transmitted through the wavelength selective filter while the spectrum width is narrowed. Therefore, the color purity of the transmitted light, that is, the light emitted from the chip is increased.

  According to the light source device or the display device of the present invention, a wavelength selection filter corresponding to each monochromatic light emitting diode is provided, and monochromatic light from the monochromatic light emitting diode corresponding to each wavelength selective filter is transmitted with a narrowed spectral width. Since it did in this way, the color purity of the display light radiate | emitted from a display panel can be improved. In addition, since a light emitting diode is used as the light source, an inexpensive configuration can be achieved. Therefore, it is possible to further improve the color reproducibility of the display device while suppressing the manufacturing cost.

  Further, according to the light emitting diode chip of the present invention, the wavelength selective filter is provided on the monochromatic light emitting diode, and the monochromatic light from the monochromatic light emitting diode is transmitted through the wavelength selective filter with a narrowed spectral width. The color purity of the light emitted from the chip can be increased. Therefore, by using a plurality of such light emitting diode chips to emit a plurality of types of monochromatic light, the light source device and the display device of the present invention can be configured.

  Hereinafter, the best mode for carrying out the present invention (hereinafter simply referred to as an embodiment) will be described in detail with reference to the drawings.

  FIG. 1 shows a block configuration of an entire liquid crystal display device including a light source device according to an embodiment of the present invention. In addition to the LCD panel 1, the optical member 2, and the light source device 3, the liquid crystal display device 100 stores an image processing unit 101 that performs various signal processing, an LCD control unit 102 that controls the LCD panel 1 and the like, and an image signal. A video memory 103, a light source lighting device 104 for controlling the lighting operation of the light source device 3, and a Y driver 105 and an X driver 106 for driving the LCD panel 1. The light-emitting diode chip according to one embodiment of the present invention is embodied by the light source device and the liquid crystal display device according to the present embodiment, and will be described below.

  FIG. 2 shows a cross-sectional structure of a main part of the liquid crystal display device 100. This liquid crystal display device has a so-called direct-type backlight structure, and an optical member 2 is disposed directly under the LCD panel 1, and a light source device 3 including a light emitting diode (LED) 31 directly under the optical member 2. Is arranged. The light source device 3 is supported by the housing 4.

  The LCD panel 1 is configured as a transmissive liquid crystal panel, and has a configuration in which a liquid crystal layer 10 is sandwiched between a pair of glass substrates 11A and 11B. Polarizing plates 12A and 12B are arranged outside the glass substrates 11A and 11B, and a common transparent electrode (counter electrode 13B) is arranged inside the glass substrate 11B, while a plurality of pixels are arranged inside the glass substrate 11A. The electrodes 13A are arranged in a matrix. An alignment film 14B is disposed between the counter electrode 13B and the liquid crystal layer 10, and an alignment film 14A is disposed between each pixel electrode. Further, at positions corresponding to the respective pixel electrodes on the glass substrate 11B side, as shown in a plan view in FIG. 3, for example, color filters corresponding to respective colors of B (blue), G (green), and R (red) 15 (blue color filter 15B, green color filter 15G, red color filter 15R) are formed. Each of these color filters 15B, 15G, and 15R has wavelength selective transmission characteristics as shown in FIG. Details of these wavelength selective transmission characteristics will be described later.

  The optical member 2 includes a diffusion sheet 21, a prism sheet 22, and a diffusion sheet 23 in this order from the LCD panel 1 side. The diffusion sheets 21 and 23 are for diffusing the light from the light source device 3 to make the luminance distribution uniform, and the prism sheet 22 adjusts the directivity of the diffused incident light to adjust the front of the LCD panel 1. This is to increase the brightness.

  The light source device 3 includes a substrate 30, a light emitting diode (LED) 31, and a wavelength selection filter 32. The substrate 30 is disposed on the housing 4 side. On the substrate 30, for example, as shown in a plan view in FIG. 5, light in a wavelength region corresponding to each color of B, G, R (B color light, G color light). , R color light) emitting single color LEDs 31 (blue LED 31B, green LED 31G, red LED 31R) are arranged in a matrix. Each of these color LEDs 31B, 31G, and 31R has a spectral characteristic as shown in FIG. 6, for example. The wavelength selection filter 32 is directly formed on the surface of each LED corresponding to each color LED 31B, 31G, 31R, and each color wavelength selection transmission characteristic (blue wavelength selection transmission characteristic, green wavelength corresponding to each color LED). Selective transmission characteristics and red wavelength selective transmission characteristics). Details of these spectral characteristics and wavelength selective transmission characteristics will be described later.

  Here, the configuration of the wavelength selection filter 32 will be described in detail with reference to FIG. FIG. 7 shows a cross-sectional structure of the wavelength selection filter 32. The wavelength selection filter 32 is formed of an optical thin film in which high refractive index layers 32H1 to H4 and low refractive index layers 32L1 to L3 are alternately stacked on the LED 31, and the lowermost layer and the uppermost layer (in this case, the high refractive index) Layers 32H1 and 32H4) are both high refractive index layers.

The wavelength selection filter 32 can be formed by a dry process or a wet process. In the case of a dry process, it can be formed, for example, by sputtering or vapor deposition. In this case, the high refractive index layers 32H1 to H4 are made of, for example, titanium oxide such as TiO ₂ (refractive index: 2.38), niobium oxide such as Nb ₂ O ₅ (refractive index: 2.28), or Ta ₂ O ₅ (refractive index: 2.10) and other layers made of tantalum oxide are included, and the low refractive index layers 32L1 to L3 are made of, for example, silicon such as SiO ₂ (refractive index: 1.46). An oxide or a layer made of magnesium fluoride such as MgF ₂ (refractive index: 1.38) is included. On the other hand, in the case of a wet process, it can be formed by, for example, a spin coating method or a dip coating method. In this case, the high refractive index layers 32H1 to H4 and the low refractive index layers 32L1 to L3 are made of a solvent-based / solvent-free material such as a thermosetting resin or a photo-curing resin (for example, an ultraviolet curable resin). Specifically, for example, JSR Opstar (JN7102, refractive index: 1.68) is used as the high refractive index layer, and JSR Opster (JN7215, refractive index: 1.41) is used as the low refractive index layer. Can do.

  As will be described later, the wavelength selection filter 32 has wavelength selective transmission characteristics corresponding to the respective color LEDs 31B, 31G, and 31R. Therefore, the film thicknesses are different for the respective colors. Specifically, the optical film thicknesses of the high-refractive index layer and the low-refractive index layer are set to about ¼ of the center wavelength (see FIG. 9) in a desired transmission wavelength region, for example. More specifically, in the wavelength selection filter for blue, the optical film thickness of the high refractive index layer and the low refractive index layer is set to about 450 nm / 4≈110 nm, for example, and in the wavelength selection filter for green, the high refractive index is set. The optical film thickness of the layer and the low refractive index layer is set to, for example, about 520 nm / 4 = 130 nm, and in the wavelength selective filter for red, the optical film thickness of the high refractive index layer and the low refractive index layer is, for example, 640 nm / 4 = 160 nm. Try to set the degree.

  Further, the wavelength selection filter 32 is not limited to the seven-layer structure as shown in FIG. 7, and may be an odd-numbered layer structure such as a five-layer structure or a nine-layer structure, and the lowermost layer and the uppermost layer may be high refractive index layers. That's fine.

  Next, the operation of the liquid crystal display device having the above configuration will be described. First, the basic operation of this liquid crystal display device will be described.

  As shown in FIG. 1, the video signal Vsig generated by reception or reproduction is input to the video processing unit 101. The video processing unit 101 separates the video signal Vsig into a video data signal and a synchronization signal, transfers the video data signal in the X direction (horizontal scanning direction) to the video memory 103 for each scanning line, and transmits the synchronization signal to the LCD. The data is sent to the control unit 102. The LCD control unit 102 sends a control signal for controlling the Y driver 105 and the X driver 106 and sends a control signal for controlling the light source lighting device 104.

  The light source lighting device 104 controls the lighting operation of the light source device 3 based on a control signal from the LCD control unit 102. The light emitted from the light source device 3 is subjected to optical processing as will be described later by the optical member 2 and projected onto the back surface of the LCD panel 1. In the LCD panel 1, a horizontal scanning line for displaying an image is selected for each line by the Y driver 105, and the amount of transmitted light is controlled by the X driver 106 in accordance with the value stored in the image memory 133. As a result, an image corresponding to the video signal Vsig is displayed on the LCD panel 1 at a position corresponding to the synchronization signal included in the video signal Vsig.

  Here, in the light source device 3, for example, as shown in FIG. 6, the B color light emitted from the blue LED 31B, the G color light emitted from the green LED 31G, and the R color light emitted from the red LED 31R are mixed, and the blue peak PB, The light enters the optical member 2 as white light having a green peak PG and a red peak PR. While passing through the optical member 2, the white light is incident on the LCD panel 1 under the effects of uniform luminance distribution, imparting front directivity, and sp-polarized light conversion. The LCD panel 1 performs transmission luminance modulation for each pixel in accordance with a video signal input from a video processing circuit (not shown). At this time, the color filters 15B, 15G, and 15R for the colors B, G, and R of the LCD panel 1 are incident from the optical member 2 by, for example, wavelength selective transmission characteristics CFB, CFG, and CFR shown in FIG. Among the white light, the B color wavelength band, the G color wavelength band, and the R color wavelength band are selectively transmitted. As a result, color video display is performed.

  Next, with reference to FIGS. 8 to 12, each color wavelength selective transmission characteristic by the wavelength selective filter 32, which is one of the characteristic parts of the liquid crystal display device of the present invention, will be described in detail.

  First, FIG. 8 shows spectral characteristics (having a blue peak PB, a green peak PG, and a red peak PR) of each of the LEDs 31B, 31G, and 31R shown in FIG. 6, and the color filters 15B, 15G for each color shown in FIG. 15R wavelength selective transmission characteristics CFB, CFG, and CFR are superimposed. Here, originally, the blue color filter 15B selectively transmits only B color light (light in the wavelength region near the blue peak PB) from the blue LED 31B, and the green color filter 15G transmits G color light (from the green LED 31G ( Only light in the wavelength region near the green peak PG) is selectively transmitted, and the red color filter 15R selectively transmits only R color light (light in the wavelength region near the red peak PR) from the red LED 31R. Is desirable. However, as can be seen from FIG. 8, the wavelength selective transmission characteristics CFB, CFG, and CFR of the color filters 15B, 15G, and 15R for each color exhibit broad wavelength selective transmission characteristics, and the blue peak PB, the green peak PG, and the red peak PR. Has a certain peak width, for example, in the wavelength region indicated by reference numerals 51 to 53 in the figure, B-color light and R-color light are transmitted through the green color filter 31G and mixed with the G-color light. Color purity is reduced. Therefore, in this state, the color reproduction range of the liquid crystal display device becomes narrow due to a decrease in the color purity of the G color light.

  In addition to the method of the present embodiment described below, it is conceivable to narrow the transmission wavelength region of the green color filter, or to shift the blue peak PB and the red peak PR to the short wavelength side and the long wavelength side, respectively. However, since it is necessary to change the constituent material of the green color filter 15G and the green LED 31G, it is not easy and not practical.

  Therefore, in the liquid crystal display device of the present embodiment, in the light source device 3, for example, wavelength selective transmission characteristics (blue wavelength selective transmission characteristics BFB, green wavelength selective transmission characteristics as shown in FIGS. 9A to 9C, respectively). For example, as shown in FIG. 10, the width of the spectrum LB of the B color light and the spectrum LR of the R color light are narrowed by the wavelength selection filter 32 showing the BFG and the red wavelength selective transmission characteristic BFR). The light is guided to the optical member 2 and the LCD panel 1 after not overlapping with the wavelength selective transmission characteristic CFG of the green color filter 15G.

  Specifically, in the B color light wavelength selection filter 32 (arranged on the blue LED 31B) shown in FIG. 9A, the light other than the transmission wavelength region of the green color filter 15G out of the B color light from the blue LED 31B. That is, light in a shorter wavelength region than 450 to 460 nm is selectively transmitted, and light in a longer wavelength region than 450 to 460 nm indicated by an arrow in FIG. 10 is blocked (cut).

  In addition, in the R color light wavelength selection filter 32 (arranged on the red LED 31R) shown in FIG. 9C, light other than the transmission wavelength region of the green color filter 15G out of the R color light from the red LED 31R, that is, 630. The light in the wavelength region having a wavelength longer than ˜640 nm and the wavelength shorter than 660 to 670 nm is selectively transmitted, and the light in the wavelength region shorter than 630 to 640 nm shown by the arrow in FIG. Light in the long wavelength region is blocked (cut).

  On the other hand, in the G color light wavelength selection filter 32 (arranged on the green LED 31G) shown in FIG. 9B, a part of the G color light from the green LED 31G is not blocked (cut), but is transmitted as it is and is an optical member. 2 and the LCD panel 1 are guided.

  As shown in FIG. 10, the wavelength selection filter 32 blocks not only part of the G color light but also part of the B color light and the R color light. The relative visibility curve shown in FIG. As can be seen from the above, the magnitude of human visibility varies depending on the wavelength region, and is maximum at about 555 nm within the wavelength region of G color light. That is, when the part of the B color light and the part of the R color light is blocked, a reduction in the luminance of the display light emitted from the LCD panel 1 is suppressed as compared with the case where a part of the G color light is blocked, as shown in FIG. This is because if the G color light is transmitted as it is, a decrease in luminance of the display light can be avoided.

  Thus, in the liquid crystal display device of the present embodiment, for example, as shown in FIG. 12, in the wavelength selection filters for blue and red, the B-color light and R-color light emitted from the corresponding blue LEDs 31B and 31R Each spectral width is transmitted while being narrowed and guided to the LCD panel 1. Therefore, as indicated by reference numerals 54 to 56 in the figure, the spectral characteristics LB and LR of the B color light and the R color light do not overlap with the wavelength selective transmission characteristic CFG of the green color filter 15G, so that the B color light and the R color light are for green. The color filter 31G is not transmitted and mixed with the G color light, and the color purity of the G color light, and hence the color purity of the display light emitted from the LCD panel 1 is increased. Further, this does not reduce the brightness of the display light as described above.

  Next, referring to FIG. 13 and FIG. 14, Example 1 (with wavelength selection filter, light source is LED) according to the present embodiment and Comparative Example 1 (without wavelength selection filter) according to the conventional liquid crystal display device, The light source is LED) and Comparative Example 2 (no wavelength selection filter, light source is laser) will be described while comparing their characteristics. Here, FIG. 13 collectively shows the configuration, the NTSC (National Television System Committee) ratio, the Munsell color cascade content, and the manufacturing cost for each of Example 1 and Comparative Examples 1 and 2, FIG. 14 shows the color reproduction ranges of Example 1 and Comparative Example 1 on an xy chromaticity diagram. In addition, the Munsell color cascade content rate in FIG. 13 is a color reproduction range indicating how much surface colors (748 colors of the Munsell color cascade) actually exist in the world can be contained on the xy chromaticity diagram. It is one of the indicators. Reference numerals 61, 60A, 60N, and 60C shown in FIG. 14 represent Example 1, Comparative Example 1, the NTSC ratio, and the color reproduction range in the conventional CRT, respectively.

  First, since the wavelength selection filter 32 is not provided in the first comparative example unlike the first embodiment, as described above, for example, in the wavelength region indicated by reference numerals 51 to 53 in FIG. The color reproduction range of the liquid crystal display device is narrowed because the green color filter is transmitted and mixed with the G color light and the color purity of the G color light is lowered. Therefore, the NTSC ratio is as low as 105% and the Munsell color cascade content is as low as 82%.

  On the other hand, in Comparative Example 2, since a laser is used as the light source, the spectrum width of the light source becomes extremely narrow, and there is almost no possibility that B-color light or R-color light is transmitted through the green color filter and mixed with G-color light. Therefore, it can be seen that the NTSC ratio is 138%, the Munsell color cascade content is 99%, and the color reproduction range is wide. However, since the laser is very expensive compared with the LED, the manufacturing cost of the entire apparatus becomes very high.

  On the other hand, in the first embodiment, since the wavelength selection filter 32 is provided, the B color light and the R color light are not transmitted through the green color filter 31G and mixed with the G color light. The color purity of the display light is increased. Therefore, although it is inferior to the comparative example 2, the NTSC ratio is 115% and the Munsell color cascade content is 92%, both showing higher values than the comparative example 1 in which the wavelength selective filter 32 is not provided. It can be seen that the reproduction range is widened. In particular, as indicated by reference numeral 57 in FIG. 14, Example 1 contains a color from yellow to orange that could not be contained in Comparative Example 1, and the color of this region can also be expressed. I understand that In addition, since an inexpensive LED is used as the light source, the manufacturing cost of the entire apparatus can be reduced compared to Comparative Example 2 in which a laser is used as the light source.

  As described above, in the present embodiment, each color wavelength selection filter 32 corresponding to each of the color LEDs 31B, 31G, and 31R is provided, and in each of these color wavelength selection filters 32, the corresponding monochromatic light (B color light, G color light and R color light) are transmitted with the respective spectral widths narrowed, so that the color purity of the display light emitted from the LCD panel 1 can be increased. Moreover, since LED is used as a light source, it can be set as an inexpensive structure. Therefore, it is possible to further improve the color reproducibility of the liquid crystal display device while suppressing the manufacturing cost.

  Further, since each color wavelength selection filter 32 has each color wavelength selection characteristic corresponding to the wavelength selective transmission characteristic of each color filter 15, the display light is adapted to the wavelength selective transmission characteristic of each color filter 15. The color purity of can be increased.

  Further, it is only necessary to provide the wavelength selection filter 32 for each color in the light source device 3, and it is not necessary to change the configuration of the LCD panel 1 (the constituent material of the color filter 15 for each color). Can be used as is.

  In addition, since the wavelength selection filter 32 having a separate wavelength selective transmission characteristic is provided for each of the B color light, the G color light, and the R color light, for example, all the wavelength selective transmission characteristics for the B color light, the G color light, and the R color light are shared. Compared with the case where one wavelength selective transmission filter is provided, a simple wavelength selective transmission characteristic can be obtained. Therefore, compared with such a case, the wavelength selection filter 32 can be easily formed.

  Further, since the wavelength selection filter 32 blocks not only part of the G color light but also part of the B color light and the R color light, the color reproduction as described above while transmitting the G color light having high human visibility as it is. Can be improved. Therefore, it is possible to improve the color reproducibility of the display device without reducing the luminance of the display light from the LCD panel 1.

  Further, only the light in the wavelength region indicated by the reference numeral 52 in FIG. 8, that is, the wavelength region adjacent to the transmission wavelength region of the green color filter 15G, out of the R color light from the red LED 31R by the wavelength selection filter 32 for red. In addition, since light in the region on the high wavelength side (higher wavelength side than 660 to 670 nm) due to the wavelength selective transmission characteristics of the green color filter 15G is also blocked, the transmission wavelength of the green color filter 15G Compared with the case where only light in the wavelength region adjacent to the region is blocked, the color reproducibility of the display device can be further improved.

  In addition, since the wavelength selection filter 32 is formed directly on each color LED 31B, 31G, 31R, a support substrate is not required when forming the filter. In addition, since it is only necessary to alternately form the high refractive index layer and the low refractive index layer, a simple configuration can be achieved. In addition, since the liquid crystal display device has a so-called direct type configuration, it is not necessary to provide a light guide slope as in a so-called side edge type. Therefore, the wavelength selection filter 32 and the liquid crystal display device can be easily formed and manufactured.

  Further, each of the LEDs 31B, 31G, and 31R is configured as an LED chip having a wavelength selection filter 32 for each color, and each wavelength selection filter 32 has a spectrum width of monochromatic light from each of the LEDs 31B, 31G, and 31R. Since it is made narrow and permeate | transmitted, the color purity of the emitted light from an LED chip can be improved. Therefore, by using a plurality of such LED chips to emit a plurality of types of monochromatic light, the light source device and the display device of the present invention can be configured.

  Although the present invention has been described with reference to the embodiments and the like, the present invention is not limited to these embodiments and the like, and various modifications can be made.

  For example, in the above-described embodiment and the like, the case where the wavelength selection filter 32 blocks a part of the B color light and the R color light instead of a part of the G color light has been described. For example, as shown in FIG. As shown in FIG. 16, a part of the G color light may be blocked by the green wavelength selection filter having the transmission characteristic BFG1 to narrow the spectrum width. In such a configuration, the spectral characteristic LG1 of G color light does not overlap with the wavelength selective transmission characteristics CFB and CFR of the blue color filter 15B and the red color filter 15R, so that the G color light is transmitted through these color filters. Mixing with B-color light and R-color light is eliminated, and the color purity of B-color light and R-color light can be increased. Therefore, in this case as well, for example, as shown in FIG. 17A, the relationship between the cut amount of the emission spectrum of G light and the NTSC ratio, the overlap is gradually reduced as the cut amount is increased, and the color reproducibility is improved. Can be made. However, in this case, since a part of the G color light having high human visibility is blocked, for example, as shown in FIG. 17B, as the cut amount of the emission spectrum of the G color light increases, the display is performed. The radiance ratio by light is reduced (when the NTSC ratio is 115%, which is the same NTSC ratio as in Example 1, the radiance ratio is reduced to about 85% when there is no cut amount).

  In the above-described embodiment and the like, as shown in FIG. 2, the liquid crystal display device in the case where the light source device 3 is a so-called direct type has been described. However, as shown in FIG. 18, for example, the substrate 30A, the LED 31A, and the wavelength The liquid crystal display device may be configured by a so-called side edge type light source device 3A having the selection filter 32A. In this case, instead of the optical member 2, an optical member 2A further including a light guide plate 24 and a reflection sheet 25 is provided. When configured in this way, in addition to the effects of the above-described embodiment, the entire apparatus can be reduced in size, and for example, a configuration suitable for a liquid crystal display device for mobile use such as a mobile phone or a PDA (Personal Digital Assistants). It becomes possible.

  Further, in the above-described embodiment and the like, the case where the wavelength selection filter 32 is directly formed on the surface of each color LED 31B, 31G, 31R has been described, but for example, between each of the color LEDs 31B, 31G, 31R and the wavelength selection filter 32, Other layers and members may be interposed therebetween.

  Further, in the above-described embodiment, the white light is emitted from the light source device 3 by the blue LED 31B, the green LED 31G, and the red LED 31R, and the color filters 15B, 15G, 15R for each color and the colors for each color corresponding thereto. However, the types and number of colors for generating white light are not limited to the case of blue (B), green (G), and red (R). Other configurations may be used.

  In the above-described embodiments and the like, the liquid crystal display device having the LCD panel and the light source device as the backlight light source has been described. However, the present invention includes a display panel other than the LCD panel and a light source device as the backlight light source. The present invention can also be applied to other display devices.

  Furthermore, the LED chip of the present invention has a color purity of light emitted from the chip in addition to a light source device for a backlight light source of a liquid crystal display device such as a traffic light, a lighting device, an LED chip for a car headlight, etc. It can also be applied to other devices that need to be enhanced.

1 is a block diagram illustrating an overall configuration of a liquid crystal display device according to an embodiment of the present invention. It is sectional drawing showing the principal part structure of the liquid crystal display device which concerns on one embodiment of this invention. It is a top view showing the example of arrangement composition of the color filter for each color. It is a characteristic view showing the wavelength selective transmission characteristic of a color filter. It is a top view showing the example of arrangement composition of each color light emitting diode. It is a characteristic view showing the spectral characteristic of a light emitting diode. It is sectional drawing showing the detailed structure of a wavelength selection filter. It is a characteristic view for demonstrating the overlap of the wavelength range of a blue peak and a red peak, and the transmission wavelength range of the color filter for green. It is a characteristic view showing the wavelength selective transmission characteristic of a wavelength selective filter. It is a characteristic view for demonstrating the wavelength selective transmission aspect of the blue peak and red peak by the wavelength selection filter for blue and red. It is a characteristic view for demonstrating the relationship between specific luminous efficiency and a wavelength. It is a characteristic view for explaining the relationship between the spectral characteristics of the light emitting diode after transmission through the wavelength selective filter and the wavelength selective transmission characteristics of the color filter. It is a characteristic view for demonstrating the characteristic of an Example and a comparative example. It is a characteristic view showing the color reproduction range of an Example and a comparative example. It is a characteristic view showing the wavelength selection transmission characteristic of the wavelength selection filter for green concerning the modification of the present invention. It is a characteristic view for demonstrating the wavelength selective transmission aspect of the green peak by the wavelength selection filter for green shown in FIG. It is a characteristic view showing the relationship between the cut amount of the green peak by the wavelength selection filter for green shown in FIG. 15, NTSC ratio, and radiance ratio. It is sectional drawing showing the principal part structure of the liquid crystal display device which concerns on the modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display device, 101 ... Video processing part, 102 ... LCD control part, 103 ... Video memory, 104 ... Light source lighting device, 105 ... Y driver, 106 ... X driver, 1 ... LCD panel, 11A, 11B ... Glass substrate 12A, 12B ... Polarizing plate, 13A ... Pixel electrode, 13B ... Counter electrode, 14A, 14B ... Alignment film, 15 ... Color filter, 15B ... Blue color filter, 15G ... Green color filter, 15R ... Red color filter 2, 2A ... optical member, 21, 23 ... diffusion sheet, 22 ... prism sheet, 24 ... light guide plate, 25 ... reflection sheet, 3, 3A ... light source device, 30, 30A ... substrate, 31, 31A ... light emitting diode, 31B ... Blue light emitting diode, 31G ... Green light emitting diode, 31R ... Red light emitting diode, 32, 32A ... Wavelength selection wavelength 32H1-32H4 ... high refractive index layer, 32L1-32L3 ... low refractive index layer, 4,4A ... housing, CFB ... wavelength selective transmission characteristic of blue color filter, CFG ... wavelength selective transmission characteristic of green color filter , CFR: wavelength selective transmission characteristic of color filter for red, PB: blue peak, PG: green peak, PR: red peak, LB: spectral characteristic of blue light emitting diode, LG, LG1 ... spectral characteristic of green light emitting diode, LR ... Spectral characteristics of red light emitting diodes, BFB: blue wavelength selection filter, BFG, BFG1, green wavelength selection filter, BFR: red wavelength selection filter.

Claims (10)

A light source device as a backlight light source of a display panel for displaying an image in color,
Multiple types of monochromatic light emitting diodes with different emission spectra,
A light source device comprising: a wavelength selection filter that is provided for each monochromatic light emitting diode and transmits monochromatic light emitted from the corresponding monochromatic light emitting diode with a narrowed spectrum width. The display panel has a plurality of types of color filters for color image display corresponding to the plurality of types of monochromatic light emitting diodes,
The light source device according to claim 1, wherein the wavelength selective filter has a wavelength selective characteristic corresponding to a wavelength selective transmission characteristic of the color filter. The plurality of types of color filters include a blue filter, a green filter, and a red filter,
The plurality of types of single color light emitting diodes are composed of a blue light emitting diode, a green light emitting diode and a red light emitting diode,
The wavelength selective filter is:
The blue light emitting diode is provided corresponding to the blue light emitting diode, has a blue wavelength selective transmission characteristic corresponding to the wavelength selective transmission characteristic of the blue filter, and emits blue light emitted from the blue light emitting diode by the blue wavelength selective transmission characteristic. A blue wavelength selective filter that transmits light with a narrow width;
The green light emitting diode is provided corresponding to the green light emitting diode, has a green wavelength selective transmission characteristic corresponding to the wavelength selective transmission characteristic of the green filter, and emits green light emitted from the green light emitting diode by the green wavelength selective transmission characteristic. A wavelength selection filter for green that transmits light with a narrow width;
The red light emitting diode is provided corresponding to the red light emitting diode, has a red wavelength selective transmission characteristic corresponding to the wavelength selective transmission characteristic of the red filter, and red light emitted from the red light emitting diode by the red wavelength selective transmission characteristic The light source device according to claim 2, comprising a red wavelength selection filter that transmits light with a narrow width. The blue wavelength selection filter selectively transmits light outside the transmission wavelength region of the green filter among the blue light,
The light source device according to claim 3, wherein the red wavelength selection filter selectively transmits light outside the transmission wavelength region of the green filter among the red light. The blue wavelength selection filter selectively transmits light having a wavelength shorter than 450 to 460 nm among the blue light,
The light source device according to claim 4, wherein the red wavelength selection filter selectively transmits light having a wavelength longer than 630 to 640 nm among the red light. 6. The red wavelength selection filter selectively transmits light in a wavelength region having a wavelength longer than 630 to 640 nm and shorter than 660 to 670 nm among the red light. Light source device. The light source device according to claim 1, wherein at least one of the wavelength selection filters is directly formed on a surface of a corresponding monochromatic light emitting diode. Each of the wavelength selective filters has a stacked structure in which a high refractive index layer and a low refractive index layer are alternately stacked, and has a stacked structure in which a lowermost layer and an uppermost layer are high refractive index layers. Item 2. The light source device according to Item 1. A display panel having a plurality of types of color filters and displaying an image in color,
A light source device as a backlight light source of the display panel,
The light source device is
A plurality of types of monochromatic light emitting diodes corresponding to the plurality of types of color filters and having different emission spectra;
A wavelength selection filter that is provided for each single-color light emitting diode and transmits monochromatic light emitted from the corresponding single-color light-emitting diode with a narrowed spectrum width. A monochromatic light emitting diode;
A light-emitting diode chip, comprising: a wavelength selection filter provided on the monochromatic light-emitting diode and transmitting monochromatic light emitted from the monochromatic light-emitting diode with a narrowed spectrum width.

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