JP4139344B2 - Display device - Google Patents

Description

  The present invention relates to a display device capable of performing multi-primary color display using light sources having different emission wavelength ranges.

  Conventionally, white cold-cathode tubes and white light-emitting diodes have been used for light sources such as lighting fixtures, guide plates with built-in light sources, and backlight devices for liquid crystal displays. Since the emission wavelength spectrum of the white cold cathode tube is wide, there is a problem that the color purity is low and the color reproduction range is narrow.

  In addition, since white light emitting diodes obtain white light by irradiating light from blue light emitting diodes to yellow phosphors, when irradiating liquid crystal panels equipped with red, green and blue color filters, color filters Since the transmission wavelength spectrum of the light source does not match the emission wavelength spectrum of the light source, not only the light use efficiency is low, but also the color reproduction range is narrow.

  Further, in a white light emitting diode in which red, green and blue light emitting diodes are accommodated in one package, it is necessary to make each element small in order to accommodate the light emitting diode elements of each color in one package. A high emission intensity cannot be obtained. In particular, large displays and outdoor lighting fixtures cannot be used because they need to have high brightness.

  In order to solve the above-described problems, a method of using a high-intensity light-emitting diode in which each emission color is independent has been considered, and the light-emitting diodes having high color purity for each color of red, green, and blue are used as the light source of the backlight. Studies have been made to realize a display with a wide color reproduction range.

  In addition, in order to perform multi-primary color display that can expand the color reproduction range than the three primary colors, the number of emission colors of the high-intensity light-emitting diode is increased, and further, the number of color filters provided in the liquid crystal display is increased. Further consideration is being given to higher image quality.

Further, multi-primary color display by time division has been studied. For example, Japanese Patent Application Laid-Open No. 2002-149129 (Patent Document 1) includes a necessary number of light sources whose emission colors are red, green, and blue, respectively, and liquid crystal A pixel that transmits red light and green light and a pixel that transmits green light and blue light are arranged on the panel, and one frame for displaying an entire color image is divided into two subframes. A color image display device that easily realizes three primary color display by time-division driving by emitting a green light source in the first subframe and emitting a red light source and a blue light source in the second subframe has been proposed. .
JP 2002-149129 A

  However, the conventional display method described above has the following problems. In other words, in order to perform multi-primary color display, if an attempt is made to arrange a large number of light sources having different emission colors, the light-emitting device needs to have four or more types of light sources having different emission colors. As a result, the distance between the light sources having the luminescent colors increases, and the luminance unevenness and the color unevenness of the illumination light increase. In addition, since the types of pixels also increase, the light transmittance decreases, resulting in a decrease in luminance or an increase in power consumption.

  Also, in the method disclosed in Patent Document 1, since the three primary colors are displayed in a time-divided manner in one frame period and two subframe periods, the color reproduction range is narrower than that in the four primary colors display. In addition, since three types of light sources of red, green, and blue are used, the arrangement of the light sources of the same emission color cannot be made dense, resulting in luminance unevenness and color unevenness. Furthermore, when the emission color of the light source increases, it is necessary to control the light emission for each color light source, and the light emission control of the light source becomes complicated.

  The present invention has been made in view of the above problems, and by performing four primary color display using two types of light sources, a display device capable of improving the color reproduction range and reducing luminance unevenness and color unevenness. Is to provide.

  The first invention of the present application includes a first light source and a second light source having different emission wavelength regions, a first wavelength conversion means for converting the wavelength of at least part of light from the first light source, and the second light source. In the display device including the second wavelength conversion unit that converts the wavelength of at least a part of the light and the light modulation unit that modulates the light intensity according to the video signal, the light modulation unit includes a plurality of images. The sub-images are controlled so as to switch the light emission of the first light source and the second light source corresponding to the sub-image.

  In a second invention of the present application, the light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated, and the first pixel is light in an emission wavelength region of the first light source. Intensity and light intensity in the emission wavelength region of the second light source are modulated, and the second pixel converts the light intensity in the wavelength region converted by the first wavelength conversion unit and the second wavelength conversion unit. The light intensity in the wavelength region is modulated.

  According to a third invention of the present application, the light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated, and the first pixel is light in an emission wavelength region of the first light source. Intensity and light intensity in the wavelength region converted by the second wavelength conversion unit are modulated, and the second pixel emits light in the wavelength region converted by the first wavelength conversion unit and emission of the second light source. The light intensity in the wavelength region is modulated.

  A fourth invention of the present application is characterized in that wavelength regions of light modulated by the first pixel are a blue wavelength region and a red wavelength region.

  The fifth invention of the present application further includes third wavelength conversion means for converting the wavelength of at least part of the light from the second light source into a wavelength region different from the wavelength region converted by the second wavelength conversion means. It is characterized by having.

  In a sixth invention of the present application, the light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated, and the first pixel is light in an emission wavelength region of the first light source. Modulating the intensity and the light intensity in the wavelength region converted by the third wavelength conversion means, and the second pixel converts the light intensity in the wavelength region converted by the first wavelength conversion means and the second wavelength conversion means. It modulates the light intensity in the wavelength region converted by.

  In a seventh invention of the present application, the light modulating means includes a first pixel and a second pixel having different wavelength regions of light to be modulated, and the first pixel is light in an emission wavelength region of the first light source. Modulating the intensity and the light intensity in the wavelength region converted by the second wavelength conversion means, and the second pixel is converted into the light intensity in the wavelength region converted by the first wavelength conversion means and the third wavelength conversion means. It modulates the light intensity in the wavelength region converted by.

  The eighth invention of the present application is characterized in that wavelength regions of light modulated by the first pixel are a blue wavelength region and a red wavelength region.

  The ninth invention of the present application further includes fourth wavelength conversion means for converting the wavelength of at least part of light from the first light source into a wavelength region different from the wavelength region converted by the first wavelength conversion means. It is characterized by having.

  According to a tenth aspect of the present invention, the light modulation unit includes a first pixel and a second pixel having different wavelength regions of light to be modulated, and the first pixel has a wavelength converted by the fourth wavelength conversion unit. The light intensity of the region and the light intensity of the wavelength region converted by the third wavelength conversion unit are modulated, and the second pixel has the light intensity of the wavelength region converted by the first wavelength conversion unit, and the second The light intensity in the wavelength region converted by the wavelength conversion means is modulated.

  In an eleventh aspect of the present invention, the light modulating unit includes a first pixel and a second pixel having different wavelength regions of light to be modulated, and the first pixel has a wavelength converted by the fourth wavelength converting unit. The light intensity of the region and the light intensity of the wavelength region converted by the second wavelength conversion unit are modulated, and the second pixel has the light intensity of the wavelength region converted by the first wavelength conversion unit, and the third The light intensity in the wavelength region converted by the wavelength conversion means is modulated.

  A twelfth aspect of the present invention is characterized in that wavelength regions of light modulated by the first pixel are a blue wavelength region and a red wavelength region.

  A thirteenth invention of the present application is characterized in that the first light source or the second light source is a light emitting diode.

  A fourteenth invention of the present application is characterized in that an emission wavelength region of the first light source is a blue wavelength region.

  A fifteenth aspect of the present invention is characterized in that an emission wavelength region of the second light source is an ultraviolet wavelength region.

  A sixteenth aspect of the present invention is characterized in that an emission wavelength region of the first light source is an ultraviolet wavelength region.

  A seventeenth invention of the present application is characterized in that the first wavelength conversion means and / or the second wavelength conversion means and / or the third wavelength conversion means and / or the fourth wavelength conversion means is a phosphor. To do.

  The eighteenth invention of the present application is characterized in that the wavelength region converted by the second wavelength converting means is a red wavelength region.

  A nineteenth invention of the present application is characterized in that the light modulating means is a liquid crystal panel.

  According to the display device of the present invention, the first light source and the second light source having different emission wavelength regions, the first wavelength conversion means for converting the wavelength of at least part of the light from the first light source, and the second light source Second wavelength conversion means for converting the wavelength of at least part of the light, and forming one image from a plurality of sub-images, and corresponding to the sub-images, the first light source and the second light source By switching the light emission, even when four primary colors are displayed, the type of light source can be two types, and by arranging the same type of light source densely, it becomes easier to mix the light of each wavelength region, Luminance unevenness and color unevenness can be reduced.

  According to the display device of the present invention, the first pixel of the light modulation unit modulates the light intensity of the light emission wavelength region of the first light source and the light intensity of the light emission wavelength region of the second light source. Since the two pixels modulate the light intensity in the wavelength region converted by the first wavelength conversion means and the light intensity in the wavelength region converted by the second wavelength conversion means, multi-primary color display can be performed with a small number of types of pixels. Thus, the display resolution can be increased to achieve high image quality, or when the resolution is the same, the aperture ratio of the pixel can be improved.

  According to the display device of the present invention, the first pixel of the light modulation unit modulates the light intensity of the light emission wavelength region of the first light source and the light intensity of the wavelength region converted by the second wavelength conversion unit, thereby modulating the light. The second pixel of the means modulates the light intensity of the wavelength region converted by the first wavelength conversion means and the light intensity of the light emission wavelength region of the second light source, so that multi-primary color display can be performed with a small number of types of pixels. Thus, the display resolution can be increased to achieve high image quality, or when the resolution is the same, the aperture ratio of the pixel can be improved.

  According to the display device of the present invention, it further includes third wavelength conversion means for converting the wavelength of at least part of the light from the second light source into a wavelength region different from the wavelength region converted by the second wavelength conversion means. This makes it possible to increase the number of primary colors of illumination light without increasing the types of light sources.

  According to the display device of the present invention, the first pixel of the light modulation unit modulates the light intensity of the light emission wavelength region of the first light source and the light intensity of the wavelength region converted by the third wavelength conversion unit, thereby modulating the light. The second pixel of the means modulates the light intensity of the wavelength region converted by the first wavelength conversion means and the light intensity of the wavelength region converted by the second wavelength conversion means, so that multi-primary color display can be performed with a small number of types of pixels. It is possible to increase the display resolution and realize high image quality, or when the resolution is the same, the aperture ratio of the pixel can be improved.

  According to the display device of the present invention, the first pixel of the light modulation unit modulates the light intensity of the light emission wavelength region of the first light source and the light intensity of the wavelength region converted by the second wavelength conversion unit, thereby modulating the light. The second pixel of the means modulates the light intensity of the wavelength region converted by the first wavelength conversion means and the light intensity of the wavelength region converted by the third wavelength conversion means, so that multi-primary color display can be performed with a small number of types of pixels. It is possible to increase the display resolution and realize high image quality, or when the resolution is the same, the aperture ratio of the pixel can be improved.

  According to the display device of the present invention, the fourth wavelength conversion unit that converts the wavelength of at least a part of the light from the first light source into a wavelength region different from the wavelength region converted by the first wavelength conversion unit is further provided. Thus, the number of primary colors of illumination light can be further increased without increasing the types of light sources.

  According to the display device of the present invention, the first pixel of the light modulator modulates the light intensity in the wavelength region converted by the fourth wavelength converter and the light intensity in the wavelength region converted by the third wavelength converter. The second pixel of the light modulation means modulates the light intensity in the wavelength region converted by the first wavelength conversion means and the light intensity in the wavelength region converted by the second wavelength conversion means. Primary color display can be performed, and the display resolution can be increased to achieve high image quality, or when the resolution is the same, the aperture ratio of the pixel can be improved.

  According to the display device of the present invention, the first pixel of the light modulator modulates the light intensity in the wavelength region converted by the fourth wavelength converter and the light intensity in the wavelength region converted by the second wavelength converter. Since the second pixel of the light modulation means is configured to modulate the light intensity in the wavelength region converted by the first wavelength conversion means and the light intensity in the wavelength region converted by the third wavelength conversion means, It is possible to perform multi-primary color display with pixels, and display quality can be improved by increasing the display resolution, or when the resolution is the same, the aperture ratio of the pixels can be improved.

  According to the display device of the present invention, since the wavelength regions of the light modulated by the first pixel are the blue wavelength region and the red wavelength region, the light of each wavelength region included in the illumination light can be easily separated for each pixel. Thus, the color purity of the light to be displayed can be increased, and a display with improved color reproducibility can be realized.

  According to the display device of the present invention, since the first light source or the second light source is constituted by a light emitting diode, not only the selection of the light emission wavelength region of the light source is facilitated, but also the light emission wavelength spectrum is steep. Illumination light with high color purity can be obtained.

  According to the display device of the present invention, the emission wavelength region of the first light source is set to the blue wavelength region so that it can be used not only as a primary color for display but also easily converted into another wavelength region by the wavelength conversion means. It becomes possible.

  According to the display device of the present invention, by setting the emission wavelength region of the second light source to the ultraviolet wavelength region, energy is increased by shortening the wavelength of light, and wavelength conversion to the longer wavelength side is facilitated. Can do.

  According to the display device of the present invention, by setting the emission wavelength region of the first light source to the ultraviolet wavelength region, energy is increased by shortening the wavelength of the light, and wavelength conversion to the longer wavelength side is facilitated. Can do.

  According to the display device of the present invention, the first wavelength conversion unit and / or the second wavelength conversion unit and / or the third wavelength conversion unit and / or the fourth wavelength conversion unit is configured by a phosphor. It is possible to easily realize the wavelength conversion means.

  According to the display device of the present invention, it is possible to obtain light in the red wavelength region with high efficiency by setting the wavelength region converted by the first wavelength conversion unit or the second wavelength conversion unit to the red wavelength region. .

  According to the display device of the present invention, by using a liquid crystal panel as the light modulation means, it is possible to easily realize the light modulation means for modulating light in each wavelength region.

(Embodiment 1)
Hereinafter, a display device according to Embodiment 1 of the present invention will be described in detail with reference to FIGS. 1 to 6. The configuration in each drawing is exaggerated for easy understanding, and is different from the actual size and interval.

  FIG. 1 is an explanatory view schematically showing a side cross section of the first embodiment of the present invention. The display device of this embodiment includes a B light source 101 (first light source) that emits light in the blue wavelength region and a G light source 102 (second light source) that emits light in the green wavelength region from a short wavelength. Each of the light sources 101 and 102 is preferably composed of a light emitting diode, because the wavelength of the emitted light can be easily selected by selecting and fabricating the structure and material of the light emitting element.

  In addition, a phosphor film 104 is provided on each light source side of the diffusion plate 103 irradiated with light from the B light source 101 and the G light source 102. The phosphor film 104 is a phosphor (first wavelength converting means) that converts light from the B light source 101 (hereinafter referred to as “B light”) into light in a green wavelength region having a longer wavelength (hereinafter referred to as G2 light). And a phosphor (second wavelength conversion means) that converts light from the G light source 102 (hereinafter referred to as G1 light) into light in the red wavelength region (hereinafter referred to as R light).

  Here, by controlling the film thickness of the phosphor film 104, the rate at which the light from each light source is converted by the phosphor film 104 can be adjusted. The phosphor may be an organic phosphor, an inorganic phosphor, or a mixture of organic and inorganic. Further, a phosphor may be mixed in the diffusion plate 103, and the same effect can be obtained by arranging a sheet containing or coated with the phosphor.

  A liquid crystal panel 105 (light modulation means) is disposed on the side of the diffusion plate 103 opposite to each light source. Although not shown, it is possible to improve the light use efficiency by disposing an optical sheet such as a diffusion sheet or a prism sheet between the diffusion plate 103 and the liquid crystal panel 105.

  As shown in FIG. 2, the liquid crystal panel 105 according to the present embodiment includes two types of pixels each including a magenta filter that transmits B light and R light and a green filter that transmits G1 light and G2 light. Composed. That is, one pixel is composed of two types of sub-pixels each having a magenta filter and a green filter.

  Here, when the B light source 101 is in a light emission state and the G light source 102 is in a non-light emission state, part of the B light emitted from the B light source 101 is converted into G2 light by the phosphor film 104. Therefore, the light applied to the liquid crystal panel 105 is a mixed light of the B light that has not been converted by the phosphor film 104 and the G2 light that has been converted by the phosphor film 104. The wavelength spectrum of the mixed light at this time is as shown in FIG.

  On the other hand, when the B light source 101 is not emitting light and the G light source 102 is emitting light, part of the G1 light emitted from the G light source 102 is converted into R light by the phosphor film 104. Therefore, the light applied to the liquid crystal panel 105 is a mixed light of the G1 light that has not been converted by the phosphor film 104 and the R light that has been converted by the phosphor film 104. The wavelength spectrum of the mixed light at this time is as shown in FIG.

  As described above, the light applied to the liquid crystal panel 105 is in two states shown in FIGS. 3A and 3B, and the transmission wavelength characteristics of the color filter of the liquid crystal panel 105, the wavelength spectrum of the irradiated light, and the like. Has a relationship as shown in FIG. That is, the B light passes through the magenta filter, and the G2 light excited by the B light passes through the green filter. The G1 light passes through the green filter, and the R light excited by the G1 light passes through the magenta filter.

  Therefore, it is possible to irradiate the liquid crystal panel 105 with light of the four primary colors by switching and controlling the light source 101 that emits B light and the light source 102 that emits G1 light by a method described later. Here, as shown in FIG. 4B, the color filter included in the liquid crystal panel 105 is composed of a cyan filter that transmits B light and G1 light, and a yellow filter that transmits G2 light and R light. However, it is necessary to transmit the G1 light and the G2 light with different color filters. If the wavelength of the G1 light and the wavelength of the G2 light are close and cannot be sufficiently separated, the color purity is lowered. As described above, it is preferable to use magenta and green color filters.

  Next, the light emission timings of the light sources 101 and 102 in this embodiment will be described. In this embodiment, a case where an image of 60 frames is displayed per second will be described, and one frame is divided into two subframes to display an image. That is, as shown in FIG. 5, one subframe period is 1/120 seconds, the first subframe is a period from 0 seconds to 1/120 seconds, and the second subframe is 1/120 to 2/120 seconds. This period is repeated.

  In the first sub-frame, each pixel of the liquid crystal panel 105 displays a sub-image corresponding to the B light and the G2 light. That is, the sub-pixel provided with the magenta filter performs display for B light, and the sub-pixel provided with the green filter performs image display for G2 light. The light emission state of the light source at this time is such that the B light source 101 is in a light emission state and the G light source 102 is in a non-light emission state. That is, the liquid crystal panel 105 is irradiated with B light emitted from the B light source 101 and G2 light excited by the B light and emitted from the phosphor. Accordingly, in the first sub-frame, images corresponding to B and G2 are displayed by the liquid crystal panel 105.

  In the second sub-frame, each pixel of the liquid crystal panel 105 displays a sub-image corresponding to G1 light and R light. That is, the sub-pixel provided with the magenta filter performs display for R light, and the sub-pixel provided with the green filter performs image display for G1 light. The light emission state of the light source at this time is such that the B light source 101 is in a non-light emission state and the G light source 102 is in a light emission state. In other words, the G1 light emitted from the G light source 102 and the R light excited by the G1 light and emitted from the phosphor are irradiated onto the liquid crystal panel 105. Therefore, in the second subframe, the liquid crystal panel 105 displays an image corresponding to R and G1.

  Here, a system that realizes the above-described operation can be realized by using, for example, a configuration as shown in FIG. The video data sent to the display device is converted into an image for the first subframe and an image for the second subframe corresponding to the display color in each subframe by the image conversion means 111. That is, it is converted into a sub-image corresponding to B and G2, and a sub-image corresponding to R and G1. The converted image data is stored in the buffer 112 and the buffer 113, respectively, and the image data to be displayed is transmitted to the liquid crystal driving circuit 115 by the signal from the timing control circuit 114, and the image is displayed on the liquid crystal panel 115.

  In addition, the timing control circuit 114 transmits a signal to the LED drive circuit 116 corresponding to the sub-image displayed on the liquid crystal panel 115 to control the light emission timing of each of the light sources 101 and 102 of the backlight. That is, when the display state of the liquid crystal panel 105 corresponds to B and G2, control is performed so that the B light source 101 is in a light emission state and the G light source 102 is in a non-light emission state. Here, the light emission of the light sources 101 and 102 does not always have to be in the light emission state, and is controlled to emit light when the response of the liquid crystal is almost completed, that is, can be modulated to a desired gradation. By emitting light in such a state, a more suitable display is possible.

  As described above, in the present embodiment, two sub-images are generated from one image and displayed on the liquid crystal panel 105 in a time-sharing manner, and the B light source 101 is matched with the display timing of each sub-image. In addition, the emission of the G1 light source 102 is switched, and the display light in the first subframe and the second subframe is temporally mixed, whereby four primary colors can be displayed. That is, the liquid crystal panel 105 is driven and controlled so that one image is formed from two sub-images having different primary colors, and two types of light emission / non-light emission of the B light source 101 and the G light source 102 according to the display timing of the sub-image. Multi-primary color display can be realized by switching the emission.

  In addition, if the four primary color display is realized by the conventional method, light from four types of light sources having different emission wavelengths has to be mixed, and there is a problem in that luminance unevenness and color unevenness occur. In the present embodiment, there are two types of emission wavelengths of the light source, and it is only necessary to mix the light from the two types of light sources, and the light sources can be arranged densely, thereby reducing luminance unevenness and color unevenness. It becomes possible.

(Embodiment 2)
Hereinafter, the display device according to Embodiment 2 of the present invention will be described in detail with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part same as Embodiment 1 of the said invention, and the description is abbreviate | omitted.

  FIG. 7 is an explanatory view schematically showing a side cross section of the second embodiment of the present invention. The display device of this embodiment includes a UV light source 201 (second light source) that emits light in the ultraviolet wavelength region and a B light source 202 (first light source) that emits light in the blue wavelength region. A phosphor film 203 is provided on each light source side of the diffusion plate 103 irradiated with light from the UV light source 201 and the B light source 202.

  The phosphor film 203 is a phosphor (third wavelength conversion means) that converts light from the UV light source 201 (hereinafter referred to as UV light) into light in a green wavelength region from a short wavelength (hereinafter referred to as G1 light). A phosphor (second wavelength converting means) that converts UV light into light in the red wavelength region (hereinafter referred to as R light) and light from the B light source 202 (hereinafter referred to as B light) from a longer wavelength. And a phosphor (first wavelength converting means) that converts light into green wavelength region light (hereinafter referred to as G2 light).

  The liquid crystal panel in this embodiment can use the same liquid crystal panel 105 as used in the first embodiment, and transmits a magenta filter that transmits B light and R light, and transmits G1 light and G2 light. And two types of pixels each having a green filter.

  Here, when the UV light source 201 is in a light emission state and the B light source 202 is in a non-light emission state, the UV light emitted from the UV light source 201 is converted into G1 light and R light by the phosphor film 203. Therefore, the light irradiated to the liquid crystal panel 105 becomes a mixed light of the G1 light and the R light converted by the phosphor film 203.

  On the other hand, when the UV light source 201 is not emitting light and the B light source 202 is emitting light, part of the B light emitted from the B light source 202 is converted into G2 light by the phosphor film 203. Accordingly, the light applied to the liquid crystal panel 105 is a mixed light of the B light that has not been converted by the phosphor film 203 and the G2 light that has been converted by the phosphor film 203.

  As described above, by providing the two types of light sources 201 and 202 and the phosphor film 203, the liquid crystal panel 105 can be irradiated with light of four types of wavelengths in the visible region. That is, by irradiating the phosphor film 203 uniformly with light from two types of light sources, that is, the UV light source 201 and the B light source 202, it is possible to obtain four primary colors of illumination light with reduced luminance unevenness and color unevenness. .

  Next, the light emission timings of the light sources 201 and 202 in this embodiment will be described. Also in this embodiment, a case where an image of 60 frames is displayed per second will be described, and one frame is divided into two subframes to display an image. That is, as shown in FIG. 8, one subframe period is 1/120 second, the first subframe is from 0 second to 1/120 second, and the second subframe is from 1/120 to 2/120 second. This period is repeated.

  In the first sub-frame, each pixel of the liquid crystal panel 105 displays a sub-image corresponding to G1 light and R light. That is, the sub-pixel provided with the magenta filter performs display for R light, and the sub-pixel provided with the green filter performs display for G1 light. The light emission state of the light source at this time is such that the UV light source 201 is in a light emission state and the B light source 202 is in a non-light emission state. That is, the liquid crystal panel 105 is irradiated with G1 light and R light that are excited by UV light and emitted from the phosphor. Therefore, in the first sub-frame, images corresponding to G1 and R are displayed by the liquid crystal panel 105.

  In the second sub-frame, each pixel of the liquid crystal panel 105 displays a sub-image corresponding to B light and G2 light. That is, the sub-pixel including the magenta filter performs display for B light, and the sub-pixel including the green filter performs display for G2 light. The light emission state of the light source at this time is such that the UV light source 201 is in a non-light emission state and the B light source 202 is in a light emission state. That is, the liquid crystal panel 105 is irradiated with B light emitted from the B light source 202 and G2 light emitted from the phosphor excited by the B light. Accordingly, in the second subframe, images corresponding to B and G2 are displayed by the liquid crystal panel 105.

  As described above, the display colors in the first subframe and the second subframe are temporally mixed to display four primary colors. That is, the liquid crystal panel 105 is driven and controlled so that one image is formed from two sub-images having different primary colors, and two types of light emission / non-light emission of the UV light source 201 and the B light source 202 are selected according to the display timing of the sub-image. Multi-primary color display can be realized by switching the emission.

  In addition, if the four primary color display is realized by the conventional method, light from four types of light sources having different emission wavelengths has to be mixed, and there is a problem in that luminance unevenness and color unevenness occur. In the present embodiment, there are two types of emission wavelengths of the light source, and it is only necessary to mix the light from the two types of light sources, and the light sources can be arranged densely, thereby reducing luminance unevenness and color unevenness. It becomes possible.

(Embodiment 3)
Hereinafter, a display device according to Embodiment 3 of the present invention will be described in detail with reference to FIGS. 9 and 10. In addition, the same code | symbol is attached | subjected to the part same as Embodiment 1 of the said invention, and the description is abbreviate | omitted.

  FIG. 9 is an explanatory view schematically showing a side cross section of the third embodiment of the present invention. The display device of the present embodiment includes a first UV light source 301 (second light source) having a wavelength of emitted light of around 400 nm and a second UV light source 302 (first light source) having a wavelength of emitted light of around 365 nm. The light emitted from the first UV light source 101 and the second UV light source 102 is applied to the phosphor film 303 provided on the surface (each light source side) of the diffusion plate 103.

  The phosphor film 303 is excited by light emitted from the first UV light source 301 (hereinafter referred to as UV1 light) and converted into red light (hereinafter referred to as R light) (second wavelength conversion means); Excited by a phosphor (third wavelength converting means) that converts UV1 light into first green light (hereinafter referred to as G1 light) and light emitted from the second UV light source 302 (hereinafter referred to as UV2 light), A phosphor (first wavelength conversion means) that converts two green light (hereinafter referred to as G2 light) and a phosphor (fourth wavelength conversion means) that converts UV2 light into blue light (hereinafter referred to as B light) And have.

  A liquid crystal panel 105 is disposed on the side of the diffusion plate 103 opposite to each light source. The liquid crystal panel in this embodiment can use the same liquid crystal panel 105 as used in the first embodiment, and transmits a magenta filter that transmits B light and R light, and transmits G1 light and G2 light. And two types of pixels each having a green filter.

  Here, when the first UV light source 301 is in the light emission state and the second UV light source 302 is in the non-light emission state, the UV1 light is irradiated onto the phosphor film 303, and the UV1 light is converted into R light and G1 light by the excited phosphor. And converted to Therefore, the light applied to the liquid crystal panel 105 is a mixed light of R light and G1 light.

  On the other hand, when the first UV light source 301 is in a non-light emitting state and the second UV light source 302 is in a light emitting state, the UV2 light is irradiated onto the phosphor 303, and the excited phosphor causes the UV2 light to be converted into G2 light and B light. Converted. Therefore, the light applied to the liquid crystal panel 105 is a mixed light of G2 light and B light.

  In this manner, by providing the two types of light sources 301 and 302 and the phosphor film 303, the liquid crystal panel 105 can be irradiated with light of four types of wavelengths in the visible region. That is, by irradiating the phosphor film 303 uniformly with light from the two types of light sources of the first UV light source 301 and the second UV light source 302, it is possible to obtain illumination light of four primary colors with reduced luminance unevenness and color unevenness. Can do.

  Next, the light emission timing of each light source 302, 302 in this embodiment will be described. Also in this embodiment, a case where an image of 60 frames is displayed per second will be described, and one frame is divided into two subframes to display an image. That is, as shown in FIG. 8, one subframe period is 1/120 second, the first subframe is from 0 second to 1/120 second, and the second subframe is from 1/120 to 2/120 second. This period is repeated.

  In the first subframe, each pixel of the liquid crystal panel 105 displays a sub image corresponding to the R light and the G1 light. That is, the sub-pixel having a magenta filter performs image display corresponding to R light, and the sub-pixel having a green filter performs image display corresponding to G1 light. The light emission state of the light source at this time is such that the first UV light source 301 is in the light emission state and the second UV light source 302 is in the non-light emission state. That is, the liquid crystal panel 105 is irradiated with mixed light of R light and G1 light. Therefore, in the first subframe, images corresponding to R and G1 are displayed.

  In the second subframe, each pixel of the liquid crystal panel 105 displays a subimage corresponding to the G2 light and the B light. That is, the sub-pixel having a magenta filter performs image display corresponding to B light, and the sub-pixel having a green filter performs image display corresponding to G2 light. The light emission state of the light source at this time is such that the first UV light source 301 is in a non-light emission state and the second UV light source 302 is in a light emission state. That is, the liquid crystal panel 105 is irradiated with mixed light of G2 light and B light. Therefore, in the second subframe, images corresponding to G2 and B are displayed.

  As described above, the display colors in the first subframe and the second subframe are temporally mixed to display four primary colors. That is, the liquid crystal panel 105 is driven and controlled so that one image is formed from two sub-images having different primary colors, and two types of light emission of the first UV light source 301 and the second UV light source 302 are performed according to the display timing of the sub-image. / Multi-primary color display can be realized by switching control of non-light emission.

  In addition, if the four primary color display is realized by the conventional method, light from four types of light sources having different emission wavelengths has to be mixed, and there is a problem in that luminance unevenness and color unevenness occur. In the present embodiment, there are two types of emission wavelengths of the light source, and it is only necessary to mix the light from the two types of light sources, and the light sources can be arranged densely, thereby reducing luminance unevenness and color unevenness. It becomes possible.

(Embodiment 4)
Hereinafter, a display device according to Embodiment 4 of the present invention will be described in detail with reference to FIGS. 11 and 12. In addition, the same code | symbol is attached | subjected to the part same as Embodiment 1 of the said invention, and the description is abbreviate | omitted.

  FIG. 11 is an explanatory view schematically showing a side cross section of Embodiment 4 of the present invention, and FIG. 12 is an explanatory view schematically showing a plane of Embodiment 4 of the present invention. The display device of this embodiment includes a light guide plate 401, and a light source B (first light source) and a G light source 102, which are the same light sources as those of the first embodiment, are provided on one end face of the light guide plate 401. (Second light source) are alternately arranged. Light from each of the light sources 101 and 102 is incident on the light guide plate 401, propagates in the light guide plate 401 while being totally reflected, and is scattered by scattering dots provided on the light guide plate 401, thereby causing light from the light guide plate 401. Emitted.

  Moreover, the light utilization efficiency can be improved by disposing a reflection sheet 402 such as white PET (Poly Ethylene Terephthalate) on the surface of the light guide plate 401 opposite to the surface on which the liquid crystal panel 105 is disposed. Further, a phosphor sheet 403 is disposed between the light guide plate 401 and the liquid crystal panel 105. The phosphor sheet 403 includes a phosphor (first wavelength conversion means) that converts light emitted from the B light source 101 (hereinafter referred to as B light) into light in the green wavelength region (hereinafter referred to as G2 light), and a G light source. A phosphor (second wavelength conversion means) that converts light emitted from the light 102 (hereinafter referred to as G1 light) into light in the red wavelength region (hereinafter referred to as R light).

  Therefore, the light from the B light source 101 or the G light source 102 emitted from the light guide plate 401 is applied to the phosphor sheet 403, and R light and G2 light are emitted by the phosphor contained in the phosphor sheet 403, and the liquid crystal The panel 105 is irradiated with each of mixed light of B light and G2 light and mixed light of G1 light and R light. The liquid crystal panel 105 can be the same as that of the first embodiment, and includes a sub-pixel having a magenta filter that transmits B light and R light, and a green filter that transmits G1 light and G2 light. It is comprised by the sub pixel which has.

  With the above configuration, by controlling the liquid crystal panel 105, the B light source 101, and the G light source 102 at the timings described in the first embodiment, it is possible to display four primary colors with reduced brightness unevenness and color unevenness. In the present embodiment, the phosphor sheet 403 is disposed between the light guide plate 401 and the liquid crystal panel 105. However, the phosphor sheet 403 may be disposed between an optical sheet (not shown) such as a diffusion sheet or a prism sheet. It may be integrated with or with a phosphor applied. Further, even if the phosphor sheet 403 is disposed between the light guide plate 401 and the reflection sheet 402, or a phosphor film is formed on the surface of the reflection sheet 402, the same effect can be obtained.

(Embodiment 5)
Hereinafter, a display device according to Embodiment 5 of the present invention will be described in detail with reference to FIGS. 13 and 14. In addition, the same code | symbol is attached | subjected to the part same as Embodiment 1 of the said invention, and the description is abbreviate | omitted.

  FIG. 13 is an explanatory view schematically showing a side cross section of Embodiment 5 of the present invention, and FIG. 14 is an explanatory view schematically showing a plane of Embodiment 5 of the present invention. As shown in FIG. 13, in the display device of this embodiment, a B light source 101 (first light source) and a G light source 102 (second light source), which are the same light sources as those in the first embodiment, are liquid crystal panels (not shown). Z)). In addition, a first phosphor film 501 is disposed at a portion facing the B light source 101, and a second phosphor film 502 is disposed at a portion facing the G light source 102.

  The first phosphor film 501 has a phosphor (first wavelength conversion means) that converts light emitted from the B light source 102 (hereinafter referred to as B light) into light in the green wavelength region (hereinafter referred to as G2 light). is doing. The second phosphor film 502 has a phosphor (second wavelength conversion means) that converts light emitted from the G light source 102 (hereinafter referred to as G1 light) into light in the red wavelength region (hereinafter referred to as R light). is doing. Here, the first phosphor film 501 and the second phosphor film 502 can be manufactured on the same member. For example, two kinds of phosphors are separately applied to one translucent sheet. Can be realized.

  When the light sources are two-dimensionally arranged, the B light source 101 and the G light source 102 are arranged alternately as shown in FIG. 14A, and as shown in FIG. 14B. By arranging the first phosphor film 501 and the second phosphor film 502 in a checkered pattern according to the arrangement of the light sources 101 and 102, luminance unevenness and color unevenness can be reduced.

  Here, when the B light source 101 is in a light emitting state, a mixed light of the B light emitted from the B light source 101 and the G2 light converted by the phosphor in the first phosphor film 501 is obtained, and the G light source When 102 is in a light emitting state, mixed light of G1 light emitted from the G light source 102 and R light converted by the phosphor in the second phosphor film 502 is obtained.

  That is, by arranging the phosphor film corresponding to the vicinity of the light source, the B light does not pass through the second phosphor film 502 that emits R light, and the G1 light does not pass through the first phosphor film 501 that emits G2 light. Therefore, scattering and absorption of light can be reduced, and light utilization efficiency can be improved. Therefore, by applying the light source and the phosphor film shown in the present embodiment instead of the phosphor film and the phosphor sheet shown in each of the embodiments described above, multi-primary color display with reduced luminance unevenness and color unevenness can be efficiently performed. It can be realized well.

  In each of the above-described embodiments, one frame period is divided into first and second subframe periods, and lighting / non-lighting of the first and second light sources is selectively switched in each period. However, a subframe period in which display luminance is improved by turning on all the light sources may be provided.

  Any device that displays multi-primary color images using illumination light from a light source is applicable, and is applicable not only to familiar devices such as personal computers and television receivers, but also to measuring devices, medical devices, and general industrial devices. It is.

It is a sectional side view which shows schematic structure in Embodiment 1 of this invention. It is explanatory drawing which shows the pixel structure of the liquid crystal panel (light modulation means) in Embodiment 1 of this invention. It is explanatory drawing which shows the emission wavelength spectrum of each state in Embodiment 1 of this invention. It is explanatory drawing which shows the wavelength spectrum of the irradiation light in Embodiment 1 of this invention, and the permeation | transmission characteristic of a color filter. It is explanatory drawing which shows the display control of the liquid crystal panel and the light emission timing of a light source in Embodiment 1 of this invention. It is a block diagram which shows the schematic system configuration | structure in Embodiment 1 of this invention. It is a sectional side view which shows schematic structure in Embodiment 2 of this invention. It is explanatory drawing which shows the display control of the liquid crystal panel in Embodiment 2 of this invention, and the light emission timing of a light source. It is a sectional side view which shows schematic structure in Embodiment 3 of this invention. It is explanatory drawing which shows the display control of the liquid crystal panel in Embodiment 3 of this invention, and the light emission timing of a light source. It is a sectional side view which shows schematic structure in Embodiment 4 of this invention. It is a top view which shows schematic structure in Embodiment 4 of this invention. It is a sectional side view which shows schematic structure in Embodiment 5 of this invention. It is a top view which shows schematic structure in Embodiment 5 of this invention.

Explanation of symbols

101 B light source 102 G light source 103 Diffuser plate 104 Phosphor film 105 Liquid crystal panel 111 Image conversion circuit 112 Buffer 113 Buffer 114 Timing control circuit 115 Liquid crystal drive circuit 116 LED drive circuit 201 UV light source 202 B light source 203 Phosphor film 301 First UV light source 302 Second UV light source 303 Phosphor film 401 Light guide plate 402 Reflective sheet 403 Phosphor sheet 501 First phosphor film 502 Second phosphor film

Claims (19)

A first light source and a second light source having different emission wavelength ranges;
First wavelength conversion means for converting the wavelength of at least part of the light from the first light source;
Second wavelength conversion means for converting the wavelength of at least part of the light from the second light source;
In a display device comprising a light modulation means for modulating light intensity according to a video signal,
The light modulating means is controlled to form one image from a plurality of sub-images;
A display device, wherein the light emission of the first light source and the second light source is switched corresponding to the sub-image. The display device according to claim 1,
The light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated,
The first pixel modulates the light intensity in the emission wavelength region of the first light source and the light intensity in the emission wavelength region of the second light source,
The display device, wherein the second pixel modulates the light intensity in the wavelength region converted by the first wavelength conversion unit and the light intensity in the wavelength region converted by the second wavelength conversion unit. The liquid crystal display device according to claim 1,
The light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated,
The first pixel modulates the light intensity of the light emission wavelength region of the first light source and the light intensity of the wavelength region converted by the second wavelength conversion unit,
The display device characterized in that the second pixel modulates the light intensity in the wavelength region converted by the first wavelength conversion means and the light intensity in the light emission wavelength region of the second light source.   4. The display device according to claim 3, wherein wavelength regions of light modulated by the first pixel are a blue wavelength region and a red wavelength region. The liquid crystal display device according to claim 1,
A display device comprising: third wavelength conversion means for converting the wavelength of at least part of light from the second light source into a wavelength region different from the wavelength region converted by the second wavelength conversion means. The display device according to claim 5,
The light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated,
The first pixel modulates the light intensity in the emission wavelength region of the first light source and the light intensity in the wavelength region converted by the third wavelength conversion unit,
The display device, wherein the second pixel modulates the light intensity in the wavelength region converted by the first wavelength conversion unit and the light intensity in the wavelength region converted by the second wavelength conversion unit. The display device according to claim 5,
The light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated,
The first pixel modulates the light intensity of the light emission wavelength region of the first light source and the light intensity of the wavelength region converted by the second wavelength conversion unit,
The display device characterized in that the second pixel modulates the light intensity in the wavelength region converted by the first wavelength conversion means and the light intensity in the wavelength region converted by the third wavelength conversion means.   8. The display device according to claim 7, wherein wavelength regions of light modulated by the first pixel are a blue wavelength region and a red wavelength region. The display device according to claim 5,
A display device comprising: fourth wavelength conversion means for converting the wavelength of at least part of light from the first light source into a wavelength region different from the wavelength region converted by the first wavelength conversion means. The display device according to claim 9,
The light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated,
The first pixel modulates the light intensity of the wavelength region converted by the fourth wavelength conversion unit and the light intensity of the wavelength region converted by the third wavelength conversion unit,
The display device, wherein the second pixel modulates the light intensity in the wavelength region converted by the first wavelength conversion unit and the light intensity in the wavelength region converted by the second wavelength conversion unit. The display device according to claim 9,
The light modulation means includes a first pixel and a second pixel having different wavelength regions of light to be modulated,
The first pixel modulates the light intensity of the wavelength region converted by the fourth wavelength conversion unit and the light intensity of the wavelength region converted by the second wavelength conversion unit,
The display device, wherein the second pixel modulates the light intensity in the wavelength region converted by the first wavelength conversion unit and the light intensity in the wavelength region converted by the third wavelength conversion unit.   12. The display device according to claim 11, wherein wavelength regions of light modulated by the first pixel are a blue wavelength region and a red wavelength region.   The display device according to any one of claims 1 to 12, wherein the first light source or the second light source is a light emitting diode.   14. The display device according to claim 1, wherein an emission wavelength region of the first light source is a blue wavelength region.   The display device according to claim 5, wherein an emission wavelength region of the second light source is an ultraviolet wavelength region.   The display device according to claim 9, wherein an emission wavelength region of the first light source is an ultraviolet wavelength region.   17. The device according to claim 1, wherein the first wavelength conversion unit and / or the second wavelength conversion unit and / or the third wavelength conversion unit and / or the fourth wavelength conversion unit is a phosphor. The display apparatus in any one.   The display device according to claim 1, wherein the wavelength region converted by the second wavelength conversion unit is a red wavelength region. The display device according to claim 1, wherein the light modulation unit is a liquid crystal panel.

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