JP2009265135A - Display device, panel, backlight, and method of controlling display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance light use efficiency and saturation of display color of a display device as compared with the conventional pixel division drive method while suppressing a sub-frame frequency. <P>SOLUTION: The display includes a panel having a plurality of pixel formation part arranged two-dimensionally, and a first light source and a second light source having mutually different light emission spectra for irradiating the pixel formation part. The pixel formation part is composed of: a first sub-pixel formation part having a first color filter for radiating transmissive light of a first color when being irradiated with the first light source and radiating transmissive light of a second color when being irradiated with the second light source; and a second sub-pixel formation part having a second color filter for radiating transmissive light of a third color when being irradiated with the second light source. The pixel formation part is alternately radiated by the first light source and the second light source, and transmissivities of the first sub-pixel formation part and the second sub-pixel formation part are independently controlled. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device, a panel, a backlight, and a display device control method, and more particularly to a color display device.

Conventionally, a pixel division method and a field sequential method are known as color display methods for display devices (see, for example, Patent Documents 1, 2, 3, 4, 5, and 6). Different from the pixel division method, white light is dispersed by three color filters that transmit light of different colors, and color display is performed by independently controlling the intensity of light transmitted through each color filter with a liquid crystal or the like. It is. The field sequential method is a method of performing color display by independently controlling the intensity of light of three colors emitted in a time-sharing manner with a liquid crystal or the like. Patent Document 6 describes a method of performing color display by dispersing two colors of light in complementary colors with a color filter of three colors and independently controlling the intensity of light transmitted through each color filter with liquid crystal. (See, for example, FIG. 2 of Patent Document 6).
JP 2000-321551 A JP 11-119189 A JP 2003-222858 A JP 2003-114424 A JP 2005-275147 A International Publication WO2007 / 066435 Pamphlet

  However, the conventional pixel division method requires simultaneous display of at least 3 sub-pixels for 1-pixel display, and an opaque element such as a wiring or a transistor is required for each sub-pixel. Compared with the field sequential method. Light utilization efficiency is reduced. In addition, in the conventional pixel division method that separates the emitted light from the light source with three types of color filters, the intensity of the emitted light from the light source is increased to increase the brightness of the display, and the intensity of the transmitted light is increased. Therefore, the purity of the transmitted light that is the primary stimulus for the display color is lower than that of the field sequential method. On the other hand, the conventional field sequential method requires display of at least three sub-frames for one frame, and therefore requires a liquid crystal and a light source that have a quicker response than the pixel division method and a drive circuit with a high operating frequency. Become. For this reason, it is difficult for the conventional field sequential method to satisfy display performance equivalent to that of the pixel division method. In addition, the color display method described in FIG. 2 and the like of Patent Document 6 realizes color display using two light sources and three color filters having a complementary color relationship. Since opaque elements such as wirings and transistors are required for each, light use efficiency is lower than that in the field sequential method.

An object of the present invention is to provide a display device capable of suppressing the subframe frequency and improving the saturation of the display color while improving the light utilization efficiency.

  (1) A display device for achieving the above object includes a panel having a plurality of two-dimensionally arranged pixel forming units, a first light source that irradiates the pixel forming unit, and a second that irradiates the pixel forming unit. A display device comprising: a light source; and a control unit that controls the first light source, the second light source, and the panel, wherein the first light source and the second light source have different emission spectra, The pixel forming unit emits a first color transmitted light when irradiated by the first light source, and emits a second color transmitted light when irradiated by the second light source; A second subpixel forming unit that has a transmission spectrum different from that of the first subpixel forming unit and emits transmitted light of a third color when illuminated by the second light source, and the control unit includes First The light source and the second light source are alternately turned on, and the transmittance of the first sub-pixel forming part irradiated by the first light source and the first sub-pixel forming part irradiated by the second light source And the transmittance of the second sub-pixel forming portion irradiated by the second light source are controlled independently.

  According to this display device, it is possible to perform color display with higher utilization efficiency of light emitted from the light source than in the conventional pixel division method. Further, according to this display device, it is possible to display a color having higher saturation than that of the conventional pixel division method while suppressing the subframe frequency.

(2) In the display device for achieving the above object, the color of the first emitted light that is the light emitted from the first light source and the color of the second emitted light that is the light emitted from the second light source are complementary colors. It is preferable that
When the emission colors of the two light sources have a complementary color relationship, it is possible to display a highly saturated color with a good balance in the hue direction.

  (3) In the display device for achieving the above object, the first light source emits first radiated light having one or more peak bands, and the second light source has two or more peak bands. And the transmission band of the first sub-pixel forming unit includes a first peak band of the first emitted light and a first peak band of the second emitted light. Or any one of the second highest peak bands, and the transmission band of the second subpixel formation part is the transmission of the first subpixel formation part of the two peak bands of the second radiation light. It is preferable that the first peak band or the second peak band not included in the band is included.

  In this case, the use efficiency of the light emitted from the first light source and the second light source is increased, and the purity of the transmitted light that is the primary stimulus of the display color is increased, so that a color with high saturation can be displayed.

(4) The wavelength difference between the first peak band of the second emitted light and the second peak band of the second emitted light is equal to the first peak band of the first emitted light and the second peak band. It is preferable that the wavelength difference between the first peak band of the emitted light or the second peak band of the second emitted light is larger.
In this case, since the purity of transmitted light, which is the original stimulus of the display color, is higher than in the case where this is not the case, a highly saturated color can be displayed.

(5) In the display device for achieving the above object, the peak band of the first emitted light includes any one of wavelengths of R monochromatic light, G monochromatic light, and B monochromatic light, and the second The two peak bands of the second emitted light, which is the light emitted from the light source, are not included in the peak band of the first light source among the wavelengths of the R monochromatic light, the G monochromatic light, and the B monochromatic light. Preferably each includes one wavelength.
In this case, it becomes easy to perform faithful color reproduction without narrowing the color gamut compared to the case where this is not the case.

(6) In the display device for achieving the above object, the first color is preferably green.
In this case, since the intensity of the green transmitted light having the highest visibility can be controlled independently, the white balance can be controlled with higher accuracy than in other cases.

(7) In the display device for achieving the above object, it is preferable that the color of the first emitted light which is the light emitted from the first light source is green.
In this case, green light having the highest visibility can be independently emitted from the light source. It becomes easy to increase the purity of the green transmitted light having the highest visibility, and as a result, the white balance can be adjusted with high accuracy.

(8) In the display device for achieving the above object, the second sub-pixel forming unit has a transmission spectrum that transmits light of the same color as the first color when irradiated by the first light source. preferable.
Here, the same color means that two colors are expressed using the same basic color name. In this case, since the light of the same color can be transmitted to both the first sub-pixel forming part and the second sub-pixel forming part in the state where the first light source is turned on, the first light source emits light compared to the case where it is not. The use efficiency of the emitted light is increased, and the intensity of the color light obtained by being emitted from the first light source can be adjusted with high accuracy.

(9) In the display device for achieving the above object, the first light source is a cathode fluorescent tube provided with a phosphor of one wavelength as a radiation source, and the second light source emits a phosphor of two wavelengths. A cathode fluorescent tube provided as a source is preferable.
A single wavelength phosphor is a phosphor having a single peak band of emitted light. A two-wavelength phosphor is a phosphor having two peak bands of emitted light. In this case, the purity of the transmitted light that is the primary stimulus of the display color can be made higher than in the case where it is not so that a color with high saturation can be displayed.

(10) In the display device for achieving the above object, it is preferable to include a direct-type backlight having the first light source and the second light source.
In this case, the light use efficiency can be increased as compared with the case where the panel is irradiated with the edge light type backlight.

(11) In the display device for achieving the above object, the panel is applied with a data signal for controlling the transmittance of the first subpixel forming portion and the transmittance of the second subpixel forming portion. A plurality of data lines and a plurality of scanning lines that cross the data lines and to which a selection signal for controlling the change timing of the transmittance of the subpixel forming portion is applied, and the first light source and the A plurality of second light sources are provided and mixed in the arrangement direction of the scanning lines, and the control unit sequentially turns on and turns on the plurality of first light sources at the same cycle as the scanning cycle by the selection signal. It is preferable that the plurality of second light sources are sequentially turned on and off sequentially at the same cycle as the scanning cycle by the selection signal.
The mix arrangement means that the first light source and the second light source are mixed and arranged. In this case, the image can be displayed brighter than in other cases.

(12) In the display device for achieving the above object, the first light source and the second light source are preferably arranged alternately.
In this case, the display color of each pixel formation part can be made uniform compared with the case where it is not so.

(13) In the display device for achieving the above object, the first light source may include two types of LED chips having different colors, and the second light source may include one type of LED chip.
The LED chip is a unit element that emits only one color of light by a single LED or an LED and a phosphor.

(14) In the display device for achieving the above object, the first light source includes a first LED, and the second light source emits light different from the first LED and the second LED. A phosphor that emits light having a spectrum different from that of the second LED when excited by the emitted light of the two LEDs may be provided.
In this case, compared to the case where the first light source and the second light source are configured using three types of LEDs, the types of LEDs can be reduced.

(15) In the display device for achieving the above object, a direct-type backlight having the first light source and the second light source arranged two-dimensionally may be provided.
In this case, the light use efficiency can be increased as compared with the case where the panel is irradiated with the edge light type backlight.

(16) In the display device for achieving the above object, a data signal for controlling the transmittance of the first subpixel forming unit and the transmittance of the second subpixel forming unit is applied to the panel. A plurality of data lines and a plurality of scanning lines that cross the data lines and to which a selection signal for controlling the change timing of the transmittance of the subpixel forming portion is applied, and the first light source and the A plurality of second light sources are provided and mixed in the arrangement direction of the scanning lines, and the control unit sequentially turns on and turns on the plurality of first light sources at the same cycle as the scanning cycle by the selection signal. The plurality of second light sources may be sequentially turned on and off sequentially in the same cycle as the scanning cycle of the selection signal.
In this case, the image can be displayed brighter than in other cases.

  (17) A panel for achieving the above object is a panel having a plurality of pixel forming portions that are irradiated with a first light source and a second light source having different emission spectra and are two-dimensionally arranged. Is composed of a first sub-pixel forming unit and a second sub-pixel forming unit having a transmission spectrum different from that of the first sub-pixel forming unit, and the first sub-pixel forming in the state irradiated with the first light source. In the state where the first color light is transmitted from the portion and irradiated by the second light source, the second color light is transmitted through the first subpixel formation portion and the second subpixel formation portion is transmitted through the third color light source. Light is transmitted.

  (18) A display device control method for achieving the above object uses first subframe data having one or two color channels and second subframe data having two color channels alternately. While driving the panel, the panel is illuminated by alternately turning on the first light source and the second light source having different emission spectra.

  According to these panel and display device control methods, two subpixel formation portions are required per one pixel formation portion, so that the light use efficiency of the display device can be improved as compared with the conventional field sequential method. it can. In addition, according to the control method of the panel, backlight, and display device, a color image of three-color mixing or four-color mixing can be displayed by time-division display of two subframes, which is a primary stimulus for display colors. Since the transmitted light of three colors or four colors can be divided into two on the time axis by alternately lighting the light sources, it is possible to display a color with higher saturation than the conventional pixel division method while suppressing the subframe frequency.

  According to the invention described above, it is possible to achieve both the light use efficiency of the display device and the saturation of the display color while suppressing the subframe frequency.

(principle)
First, the principle of the present invention will be described with reference to FIGS. 1A and 1B.
1A and 1B are diagrams for explaining a basic concept of a display device according to the present invention. In the figure, L1 and L2 are two types of light sources having different emission spectra, and a first subpixel formation portion P1 and a second subpixel formation portion P2 are arranged corresponding to the respective light sources L1 and L2. Yes. The sub-pixel forming portions P1 and P2 constitute a set and constitute one pixel forming portion. The sub-pixel forming portions P1 and P2 are unit elements for controlling the intensity of transmitted light as one source stimulus necessary for the one pixel forming portion to display an arbitrary chromatic color point. . The pixel forming unit is a unit element that displays an arbitrary chromatic color point. Two types of light sources L1 and L2 emit light having different emission spectra. Two-color transmitted light is radiated in a time-sharing manner from the first sub-pixel forming portion P1, which is one of the two sub-pixel forming portions. For this reason, one pixel formation part can be comprised from two sub pixel formation parts P1 and P2 which are one less than the conventional pixel division method. Therefore, color display with higher utilization efficiency of light emitted from the light source is possible as compared with the conventional pixel division method.

  Further, as shown in FIG. 1A, a monocolor image is displayed by turning on the first light source L1, and a two-color mixed color image is displayed by turning on the second light source L2 as shown in FIG. 1B. An image can be displayed. That is, according to this display device, it is possible to obtain three colors of transmitted light that are the primary stimuli of the display color by halving the time axis by alternately lighting the light sources L1 and L2. This means that a three-color mixed color image can be displayed in two fields. Therefore, a color with higher saturation than that of the conventional pixel division method can be displayed while suppressing the subframe frequency.

  The complementary color relationship originally refers to a relationship between two colors that are equalized to an achromatic color by additive color mixing, but in this specification, the term complementary color is used to mean a looser relationship than the original complementary color relationship. In other words, in this specification, the relationship between complementary colors including a relationship between two colors that establish an original complementary color relationship by regarding a low-saturation color as an achromatic color is referred to as a complementary color relationship. Specifically, two relationships in which the original complementary color relationship is established by regarding the range divided into white as the system color names (Kelly, 1943) of 23 categories as achromatic colors are referred to as complementary color relationships. In this specification, when colors are expressed using color names, the colors are classified by basic color names. Even if there are two colors that can be distinguished as system colors by using modifiers, the system colors that are expressed using the same basic color name do not distinguish between the two colors and the color range is expressed using only the basic color name. Shall.

  When the light emission colors of the two light sources are in a complementary color relationship, it is possible to display a color that is isotropically high in saturation as viewed from the achromatic color, as compared to the case where the light emission colors are not. That is, in this case, a highly saturated color can be displayed with a good balance in the hue direction.

  The first light source emits first emitted light having one or more peak bands; and the second light source emits second emitted light having two or more peak bands; and The transmission band of one sub-pixel forming unit includes the first peak band of the first emitted light and either the first peak band or the second peak band of the second emitted light. And the transmission band of the second subpixel formation part is the first peak band that is not included in the transmission band of the first subpixel formation part among the two peak bands of the second emitted light, or the In the case of including the second peak band, the first color light corresponding to the main component of the first peak band of the first emitted light is switched on because the first light source and the second light source are alternately lit. It is time-divided from light of two colors and light of the third color. Further, in this case, the second emitted light having the first peak band and the second peak band corresponding to the second color main component and the third color main component is the first subpixel forming unit. The second sub-pixel forming unit separates the second color transmitted light and the third color transmitted light. When each of the upper peak bands of the two light sources corresponds to the main component of the transmitted light of one color different from each other, the use efficiency of the light emitted from the first light source and the second light source is higher than when not In addition, since the purity of the transmitted light that is the primary stimulus of the display color is increased, it is possible to display a highly saturated color.

  Note that the peak band of the radiated light is a relatively narrow band in which wavelength components having a clearly high relative intensity are continuous in the wavelength direction, such as the hatched bands in FIGS. 6A, 6D, and 6E. It shall be said. When the peak band is nth (n = 1, 2, 3,...), The maximum relative intensity of the peak band is nth largest among the maximum relative intensities of all peak bands. It shall be the peak bandwidth. The transmission band means a band having a relatively high transmittance with the transmission limit wavelength as a threshold. In the spectral transmittance of the filter, the interval between the threshold wavelength value at which the transmittance is 72% or more and the threshold wavelength value at which the transmittance is 5% or less is called the wavelength inclination width, and the wavelength corresponding to the middle point of the wavelength inclination width is This is called the transmission limit wavelength.

  The wavelength difference between the first peak band of the second emitted light and the second peak band of the second emitted light is the difference between the first peak band of the first emitted light and the second emitted light. When the wavelength difference between the first peak band or the second peak band of the second emitted light is larger than that of the second peak, the purity of the transmitted light that is the primary stimulus of the display color is higher Highly saturated colors can be displayed. The reason is as follows. That is, since the color filter has a considerably wide wavelength inclination width, even if light is separated by two types of color filters, a considerable amount of both of the two types of color filters can be transmitted for some band components of light. . Then, since the purity of the original stimulus of the display color is lowered, the color gamut is narrowed. Therefore, in the configuration in which the transmitted light that is the two primary stimuli is simultaneously emitted from the first subpixel forming unit and the second subpixel forming unit, the first peak of the second emitted light emitted from the second light source It is better that the band and the second highest peak band of the second emitted light are separated as much as possible. Therefore, by designing the emission spectrum of the first light source and the emission spectrum of the second light source as described above, it is possible to display a highly saturated color.

  The peak band of the first emitted light includes any one of wavelengths of R monochromatic light, G monochromatic light, and B monochromatic light, and 2 of the second emitted light which is light emitted by the second light source. One peak band includes one of two wavelengths not included in the peak band of the first light source among wavelengths of the R monochromatic light, the G monochromatic light, and the B monochromatic light. It becomes easy to reproduce faithful colors without narrowing the color gamut. The R monochromatic light, the G monochromatic light, and the B monochromatic light are monochromatic lights of colors that are the primary stimuli determined by the CIE or the de facto standard.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.

(First embodiment)
1. Overall Configuration of Display Device FIG. 2 is a schematic diagram showing the overall configuration of the display device as one embodiment of the present invention. The display device 1 controls an active matrix type liquid crystal panel 13, a data driver 11 and a gate driver 12 for driving the liquid crystal panel 13, a direct type backlight 16, and lighting and extinguishing of the backlight 16. Switching circuits 167 and 168, a controller 10 that controls the data driver 11, the gate driver 12, and the backlight 16, and a power supply unit 17. The controller 10, the data driver 11, the gate driver 12, and the switching circuits 167 and 168 constitute a control unit.

2. Configuration of Panel In the liquid crystal panel 13 shown in FIG. 2, a large number of data lines DL and a large number of scanning lines GL are formed in a lattice pattern. The liquid crystal panel 13 includes a large number of sub-pixel forming portions arranged in one-to-one correspondence with the intersections of the data lines DL and the scanning lines GL.

  FIG. 3 is a schematic diagram showing a cross-sectional structure of the liquid crystal panel 13. In the active matrix type liquid crystal panel 13, a large number of pixel forming portions 20 including a first sub-pixel forming portion 21 and a second sub-pixel forming portion 22 that are adjacent in the horizontal direction are arranged in a two-dimensional matrix. Yes.

  The configurations of the first subpixel forming unit 21 and the second subpixel forming unit 22 are substantially the same except that the transmission spectra of the respective color filters are different from each other. Hereinafter, the stacked structure of the sub-pixel forming portion will be specifically described.

The liquid crystal 135 held by the two glass substrates 132 and 137 is in contact with the two alignment films 134 and 136 and is aligned, for example, substantially perpendicular to the glass substrate 132.
The display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 are opposed to the common electrode 133 with the liquid crystal 135 interposed therebetween. The data line DL corresponding to the first subpixel formation unit 21 is connected to the source of the TFT 261, the drain of the TFT 261 is connected to the display electrode 281 and the gate of the TFT 261 is connected to the scanning line GL (see FIG. 2).

  When a selection signal is applied to the scanning line GL, the source and drain of the TFT 26 are connected, and an electric field having a strength corresponding to the data signal applied to the data line DL is generated between the display electrode 28 and the common electrode 133. Occur. As described above, the orientation of the liquid crystal 135 changes in each subpixel forming portion independently of other adjacent subpixel forming portions in accordance with the strength of the electric field generated between the display electrode 28 and the common electrode 133. When an electric field is generated between the display electrode 28 and the common electrode 133, the linearly polarized light transmitted through the polarizing film 138 bonded to the glass substrate 137 closer to the backlight 16 becomes elliptically polarized light by the liquid crystal 135. The intensity of the light transmitted through the polarizing film 131 bonded to the glass substrate 132 is an intensity corresponding to the value of the data signal applied to the data line DL connected to the display electrode 28.

A first color filter 241 is formed in the opening 231 in the first subpixel formation portion 21 of the black matrix 23. A second color filter 242 is formed in the opening 232 in the second subpixel formation part 22 of the black matrix 23. Since the transmission spectrum of the first color filter 241 provided in the first subpixel forming unit 21 and the transmission spectrum of the second color filter 242 in the second subpixel forming unit 22 are different, the first color observed by the transmission of white light The colors of the filter 241 and the second color filter 242 are different. The transmission spectra of the first subpixel forming unit 21 and the second subpixel forming unit 22 are determined by the transmission spectra of the color filters 241 and 242, the liquid crystal 135, the polarizing films 131 and 138, the glass substrates 132 and 137, and the like. The translucent components other than the color filter such as the liquid crystal 135 are common in the first subpixel forming unit 21 and the second subpixel forming unit 22. Therefore, the difference in the transmission spectrum between the first subpixel forming unit 21 and the second subpixel forming unit 22 is caused by the difference in the transmission spectrum of the first color filter 241 and the transmission spectrum of the second color filter 242. In FIG. 2, the arrangement of the first subpixel formation unit 21 and the second subpixel formation unit 22 is shown by the arrangement of the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22. Has been. That is, the arrangement of the color filters of the liquid crystal panel 13 is a two-color stripe.
In addition, each pixel forming portion is provided with a storage capacitor electrode, and the description thereof is omitted.

3. Backlight Configuration A backlight 16 is provided behind the liquid crystal panel 13. The backlight 16 functions as a surface light source for irradiating the liquid crystal panel 13 via the optical sheet 18. As shown in FIG. 2, the backlight 16 is a direct type in which the first light source LG and the second light source LM are alternately arranged in the arrangement direction of the scanning lines GL. The first light source LG is connected to a switching circuit 167 as a component of the control unit, and can be turned on sequentially and turned off sequentially. The second light source LM is connected to a switching circuit 168 as a component of the control unit, and can be turned on sequentially and turned off sequentially.

  The first light source LG and the second light source LM are both cold cathode fluorescent tubes and have emission spectra different from each other. Cold cathode fluorescent tubes have the advantage of a longer lifetime than hot cathode fluorescent tubes. The emission spectrum of the fluorescent tube is adjusted by mixing phosphors that are radiation sources. For example, the emission spectrum of the fluorescent tube can be designed by laminating the red-colored phosphor, the green-colored phosphor, and the blue-colored phosphor shown in Table 1 below on the inner wall surface of the fluorescent tube.

4). Combination of Color Filter and Light Source Color The color of light transmitted through the color filter is determined by the emission spectrum of the light source and the transmission spectrum of the color filter. The color of the pixel to be formed by one pixel forming unit 20 is the same color by mixing the light transmitted through the first subpixel forming unit 21 and the light transmitted through the second subpixel forming unit 22 at a specific ratio. can do. In order to realize a color display in which three colors are mixed, transmitted light of three colors having different spectra is required. The transmission spectrum of the first color filter 241 of the first subpixel formation unit 21 and the transmission spectrum of the second color filter 242 of the second subpixel formation unit 22 are different, and the emission spectrum of the first light source LG and the emission of the second light source LM. Since the spectrum is different, in principle, four-color mixed color display is possible. That is, when the first light source LG is turned on, a mixture ratio of two colors of light emitted from the first light source LG and transmitted through the first subpixel forming unit 21 and the second subpixel forming unit 22 is applied to the liquid crystal. It can be controlled by voltage. In the state where the second light source LM is turned on, the liquid crystal has a mixing ratio of light of two different colors emitted from the second light source LM and transmitted through the first subpixel forming unit 21 and the second subpixel forming unit 22 respectively. It can be controlled by the applied voltage. Furthermore, in the state where the first light source LG and the second light source LM are turned on, the voltage applied to the liquid crystal can be controlled independently. Since these four colors are mixed by the afterimage, the color display of the four color mixing becomes possible.

  First, the principle of realizing color display in the color gamut indicated by hatching in FIG. 4 using red (R) monochromatic light, green (G) monochromatic light, and blue (B) monochromatic light will be described. In this case, when the emission spectra of the first light source LG and the second light source LM are superimposed, the spectrum shown in FIG. 5A needs to be obtained. Therefore, for example, the emitted light of the first light source LG is set to a green color having a spectrum shown in FIG. 5C, and the emitted light of the second light source LM is set to a magenta color having a spectrum shown in FIG. 5B. Thereby, the intensity of the light transmitted through the green color filter of the emitted light and the intensity of the light transmitted through the color filter of the magenta light can be controlled by liquid crystal in a time-sharing manner. That is, the green component can be separated from the red component and the blue component of the emitted light of the light source without using a color filter. In order to separate magenta radiant light into red transmitted light and blue transmitted light, for example, the first color filter 241 absorbs the blue component and transmits the red component (see FIG. 5D), the second color filter 242 may absorb the red component and transmit the blue component (see FIG. 5E). Thereby, in the state where the second light source LM is lit, the intensity of the red monochromatic transmitted light and the intensity of the blue monochromatic transmitted light can be controlled independently by the voltage applied to the liquid crystal. If at least one of the first color filter 241 and the second color filter 242 has a transmission spectrum that transmits green monochromatic light emitted from the first light source LG (see FIGS. 5D and 5E). In the state where the first light source LG is turned on, the intensity of the green monochromatic transmitted light can be controlled by the voltage applied to the liquid crystal. That is, by using a magenta light source, a green light source, a so-called yellow color filter, and a so-called cyan color filter, the intensity of the red transmitted light, the intensity of the green transmitted light, and the intensity of the blue transmitted light are mutually compared. It can be controlled independently.

  In general, two types of light of different colors are emitted from two light sources, and two kinds of transmitted light of different colors are extracted from one color of light emitted from one of the light sources by two types of color filters. As a result, it is possible to display one color of the three-color mixture, and it is possible to display a color gradation by changing the mixing ratio of the three colors of light according to the voltage applied to the liquid crystal. In order to display a highly saturated color, transmitted light having a spectrum close to monochromatic light, that is, transmitted light having high purity, may be generated by adjusting the emission spectrum of the light source and the transmission spectrum of the color filter. In order to increase the light use efficiency, the emission spectrum of the light source and the transmission spectrum of the color filter may be approximated. In order to widen the color gamut, the emission spectrum of the light source and the transmission spectrum of the color filter may be adjusted so that the area of the triangle on the chromaticity coordinate plane corresponding to the vertexes of the three transmitted light colors is increased. In order to display an achromatic color, the emission spectrum of the light source and the transmission spectrum of the color filter may be adjusted so that the achromatic point is included in the triangle. In order to increase the saturation, the purity of the emitted light from the light source may be increased. In order to display a well-balanced and highly saturated color in the hue direction, the colors of the emitted light from the two light sources may be in a complementary color relationship.

Next, combinations of color filters and light source colors will be described based on a more specific embodiment.
In FIGS. 6A and 7A, the emission spectra of the first light source LG and the second light source LM are indicated by solid lines, respectively. 6 and 7, vertical lines indicate the peak wavelength of the light emitted from the light source, and hatching indicates the peak band of the light emitted from the light source. The first light source LG is a so-called single-wavelength cathode fluorescent tube having a spectral peak in the green band, and the color of the emitted light is green. The second light source LM is a so-called dual-wavelength cathode fluorescent tube having spectral peaks in the red band and the blue band, and the color of the emitted light is magenta.

  FIG. 6B and FIG. 7B both show the transmission spectrum of the first color filter 241. 6C and 7C both show the transmission spectrum of the second color filter 242. FIG. The first color filter 241 includes the green peak band of the first light source LG and the red peak band of the second light source LM in the transmission band and does not include the blue peak band of the second light source LM. The color observed through the white light of the first color filter 241 is yellow. The second color filter 242 includes the green peak band of the first light source LG and the blue peak band of the second light source LM in the transmission band and does not include the red peak band of the second light source LM. The color observed through the white light of the second color filter 242 is cyan (greenish blue). In a context without any misunderstanding, the color of the first color filter 241 can be expressed as yellow and the color of the second color filter 242 can be expressed as cyan.

  Therefore, the green light emitted from the first light source LG is transmitted as green light from the first color filter 241 and the second color filter 242 (see FIGS. 6D and 6E). The magenta light emitted from the second light source LM is transmitted as red light from the first color filter 241 (see FIG. 7D), and is transmitted as blue light from the second color filter 242 (see FIG. 7E).

  If both the transmission bands of the first color filter 241 and the second color filter 242 include the red, green, or blue band, the emitted light of the color including the band is transmitted to the first subpixel forming unit 21. The light can be transmitted from both of the second subpixel forming portions 22. In the case of the above combination, green transmitted light can be obtained from both the first subpixel forming unit 21 and the second subpixel forming unit 22. That is, in this case, the use efficiency of the green light emitted from the first light source LG is doubled compared to the case where the green light is transmitted only from either the first color filter 241 or the second color filter 242. It is possible to control the intensity of green radiated light having high visibility with twice the fine gradation.

  FIG. 6D shows a spectrum of green light that passes through the first sub-pixel forming unit 21 when irradiated by the first light source LG, and FIG. 6E shows the second sub-pixel forming unit 22 when irradiated by the first light source LG. The spectrum of the transmitted green light is shown. Note that the spectrum of the light emitted from the first light source LG and transmitted through the first subpixel forming unit 21 does not necessarily need to match the spectrum of the light transmitted through the second subpixel forming unit. That is, the transmission spectra of the first subpixel forming unit 21 and the second subpixel forming unit 22 should be designed in consideration of matching with the second light source LM. The light transmitted through the first subpixel forming unit 21 and the light transmitted through the second subpixel forming unit 22 are simultaneously perceived by the viewer, and the viewer perceives one color. Adjustment of the white balance is facilitated by adjusting the spectrum of the mixed light so that the color of the light obtained by mixing these two lights is perceived as green. The white balance can be adjusted with high accuracy by increasing the purity of the green mixed light.

  As shown in FIGS. 6B and 6C, the transmission spectrum of the color filter is generally not stepped. For this reason, it is difficult to completely separate light into two components having a small wavelength difference by using two color filters. Therefore, when light having a close wavelength difference between the first peak band having the highest relative light intensity and the second peak band having the second highest relative light intensity is separated by two color filters, the purity of the transmitted light is low. Become. Since the green and blue bands are the closest in the three colors of red, green, and blue, in this embodiment, the green peak band and the blue peak band of the emitted light from the light source are assigned to the first light source LG and the second light source LM. Sorting. In addition, by distributing the peak band of the radiated light in this way, the green peak band with high visibility can be radiated in a time-sharing manner with other peak bands, so that the purity of the green transmitted light can be easily increased. As a result, the white balance can be easily adjusted.

  In order to perform color reproduction faithful to the standardized video signal, the peaks of the emission spectra of the first light source LG and the second light source LM are brought close to the wavelength of the original stimulus of the standard, and the first color It is desirable that the transmission bands of the filter 241 and the second color filter 242 include the peak bands of the emission spectra of the second light source LM and the first light source LG. In order to increase the light use efficiency, the transmission band of the first color filter 241 includes the green peak band of the first light source LG and the red peak band of the second light source LM, and the transmission band of the second color filter 242. The transmission spectrum of the color filter may be designed so that the green peak band of the first light source LG and the blue peak band of the second light source LM are included.

5. Drive circuit A video signal is input to the controller 10 as a component of the control unit. In the case of an interlaced video signal, a frame memory that holds image data (frame data) of one frame is required to display a color image of three colors mixed in one frame in two fields having different color channels. In order to display a three-color mixed color image in two fields, subframe data (first subframe data) having one color channel and subframe data (second subframe data) having two color channels are used. This is because it is necessary to divide the frame data into two) and to supply the two subframe data to the data driver 11 in a time division manner. That is, the controller 10 supplies an RF circuit for generating subframe data based on a video signal, a color conversion matrix calculation circuit, a frame memory, and a synchronization signal to the data driver 11, the gate driver 12, and the switching circuits 167 and 168. Timing controller.

  The data driver 11 as a component of the control unit includes a latch circuit for holding subframe data of 1H or more and applying a data signal for 1H to a plurality of data lines DL. The data signal is generated based on the subframe data and is a signal that, when applied to the display electrode 28, creates a potential difference according to the level of the data signal between the display electrode 28 and the common electrode 133.

  The gate driver 12 as a component of the control unit turns on the TFT 26 for the scanning line GL corresponding to the column in which the display electrodes 28 to which the data signal applied to the data line DL is applied by the data driver 11 are arranged. It is a circuit that applies a selection signal for the purpose.

6). Driving Method FIG. 8 is a table for explaining a driving method of the display device 1. In this embodiment, since a mixed color image is displayed, a green monocolor image is displayed in the first field, and a mixed color image of red and blue is displayed in the second field in the same frame. Using the afterimage effect, the viewer perceives a color image of a mixture of three colors.

  That is, in the first field, the data signal of the green channel is applied from the data driver 11 to all the data lines DL in a state where the first light source LG that emits green light is turned on and the second light source LM is turned off. Therefore, in the first field, green transmitted light having an intensity corresponding to the level of the data signal of the green channel is emitted from both the first subpixel forming unit 21 and the second subpixel forming unit 22. The data signal of the green channel applied to the first subpixel forming unit 21 and the second subpixel forming unit 22 in the first field may be the same or different in one pixel forming unit 20.

  In the second field, in the state where the second light source LM that emits magenta light is turned on and the first light source LG is turned off, the data line DL corresponding to the first sub-pixel forming unit 21 including the yellow first color filter 241 is formed. A red channel data signal is applied from the data driver 11 to the data line 11 and a blue channel data signal is applied from the data driver 11 to the data line DL corresponding to the second subpixel forming unit 22 including the cyan second color filter 242. . Therefore, in the second field, red transmitted light having an intensity corresponding to the level of the data signal of the red channel is emitted from the first sub-pixel forming unit 21, and blue transmitted light having an intensity corresponding to the level of the data signal of the blue channel. Is emitted from the second sub-pixel forming unit 22.

  When the first field and the second field are continuous, the afterimage of the first field and the second field are simultaneously perceived by the viewer. As a result, one color point is generated for each frame and for each pixel forming unit 20. Perceived by the viewer. It should be noted that the combination of the light source and the color channel of the data signal is meaningful, and the first field and the second field may be in any order.

In each field period, a selection signal is sequentially applied from the gate driver 12 to the gate lines GL ₁ , GL ₂ ..., So that a data signal is sequentially applied to the display electrode 28 in each subpixel formation portion. That is, in each sub-pixel forming portion, the data signal held in the display electrode 28 changes by applying a selection signal to the corresponding gate line, and the voltage applied to the liquid crystal changes at that timing. The transmittance changes.

  Only during the period in which the data signal corresponding to any one field of the video signal is held in the display electrode 28 in all the subpixel formation portions, either the first light source LG or the second light source LM corresponding to that field By illuminating all of them, a color display of a mixture of three colors is possible. However, in the period in which the data signal corresponding to any one field of the video signal is held in the display electrode 28 in all the subpixel formation portions, the display electrode 28 holding the data signal corresponding to the two fields. Is considerably shorter than the period in which Accordingly, the first light source LG and the second light source LM corresponding to the field only during the period in which the data signal corresponding to any one field of the video signal is held in the display electrode 28 in all the subpixel formation portions. If any one of these is turned on, the image becomes considerably darker.

  Therefore, in the present embodiment, the first light source LG and the second light source LM are sequentially turned on and off sequentially at the same cycle as the scanning cycle by the selection signal. That is, one of the first light source LG and the second light source LM corresponding to the field is turned on in the vicinity of the column of the sub-pixel formation portion that is in a state where the transmittance corresponding to the field is stable. For example, the first light source LG (or the second light source LM) is sequentially turned on in the vicinity of the column of the sub-pixel formation unit that has transitioned to a stable state in the transmittance corresponding to the field, and the data signal corresponding to the next field is Before being applied to the display electrode 28 in the subpixel formation portion of the column, the first light source LG (or the second light source LM) immediately below the column is sequentially turned off. Such control is performed by synchronous control of the gate driver 12 and the switching circuits 167 and 168 by the controller 10. There is no particular limitation on the number of fluorescent tubes that are simultaneously lit, and for example, all of the first light sources LG or all of the second light sources LM may be lit in a specific period. That is, the length of the lighting period of the first light source LG and the second light source LM is arbitrary.

7). Effect FIG. 9 is a table for explaining the light use efficiency of the display device 1 of the present embodiment. Comparative Example 1 is a conventional pixel division method that displays one color using a white light source and three color filters. Comparative Example 2 is a method of displaying one color using a magenta light source, a green light source, and three color filters. Comparative Example 3 is a conventional field sequential method that displays one color using a red light source, a green light source, and a blue light source.

  When the area on the screen of one pixel formation portion is s, in Comparative Examples 1 and 2, the opening area of the subpixel formation portion that transmits red light, green light, and blue light is 0.3 s. Assume. In the present embodiment, since the number of subpixel forming portions per pixel forming portion 20 is 2/3 times that of Comparative Examples 1 and 2, the opening area of one subpixel is approximately 3 / of that of Comparative Examples 1 and 2. It is about 0.45 s, twice as much. Furthermore, since the green light emitted from the first light source LG is transmitted through both the first subpixel forming unit 21 and the second subpixel forming unit 22, the green light emitted from the first light source LG is The pixel forming portion 20 is opened at a rate of about 0.9 s.

  In Comparative Examples 1 and 2, when the transmittance of the color filter for red light, green light, and blue light is t, in this embodiment, the color filter transmits red light, green light, and blue light. Both rates can be greater than t. This is because there is no need to separate the red peak band and the green peak band of the emitted light with a color filter, and there is no need to separate the blue peak band and the green peak band of the emitted light of the light source with a color filter. Therefore, it is possible to achieve a high transmittance up to a band that should not be transmitted, and the transmittance of the band that should be transmitted accordingly increases. In the present embodiment, the separation of the red peak band and the green peak band and the separation of the blue peak band and the green peak band are all performed on the time axis. This also means that the purity of transmitted light that is the primary stimulus can be increased.

In Comparative Example 1, when the time during which the white light source is turned on in one frame period is u, in Comparative Example 2 and this embodiment, the time for turning on the magenta light source and the time for turning on the green light source are both 1 frame. It becomes about u / 2 in the period.
In Comparative Examples 1 and 2 and the present embodiment, it is assumed that white light is displayed by mixing red transmitted light of light amount r, green transmitted light of light amount g, and blue transmitted light of light amount b. At this time, the amount of transmitted light necessary to display white is r + g + b. When white is displayed in this manner, the light emission amount of the light source in one frame period is as follows.

In Comparative Example 1, the amount of light per unit time (instantaneous amount of light) D that should be emitted from the light source to display white is the red, green, and blue components.
D red = rt / 0.3u
D green = gt / 0.3u
D blue = bt / 0.3u
It becomes. Then, in Comparative Example 1, the light emission amount E of the light source in one frame period necessary for displaying white is a value represented by the following equation.
E = (r + g + b) t / 0.3

In Comparative Example 2, since the instantaneous light amounts D red, D green, and D blue for each of the red, green, and blue components are ½ of the lighting time of the light source,
D red = 2rt / 0.3u
D green = 2gt / 0.3u
D blue = 2bt / 0.3u
It becomes twice that of Comparative Example 1. However, the light emission amount E of the light source in one frame period necessary for displaying white is equal to that of Comparative Example 1 after all since the lighting time of the light source is ½ that of Comparative Example 1.

In the present embodiment, the light emission amount E of the light source in one frame period necessary for displaying the instantaneous light amount D red, D green, D blue, and white for each component of red, green, and blue is as follows: become.
D red = 2rt / 0.45
D green = 2gt / 0.9
D blue = 2bt / 0.45
E = (r + b) t / 0.45 + gt / 0.9

  That is, in this embodiment, the aperture area of the pixel forming unit 20 with respect to red, green, and blue light is about 1.5 times, about 3 times, and about 1.5 times effective compared to Comparative Examples 1 and 2, respectively. Therefore, the light use efficiency is about 1.5 times or more that of Comparative Examples 1 and 2. Therefore, if the power consumption is set to be equal, the present embodiment can achieve brightness (white luminance) of about 1.5 times or more that of Comparative Examples 1 and 2. If the brightness (white luminance) is set equal, the power consumption can be reduced to about 2/3 or less of the first and second comparative examples in this embodiment.

  In the field sequential driving method of Comparative Example 3, the light utilization efficiency is higher than that of the present embodiment. However, in the third comparative example, since one frame is divided into three, when compared at the same frame rate, the subframe frequency is higher than that of the present embodiment.

(Second embodiment)
FIG. 10 shows combinations of color filters and light source colors according to the second embodiment of the present invention. The first color filter 241 of the first subpixel forming unit 21 is a so-called cyan color filter that includes a green band and a blue band in a transmission band and does not include a red band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called red color filter that includes the red band in the transmission band and does not include the green band and the blue band. The first light source LG is a one-wavelength cathode fluorescent tube that emits green light having a green peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits magenta light having a red peak band and a blue peak band.

  In the first field in which the first light source LG that emits green light is turned on, a green channel data signal is applied to the display electrode 281 of the first sub-pixel forming unit 21. Then, a green monocolor image is displayed in the first field. It is desirable to apply a black-equivalent data signal to the display electrode 282 of the second subpixel formation unit 22 so that light does not leak from the second subpixel formation unit 22 in the first field and the green purity does not fall.

  In the second field in which the second light source LM that emits magenta light is turned on, a blue channel data signal is applied to the display electrode 281 of the first subpixel forming unit 21 and the display electrode 282 of the second subpixel forming unit 22 is applied. A red channel data signal is applied to the. Then, in the second field, a mixed color image of red and blue is displayed.

  In the second embodiment, since the second subpixel forming unit 22 is opaque in the first field, the utilization efficiency of the green light emitted from the first light source LG is halved compared to the combination shown in FIG.

(Third embodiment)
FIG. 11 shows combinations of color filters and light source colors according to the third embodiment of the present invention. The first color filter 241 of the first sub-pixel forming unit 21 is a so-called yellow color filter that includes a red band and a green band in a transmission band and does not include a blue band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called blue color filter that includes the blue band in the transmission band and does not include the red band and the green band. The first light source LG is a one-wavelength cathode fluorescent tube that emits green light having a green peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits magenta light having a red peak band and a blue peak band.

  In the first field in which the first light source LG that emits green light is turned on, a green channel data signal is applied to the display electrode 281 of the first sub-pixel forming unit 21. Then, a green monocolor image is displayed in the second field. Since the wavelengths of blue and green are close to each other, light leaks from the second subpixel formation unit 22 in the second field, and the purity of green is likely to drop. Therefore, it is desirable to apply a data signal corresponding to black to the display electrode 282 of the second subpixel forming unit 22 in the second field.

  In the second field in which the second light source LM that emits magenta light is turned on, a red channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 is applied. A blue channel data signal is applied to. Then, in the second field, a mixed color image of red and blue is displayed.

  In the third embodiment, since the second subpixel forming unit 22 is opaque in the first field, the use efficiency of the green light emitted from the first light source LG is halved compared to the combination shown in FIG.

(Fourth embodiment)
FIG. 12 shows combinations of color filters and light source colors according to the fourth embodiment of the present invention. The first color filter 241 of the first subpixel forming unit 21 is a so-called magenta color filter that includes a red band and a blue band in a transmission band and does not include a green band. The second color filter 242 of the second subpixel forming unit 22 is a so-called cyan color filter that includes a green band and a blue band in a transmission band and does not include a red band. The first light source LG is a one-wavelength cathode fluorescent tube that emits blue light having a blue peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits yellow light having a red peak band and a green peak band.

  A blue channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 in the first field in which the first light source LG that emits blue light is turned on. . Then, a blue monocolor image is displayed in the first field.

  In the second field in which the second light source LM that emits yellow light is turned on, a red channel data signal is applied to the display electrode 281 of the first subpixel forming unit 21 and the display electrode 282 of the second subpixel forming unit 22 is applied. A green channel data signal is applied to. Then, in the second field, a mixed color image of red and green is displayed.

  In the fourth embodiment, since the green peak band of the emitted light cannot be extracted in a time-sharing manner from other peak bands, it is difficult to increase the purity of the green compared to the combination shown in FIG. Cheap.

(Fifth embodiment)
FIG. 13 shows combinations of color filters and light source colors according to the fifth embodiment of the present invention. The first color filter 241 of the first subpixel forming unit 21 is a so-called magenta color filter that includes a red band and a blue band in a transmission band and does not include a green band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called green color filter that includes a green band in the transmission band and does not include a red band and a blue band. The first light source LG is a one-wavelength cathode fluorescent tube that emits blue light having a blue peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits yellow light having a red peak band and a green peak band.

  In the first field in which the first light source LG that emits blue light is turned on, a blue channel data signal is applied to the display electrode 281 of the first sub-pixel forming unit 21. Then, a blue monocolor image is displayed in the first field. Since the blue and green wavelengths are close to each other, light leaks from the second subpixel forming portion 22 in the first field, and the purity of blue tends to be lowered. Therefore, it is desirable to apply a data signal corresponding to black to the display electrode 282 of the second subpixel formation unit 22 in the first field.

  In the second field in which the second light source LM that emits yellow light is turned on, a red channel data signal is applied to the display electrode 281 of the first subpixel forming unit 21 and the display electrode 282 of the second subpixel forming unit 22 is applied. A green channel data signal is applied to. Then, in the second field, a mixed color image of red and green is displayed.

  In the fifth embodiment, since the second subpixel forming unit 22 is opaque in the first field, the use efficiency of light emitted from the first light source LG is halved compared to the combination shown in FIG. Further, since the green peak band of the emitted light cannot be extracted in a time-sharing manner from other peak bands, it is difficult to increase the purity of green compared to the combination shown in FIG. 8, and the accuracy of white balance tends to be lowered.

(Sixth embodiment)
FIG. 14 shows combinations of color filters and light source colors according to the sixth embodiment of the present invention. The first color filter 241 of the first subpixel forming unit 21 is a so-called cyan color filter that includes a green band and a blue band in a transmission band and does not include a red band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called red color filter that includes a red band in the transmission band and does not include a green band and a blue band. The first light source LG is a one-wavelength cathode fluorescent tube that emits blue light having a blue peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits yellow light having a red peak band and a green peak band.

  In the first field in which the first light source LG that emits blue light is turned on, a blue channel data signal is applied to the display electrode 281 of the first sub-pixel forming unit 21. Then, a blue monocolor image is displayed in the first field. It is desirable to apply a black-equivalent data signal to the display electrode 282 of the second subpixel formation unit 22 so that light does not leak from the second subpixel formation unit 22 in the first field and the blue purity does not fall.

  In the second field in which the second light source LM that emits yellow light is turned on, a green channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 is applied. A red channel data signal is applied to the. Then, in the second field, a mixed color image of red and green is displayed.

  In the sixth embodiment, since the second subpixel forming unit 22 is opaque in the first field, the use efficiency of the light emitted from the first light source LG is halved compared to the combination shown in FIG. Further, since the green peak band of the emitted light cannot be extracted in a time-sharing manner from other peak bands, it is difficult to increase the purity of green compared to the combination shown in FIG. 8, and the accuracy of white balance tends to be lowered.

(Seventh embodiment)
FIG. 15 shows combinations of color filters and light source colors according to the seventh embodiment of the present invention. The first color filter 241 of the first sub-pixel forming unit 21 is a so-called yellow color filter that includes a red band and a green band in a transmission band and does not include a blue band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called magenta color filter that includes a red band and a blue band in a transmission band and does not include a green band. The first light source LG is a one-wavelength cathode fluorescent tube that emits red light having a red peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits cyan light having a green peak band and a blue peak band.

  In the first field in which the first light source LG that emits red light is turned on, a red channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22. . Then, a red monocolor image is displayed in the first field.

  In the second field in which the second light source LM that emits cyan light is turned on, a green channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 is applied. A blue channel data signal is applied to. Then, in the first field, a mixed color image of green and blue is displayed.

  In the seventh embodiment, since the green peak band of the emitted light cannot be time-divided from other peak bands, it is difficult to increase the purity of green compared to the combination shown in FIG. Cheap. In addition, since the cyan light is separated into the green light and the blue light having similar wavelengths in the second field, the purity of the display color primaries is lower and the color gamut is narrower than the combination shown in FIG.

(Eighth embodiment)
FIG. 16 shows combinations of color filters and light source colors according to the eighth embodiment of the present invention. The first color filter 241 of the first sub-pixel forming unit 21 is a so-called yellow color filter that includes a red band and a green band in a transmission band and does not include a blue band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called blue color filter that includes the blue band in the transmission band and does not include the red band and the green band. The first light source LG is a one-wavelength cathode fluorescent tube that emits red light having a red peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits cyan light having a green peak band and a blue peak band.

  In the first field in which the first light source LG that emits red light is turned on, a red channel data signal is applied to the display electrode 281 of the first sub-pixel forming unit 21. Then, a red monocolor image is displayed in the second field. It is desirable to apply a data signal corresponding to black to the display electrode 282 of the second subpixel formation unit 22 so that light does not leak from the second subpixel formation unit 22 in the first field and the red purity does not fall.

  In the second field in which the second light source LM that emits cyan light is turned on, a green channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 is applied. A blue channel data signal is applied to. Then, in the second field, a mixed color image of green and blue is displayed.

  In the eighth embodiment, since the second subpixel forming unit 22 is opaque in the first field, the use efficiency of light emitted from the first light source LG is halved compared to the combination shown in FIG. Further, since the green peak band of the emitted light cannot be extracted in a time-sharing manner from other peak bands, it is difficult to increase the purity of green compared to the combination shown in FIG. 8, and the accuracy of white balance tends to be lowered. Further, in the second field, cyan light is separated into green light and blue light having a similar wavelength, so that the purity of the original stimulus of the display color is lower and the color gamut is narrower than in the combination shown in FIG.

(Ninth embodiment)
FIG. 17 shows combinations of color filters and light source colors according to the ninth embodiment of the present invention. The first color filter 241 of the first subpixel forming unit 21 is a so-called magenta color filter that includes a red band and a blue band in a transmission band and does not include a green band. The second color filter 242 of the second sub-pixel forming unit 22 is a so-called green color filter that includes a green band in the transmission band and does not include a red band and a blue band. The first light source LG is a one-wavelength cathode fluorescent tube that emits red light having a red peak band. The second light source LM is a two-wavelength cathode fluorescent tube that emits cyan light having a green peak band and a blue peak band.

  In the first field in which the first light source LG that emits red light is turned on, a red channel data signal is applied to the display electrode 281 of the first sub-pixel forming unit 21. Then, a red monocolor image is displayed in the first field. It is desirable to apply a data signal corresponding to black to the display electrode 282 of the second subpixel formation unit 22 so that light does not leak from the second subpixel formation unit 22 in the first field and the red purity does not fall.

  In the second field in which the second light source LM that emits cyan light is turned on, a blue channel data signal is applied to the display electrode 281 of the first subpixel formation unit 21 and the display electrode 282 of the second subpixel formation unit 22 is applied. A green channel data signal is applied to. Then, in the second field, a mixed color image of green and blue is displayed.

  In the ninth embodiment, since the second subpixel forming unit 22 is opaque in the first field, the use efficiency of light emitted from the first light source LG is halved compared to the combination shown in FIG. Further, since the green peak band of the emitted light cannot be extracted in a time-sharing manner from other peak bands, it is difficult to increase the purity of green compared to the combination shown in FIG. 8, and the accuracy of white balance tends to be lowered. In the second field, the color filter separates the cyan light into green light and blue light having similar wavelengths, so that the purity of the primary stimulus of the display color is lower and the color gamut is narrower than in the combination shown in FIG. .

  As described above, the color filter and light source color combinations suitable for using red transmitted light, green transmitted light, and blue transmitted light as the primary stimulus of the display color are described as the second to ninth embodiments. did. Although it is desirable to use red, green, and blue light corresponding to the mechanism of the human cone as the primary stimulus for the display color, the primary stimulus for the display color is not necessarily red, green, or blue light. Also good. However, the color gamut is widened by changing the color of transmitted light, which is the primary stimulus of the display color, to red, green and blue. According to the present invention, various triangles and quadrilaterals that define a color gamut can be formed on the chromaticity coordinate plane by adjusting the emission spectrum of the emitted light of the two types of light sources and the transmission spectrum of the two types of color filters. it can. For example, by displaying a two-color mixed color image in both the first field and the second field, a four-color mixed color display utilizing the afterimage effect is also possible. In this case, a dual wavelength cathode fluorescent tube is used for both the first light source LG and the second light source LM. Further, when the peak band of the emitted light from the light source is included in the transmission band of the color filter, the light use efficiency is increased, but this is not necessarily the case.

(Tenth embodiment)
When fluorescent tubes are used for the two types of light sources, it is desirable that the light sources be alternately arranged in the arrangement direction of the scanning lines GL. However, after the plurality of second light sources LM follow the arrangement direction of the scanning lines GL, A plurality of unit arrays in which one light source LG continues in the array direction of the scan lines may be arrayed in the array direction of the scan lines GL on the entire screen. Further, the backlight need not be a direct type, and may be an edge light type. The fluorescent tube may be a hot cathode fluorescent tube.

(Eleventh embodiment)
An LED may be used as the radiation source for the first light source LG and the second light source LM. Since the LED has a faster luminance response than the cathode fluorescent tube, the image can be displayed brightly. When an LED is used as a radiation source, the emission spectrum as one light source can be designed by the emission spectrum of one or more LEDs and the emission spectrum of one or more phosphors excited by the emitted light of the LED. . Each package that emits light of one color for each package may be used as a unit of light source. Moreover, you may comprise a 1st light source and a 2nd light source with one package which can control the some LED chip mounted in the package independently. In this case, the structure in which the first light source LG and the second light source LM are assembled to the backlight is simplified. Alternatively, a plurality of packages that emit light of different colors from each other may be turned on at the same time to form a single light source unit.

Specifically, for example, a package including an LED chip that emits green light is used as the first light source LG, and an LED chip that combines an LED that emits blue light and a phosphor that emits red light is incorporated. Another package that emits magenta light is referred to as a second light source LM. Further, for example, an LED chip serving as a first light source LG that emits green light and incorporating an LED that emits green light, an LED that emits blue light, and a phosphor that emits red light are incorporated, and magenta. The LED chip as the second light source LM that emits the light can be incorporated in one package so as to be independently controllable. For example, an InGaN-based material is used for an LED that emits blue light or green light. For example, CaAlSiN ₄ : Eu is used as the phosphor that emits red light.

  When an LED is used as a radiation source, since the electrical characteristics of the LED itself vary, the variation in the characteristics of the emitted light of each light source is greater than when a cathode fluorescent tube is used as the light source. Therefore, for example, as shown in FIG. 18, a plurality of (for example, about 5) LED packages that radiate light of the same color and resistors are connected in series as a unit of the first light source LG or the second light source LM. . And the dispersion | variation in the brightness | luminance for every light source can be reduced by connecting in parallel the some 1st light source LG and the some 2nd light source LM in which resistance was adjusted separately.

  When the first light source LG and the second light source LM are configured using LEDs, the first light source LG and the second light source LM are two-dimensionally arranged because the light source has a dot shape. The ratio of the number of the first light sources LG and the number of the second light sources LM arranged per unit area may be constant, and only the first light source LG is arranged in the horizontal direction and only the second light source LM is in the horizontal direction. The rows arranged side by side may be arranged alternately in the vertical direction, or the rows where the first light source LG and the second light source LM are arranged alternately in the horizontal direction may be arranged in the vertical direction.

(Other embodiments)
The arrangement of the first subpixel forming unit 21 and the second subpixel forming unit 22 may be a delta arrangement. Further, the first subpixel forming unit 21 and the second subpixel forming unit 22 may be overshoot driven. Further, the liquid crystal may be controlled so that the alignment is different in one subpixel formation portion. Further, the panel may be a transmissive type, and may not be a hold type, may be a simple matrix type, or may control the transmissivity of the subpixel formation portion other than the liquid crystal. Further, a black level data signal may be applied to the display electrode 28 between fields or frames. Furthermore, the present invention can be applied to a driving method for time-dividing one frame into 2n (N = 0, 1, 2,...) Fields and performing color display. For example, the present invention can be implemented in combination with a double speed driving method. Is possible.
It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

Explanatory drawing which shows the outline | summary of this invention. The schematic diagram concerning embodiment of this invention. The typical sectional view concerning the embodiment of the present invention. The chromaticity diagram concerning the embodiment of the present invention. The figure which shows the spectrum concerning embodiment of this invention. The figure which shows the spectrum concerning embodiment of this invention. The figure which shows the spectrum concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The table | surface concerning embodiment of this invention. The circuit diagram concerning the embodiment of the present invention.

Explanation of symbols

1: Display device, 10: Controller, 11: Data driver, 12: Gate driver, 13: Liquid crystal panel, 16: Backlight, 17: Power supply unit, 18: Optical sheet, 20: Pixel forming unit, 21: First sub Pixel forming part, 22: second sub-pixel forming part, 23: black matrix, 28: display electrode, 131: polarizing film, 132: glass substrate, 133: common electrode, 134: alignment film, 135: liquid crystal, 137: glass Substrate, 138: Polarizing film, 167: Switching circuit, 168: Switching circuit, 231: Opening, 232: Opening, 241: First color filter, 242: Second color filter, 281: Display electrode, 282: Display electrode DL data line, GL: scanning line, LG: first light source, LM: second light source

Claims (18)

A panel having a plurality of pixel forming units arranged two-dimensionally, a first light source that irradiates the pixel forming unit, a second light source that irradiates the pixel forming unit, the first light source, the second light source, and the A display unit comprising a control unit for controlling the panel,
The first light source and the second light source have different emission spectra;
The pixel forming unit includes:
A first sub-pixel forming unit that emits a first color transmitted light when irradiated by the first light source and a second color transmitted light when irradiated by the second light source;
A second subpixel forming unit that has a transmission spectrum different from that of the first subpixel forming unit and emits transmitted light of a third color when illuminated by the second light source;
The control unit alternately turns on the first light source and the second light source, and is irradiated by the transmittance of the first sub-pixel forming unit irradiated by the first light source and the second light source. Independently controlling the transmittance of the first sub-pixel forming portion and the transmittance of the second sub-pixel forming portion irradiated by the second light source,
Display device.
The color of the first emitted light that is the light emitted from the first light source and the color of the second emitted light that is the light emitted from the second light source are in a complementary color relationship.
The display device according to claim 1. The first light source emits first emitted light having one or more peak bands;
The second light source emits second emitted light having two or more peak bands;
The transmission band of the first sub-pixel forming unit includes a first peak band of the first emitted light and any one of the first peak band or the second peak band of the second emitted light. Including
The transmission band of the second subpixel formation part is the first peak band or the second peak that is not included in the transmission band of the first subpixel formation part among the peak band of the second radiation light. Including bandwidth,
The display device according to claim 1. The wavelength difference between the first peak band of the second emitted light and the second peak band of the second emitted light is the difference between the first peak band of the first emitted light and the second emitted light. Greater than the wavelength difference between the first peak band or the second peak band of the second emitted light,
The display device according to claim 3. The peak band of the first emitted light that is the light emitted from the first light source includes any one of wavelengths of R monochromatic light, G monochromatic light, and B monochromatic light,
The two peak bands of the second radiated light that is the light emitted from the second light source are not included in the peak bands of the first light source among the wavelengths of the R monochromatic light, the G monochromatic light, and the B monochromatic light. Contains one each of two wavelengths,
The display device according to claim 1. The first color is green;
The display device according to claim 1. The color of the first emitted light, which is the light emitted from the first light source, is green.
The display device according to claim 1. The second sub-pixel forming unit has a transmission spectrum that transmits light of the same color as the first color when irradiated by the first light source.
The display device according to claim 1. The first light source is a cathode fluorescent tube provided with a phosphor of one wavelength as a radiation source,
The second light source is a cathode fluorescent tube equipped with a two-wavelength phosphor as a radiation source.
The display device according to claim 1. A direct backlight having the first light source and the second light source;
The display device according to claim 1. The panel intersects the data lines with a plurality of data lines to which a data signal for controlling the transmittance of the first sub-pixel forming unit and the transmittance of the second sub-pixel forming unit is applied. A plurality of scanning lines to which a selection signal for controlling the change timing of the transmittance of the pixel forming portion is applied,
A plurality of the first light sources and the second light sources are provided and mixed in the arrangement direction of the scanning lines, respectively.
The control unit sequentially turns on and turns off the plurality of first light sources sequentially at the same cycle as the scanning cycle by the selection signal and sequentially turns on the plurality of second light sources at the same cycle as the scanning cycle by the selection signal. And turn off sequentially,
The display device according to claim 10. The first light source and the second light source are alternately arranged,
The display device according to claim 1. The first light source includes one type of LED chip,
The second light source includes two types of LED chips with different colors.
The display device according to claim 1. The first light source includes a first LED,
The second light source includes a second LED that emits light different from that of the first LED, and a phosphor that emits light having a spectrum different from that emitted from the second LED when excited by the emitted light of the second LED. Comprising
The display device according to claim 1. A direct-type backlight having the first light source and the second light source arranged two-dimensionally;
The display device according to claim 1. The panel intersects the data lines with a plurality of data lines to which a data signal for controlling the transmittance of the first sub-pixel forming unit and the transmittance of the second sub-pixel forming unit is applied. A plurality of scanning lines to which a selection signal for controlling the change timing of the transmittance of the pixel forming portion is applied,
A plurality of the first light sources and the second light sources are provided and mixed in the arrangement direction of the scanning lines, respectively.
The control unit sequentially turns on and turns off the plurality of first light sources sequentially at the same cycle as the scanning cycle by the selection signal and sequentially turns on the plurality of second light sources at the same cycle as the scanning cycle by the selection signal. And turn off sequentially,
The display device according to claim 1. A panel having a plurality of pixel formation portions irradiated two-dimensionally by a first light source and a second light source having different emission spectra,
The pixel forming unit includes:
A first sub-pixel forming portion;
A second subpixel forming unit having a transmission spectrum different from that of the first subpixel forming unit,
In the state irradiated by the first light source, light of the first color is transmitted from the first sub-pixel forming portion,
In the state irradiated by the second light source, the second color light is transmitted through the first subpixel formation portion and the third color light is transmitted through the second subpixel formation portion.
panel. The first sub-frame data having one or two color channels and the second sub-frame data having two color channels are alternately used to drive the panel, and the first light source and the first light source having different emission spectra are used. Illuminating the panel by alternately lighting two light sources,
Display device control method.

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