JP2013104888A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of clear display regardless of the surrounding brightness.SOLUTION: A display device 1 of the present invention includes a backlight 2 (light source), a liquid crystal optical modulation element 3, a phosphor layer 13 (wavelength conversion unit), and a color filter 25 provided for the wavelength conversion unit on a visible side. The liquid crystal optical modulation element includes a liquid crystal layer, a first substrate, a second substrate, a first polarizer, a second polarizer, and a reflection film 12 reflecting light which enters from the visible side through the color filter and the liquid crystal layer. A unit region of the liquid crystal optical modulation element includes a reflection region R as a region where the reflection film is formed and a transmission region T as a region where the reflection film is not formed.

Description

  The present invention relates to a display device.

  2. Description of the Related Art Conventionally, there has been provided a liquid crystal display device that performs display using external light in a bright place, while performing display using light from a built-in backlight in a dark place. That is, this type of liquid crystal display device has a display method that has both a reflection mode and a transmission mode, and switches to either the reflection mode or the transmission mode depending on the brightness of the environment. As a result, it is possible to display clearly regardless of the brightness of the environment while reducing power consumption. Hereinafter, in this specification, this type of liquid crystal display device is referred to as a “semi-transmissive liquid crystal display device”.

  A transflective color liquid crystal display device including a color filter has been proposed (see, for example, Patent Document 1). In this liquid crystal display device, a color filter is disposed on the inner surface of the opposite glass substrate. In this color filter, a fluorescent pigment or a fluorescent dye that excites light in the complementary color region and converts it into light in a predetermined wavelength region is included in both the reflected light passing portion and the transmitted light passing portion.

  A reflective liquid crystal display device having a color conversion layer made of a phosphor has been proposed (see, for example, Patent Document 2). In this liquid crystal display device, in a dark environment, an auxiliary light source disposed behind the liquid crystal cell (second substrate) is turned on, and light from the auxiliary light source is used for display. At this time, the color conversion layer on the second substrate converts the blue light from the auxiliary light source into red, green, and blue color light, and the converted light is reflected by the first reflector on the first substrate. Let Further, the reflected light is reflected by the second reflecting plate on the second substrate through the liquid crystal layer and the color filter, and taken out from the first substrate side.

JP 2003-167243 A JP 2001-133770 A

  In the liquid crystal display device described in Patent Document 1, a color filter containing a fluorescent pigment or a fluorescent dye is disposed on the inner surface of the opposing glass substrate, that is, the viewing-side glass substrate. Therefore, external light such as sunlight or illumination light is applied to the color filter via the glass substrate on the viewing side. At this time, the fluorescent pigment and fluorescent dye contained in the color filter are excited by external light. As a result, unintended unnecessary light is emitted, resulting in a reduction in display contrast ratio. Further, white light emitted from the backlight excites the fluorescent pigment or fluorescent dye, but light in the long wavelength region of white light does not contribute to excitation. For this reason, there is a problem that the utilization efficiency of light from the backlight is low.

  In the liquid crystal display device described in Patent Document 2, the light from the auxiliary light source is collected in the color conversion layer, the light emitted from the color conversion layer is transmitted through the opening of the second reflecting plate, and the position corresponding to the opening Need to be collected on the first reflector. However, since the light from the phosphor of the color conversion layer is emitted isotropically, only part of the light emitted from the phosphor reaches the first reflector. Therefore, there is a problem that the utilization efficiency of light from the auxiliary light source is low.

  The present invention has been made to solve the above-described problem, and can suppress the excitation of a phosphor due to the incidence of external light as much as possible, and can provide a clear display regardless of the brightness of the environment. The purpose is to provide. It is another object of the present invention to provide a display device with excellent light utilization efficiency.

  In order to achieve the above object, a display device of the present invention includes a light source that emits first light, a liquid crystal light modulation element that controls a transmission amount of the first light incident from the light source, and the liquid crystal Provided at least in part on the viewing side of the light modulation element, and is excited by the first light incident from the liquid crystal light modulation element to emit second light having a wavelength band different from the wavelength band of the first light. A wavelength conversion unit including a phosphor, provided on the viewing side of the liquid crystal light modulation element and the wavelength conversion unit, transmits light in the wavelength band of the second light, and other than the wavelength band of the second light A color filter that absorbs light in a wavelength band, wherein the liquid crystal light modulation element is a liquid crystal layer, a first substrate disposed on the light source side of the liquid crystal layer, and the color filter side of the liquid crystal layer A second substrate disposed in front of the liquid crystal layer Reflects light incident from the viewing side through the first polarizing plate disposed on the light source side, the second polarizing plate disposed on the color filter side of the liquid crystal layer, and the color filter and the liquid crystal layer. The liquid crystal light modulation element includes a plurality of unit regions, and each of the plurality of unit regions is a reflection region that is a formation region of the reflection film and a non-formation region of the reflection film. And a transmission region that transmits the first light toward the wavelength conversion unit.

  The display device of the present invention is characterized in that the wavelength conversion unit and the reflective film overlap at least partially when viewed from the normal direction of the first substrate and the second substrate.

  In the display device of the present invention, a retardation plate is provided on an optical path between the color filter and the reflective film in the reflection region, and the retardation plate and the second polarizing plate transmit incident light. A circularly polarizing plate that converts circularly polarized light is configured, and the retardation plate and the reflective film overlap at least partially when viewed from the normal direction of the first substrate and the second substrate. .

  The display device of the present invention is characterized in that at least a part of the reflection region has a region where the wavelength conversion unit is not provided.

  The display device according to the present invention is characterized in that the plurality of unit areas include a plurality of unit areas arranged adjacent to each other and displaying different colors.

  In the display device of the present invention, the reflection region is provided in a direction along a boundary with a unit region that displays different colors among a plurality of boundaries between a unit region to which the reflection region belongs and an adjacent unit region. It is characterized by.

  In the display device according to the aspect of the invention, the unit area is a rectangle, and the reflection area includes two sides corresponding to a boundary with a unit area that displays different colors among the four sides of the unit area to which the reflection area belongs. The transmission region is provided in a central portion of the unit region and surrounded by the reflection region provided along the two or more sides. Features.

  In the display device according to the aspect of the invention, when the transmission amount of the first light in the liquid crystal light modulation element is maximum or minimum, the phase difference of the liquid crystal layer in the substrate normal direction in the transmission region is displayed in different colors. The wavelength of the first light is approximately ½ regardless of the unit region for performing the above.

  In the display device according to the aspect of the invention, when the transmission amount of the first light in the liquid crystal light modulation element is maximum or minimum, the phase difference of the liquid crystal layer in the substrate normal direction in the reflection region is displayed in different colors. It is characterized in that it is approximately ¼ of the wavelength of the display color for each unit region for performing the above.

  In the display device of the present invention, a first retardation plate is provided on the optical path between the liquid crystal layer and the first polarizing plate, and the optical path between the liquid crystal layer and the second polarizing plate is provided. A second retardation plate is provided, and in the transmission region, the phase difference of the first retardation plate is approximately equal to the wavelength of the first light regardless of the unit region for displaying different colors. In the transmission region, the phase difference of the second retardation plate is approximately ¼ of the wavelength of the first light regardless of the unit region for displaying different colors. It is characterized by that.

  In the display device of the present invention, a second retardation plate is provided on the optical path between the liquid crystal layer and the second polarizing plate, and the retardation of the second retardation plate is in the reflection region. The unit region for displaying different colors is approximately ¼ of the wavelength of the display color.

  In the display device of the present invention, the first polarizing plate has polarization characteristics corresponding to the wavelength band of the first light, and the second polarizing plate is polarized light corresponding to the entire wavelength band of visible light. It has the characteristics.

  The display device of the present invention includes a light collecting member that condenses the first light emitted from the light source in the transmission region of the liquid crystal light modulation element.

  The display device of the present invention transmits light in the wavelength band of the first light on the optical path between the second polarizing plate and the wavelength conversion unit, and has a wavelength other than the wavelength band of the first light. A wavelength selective transmission layer that reflects light in the wavelength band is provided.

  The display device of the present invention includes a reflective polarizing plate having a polarization characteristic corresponding to a wavelength band of the first light on an optical path between the light source and the liquid crystal light modulation element.

  According to the present invention, it is possible to suppress the excitation of the phosphor due to the incidence of external light as much as possible, and to realize a display device capable of clear display regardless of the brightness of the environment. In addition, a display device with excellent light utilization efficiency can be realized.

It is sectional drawing which shows the display apparatus of 1st Embodiment of this invention. In the display apparatus of 1st Embodiment, it is a figure which shows sectional drawing and a top view of one dot. It is a figure which shows the display principle of the display apparatus of 1st Embodiment, Comprising: (A) shows the display principle of transmission mode, (B) shows the display principle of reflection mode, respectively. It is sectional drawing which shows the 1st modification of the display apparatus of 1st Embodiment. It is a top view of one dot in the 2nd modification of a display of a 1st embodiment. It is sectional drawing which shows the 3rd modification of the display apparatus of 1st Embodiment. It is sectional drawing which shows the 4th modification of the display apparatus of 1st Embodiment. It is sectional drawing which shows the 5th modification of the display apparatus of 1st Embodiment. It is a figure which shows the top view of one dot in the display apparatus of 2nd Embodiment of this invention. It is a figure for demonstrating the effect of the display apparatus of 2nd Embodiment, (A) is the effect | action of the light in the display apparatus of this embodiment, (B) is the effect | action of the light in the display apparatus of 1st Embodiment. Each is shown. It is a top view of one dot which shows the 1st modification of a display of a 2nd embodiment. It is a top view of one dot which shows the 2nd modification of a display of a 2nd embodiment. It is sectional drawing which shows the display apparatus of 3rd Embodiment of this invention. It is sectional drawing which shows the display apparatus of 4th Embodiment of this invention. It is sectional drawing which shows the display apparatus of 5th Embodiment of this invention. It is sectional drawing which shows the display apparatus of 6th Embodiment of this invention. It is sectional drawing which shows the display apparatus of 7th Embodiment of this invention.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The display device of this embodiment is a transflective display device that has both a reflection mode and a transmission mode. The reflection mode of the conventional transflective liquid crystal display device and the transmission mode of the fluorescence excitation color conversion display method , And a display device.

FIG. 1 is a cross-sectional view showing the display device of this embodiment. FIG. 2 is a diagram showing a cross-sectional view and a plan view of one pixel in the display device of this embodiment. 3A and 3B are diagrams showing the display principle of the display device of the present embodiment, where FIG. 3A shows the display principle of the transmission mode, and FIG. 3B shows the display principle of the reflection mode.
In the following drawings, in order to make each component easy to see, the scale of dimensions may be different depending on the component.

As shown in FIG. 1, the display device 1 according to the present embodiment includes a backlight 2, a liquid crystal light modulation element 3, and a phosphor substrate 4. The liquid crystal light modulation element 3 includes a liquid crystal cell 5, a first polarizing plate 6 disposed on the backlight 2 side of the liquid crystal cell 5, and a second polarizing plate disposed on the phosphor substrate 4 side of the liquid crystal cell 5. 7. The liquid crystal cell 5 includes a liquid crystal layer 8 and a pair of substrates 9 and 10 that sandwich the liquid crystal layer 8.
Hereinafter, of the pair of substrates 9 and 10, the substrate 9 disposed on the backlight 2 side of the liquid crystal layer 8 is referred to as a “first substrate”, and the substrate 10 disposed on the phosphor substrate 4 side of the liquid crystal layer 8. Is referred to as a “second substrate”.

On the first substrate 9, a reflective film 12 that reflects light incident from the viewing side through the phosphor substrate 4 and the liquid crystal layer 8 is provided. In the reflection mode, the display device 1 performs display using external light such as sunlight and illumination light incident from the outside of the phosphor substrate 4 (upper side in FIG. 1). In the transmission mode, the display device 1 performs display using light from the backlight 2 incident from the outside of the first substrate 9 (downward in FIG. 1). At this time, in the transmission mode, display is performed using red light and green light generated by wavelength conversion of the blue light emitted from the backlight 2 by the phosphor.
Therefore, the observer visually recognizes the display from the outside of the phosphor substrate 4 (upper side in FIG. 1). In the following description, the upper side of the sectional view of FIG. 1 or the like may be referred to as the viewing side or the near side, and the lower side of the sectional view may be referred to as the back side.

  The display device 1 is provided so that three dots (a plurality of unit regions) for displaying different colors are adjacent to each other. The three dots are a red dot DR for displaying with red light, a green dot DG for displaying with green light, and a blue dot DB for displaying with blue light. One pixel, which is the minimum unit constituting the display, is composed of these three dots: red dot DR, green dot DG, and blue dot DB. The “dot” in the present embodiment corresponds to a “unit area” in the claims.

  The backlight 2 of the present embodiment emits blue light having a wavelength band of 430 to 480 nm, for example. Although a detailed description of the configuration of the backlight 2 is omitted, the backlight 2 emits, for example, a light emitting diode (hereinafter abbreviated as LED) that emits blue light, and light emitted from the LED in a planar shape. A light guide plate. In addition, the backlight 2 may include, for example, a prism sheet for raising the traveling direction of light emitted from the light guide plate in the normal direction of the light guide plate. The “backlight” in the present embodiment corresponds to the “light source” in the claims. “Blue light” in the present embodiment corresponds to “first light” in the claims.

  As the backlight 2, it is desirable to use a backlight having high directivity as the light emission direction so that light is incident in a direction as perpendicular as possible to the substrate surface of the liquid crystal cell 5. The reason is that if the directivity of the backlight is low and the ratio of light that is obliquely transmitted through the liquid crystal layer is large, the light that is obliquely transmitted through the liquid crystal layer causes a decrease in the contrast ratio.

Hereinafter, a detailed configuration of the liquid crystal light modulation element 3 will be described.
The upper side of FIG. 2 is a cross-sectional view showing the configuration of the red dot DR among the three dots. The lower side of FIG. 2 is a plan view of red dots DR showing the positional relationship between the reflective film 12 and the phosphor layer 13. Here, an example of the red dot DR will be described, but the configuration of the green dot DG and the blue dot DB is the same as that of the red dot DR, and thus the description thereof is omitted.

  As shown in FIGS. 1 and 2, the liquid crystal cell 5 includes a liquid crystal layer 8, and a first substrate 9 and a second substrate 10 that sandwich the liquid crystal layer 8. The first substrate 9 and the second substrate 10 are light transmissive substrates made of glass, plastic, or the like. The first substrate 9 and the second substrate 10 may be made of the same material or may be made of different materials. The display mode of the liquid crystal cell 5 is not particularly limited. For example, a horizontal electric field mode such as TN (Twisted Nematic) mode, ECB (Electrically Controlled Birefringence) mode, VA (Vertical Alignment) mode, IPS (In-Plane Switching), etc. Either of these may be adopted.

  On the inner surface (surface on the liquid crystal layer 8 side) of the first substrate 9, an insulating film 14 protruding toward the liquid crystal layer 8 is formed in a partial region. The cross-sectional shape of the insulating film 14 is trapezoidal, and the film thickness of the insulating film 14 is approximately ½ of the thickness of the liquid crystal layer 8 in the region where the insulating film 14 is not present. A reflective film 12 is formed along the upper surface and side surfaces (inclined surfaces) of the insulating film 14. The reflective film 12 is made of a highly light reflective material such as aluminum. On the inner surface of the first substrate 9, a pixel electrode 15 is provided across a region where the reflective film 12 is formed and a region where the reflective film 12 is not formed. The pixel electrode 15 is made of a transparent conductive film such as indium tin oxide (hereinafter abbreviated as ITO). On the inner surface of the first substrate 9, a first alignment film 16 that restricts the alignment state of the liquid crystal when no voltage is applied is provided so as to cover the pixel electrode 15. The first alignment film 16 is made of a resin such as polyimide, for example.

  The pixel electrode 15 is provided separately for each dot. Although not shown, a thin film transistor (hereinafter abbreviated as TFT) for controlling voltage writing to the pixel electrode 15 is provided on the inner surface of the first substrate 9. And the TFT are electrically connected. With this configuration, a voltage for driving the liquid crystal layer 8 can be individually applied to the pixel electrode 15 of each dot. In addition to the TFT, the first substrate 9 is provided with a plurality of data lines and a plurality of scanning lines (not shown). The liquid crystal cell 5 of the present embodiment is an active matrix type liquid crystal cell including a TFT as a driving element for each pixel.

  On the inner surface (surface on the liquid crystal layer side) of the second substrate 10, a counter electrode 19 and a second alignment film 20 are sequentially stacked via a second retardation plate 18 described later. Similar to the pixel electrode 15, the counter electrode 19 is made of a transparent conductive film such as ITO. Unlike the pixel electrode 15, the counter electrode 19 is not separated for each dot, but is provided in common over a plurality of dots. Therefore, a common potential is applied to the counter electrode 19 over a plurality of dots. Similar to the first alignment film 16, the second alignment film 20 is made of a resin such as polyimide.

  Of one dot, a region where the reflective film 12 is formed is referred to as a “reflective region”, and a region where the reflective film 12 is not formed, that is, a region where the reflective film is opened is referred to as a “transmissive region”. That is, the liquid crystal cell 5 of the present embodiment includes two regions of the reflective region R and the transmissive region T in one dot. In the reflective region R, external light incident from the viewing side is reflected by the reflective film 12, and the liquid crystal layer 8 controls the transmittance of the reflected light for display. In the transmissive region T, the light incident from the backlight 2 is transmitted through the opening of the reflective film 12 toward the phosphor layer 13 of the phosphor substrate 4 described later, and the transmittance of the transmitted light is transmitted by the liquid crystal layer 8. Control the display.

  When the reflection region R and the transmission region T are compared, the insulating film 14 is selectively formed only in the reflection region R, so that the thickness of the liquid crystal layer 8 in the reflection region R (reflection cell thickness dR) and the transmission region T are compared. The thickness of the liquid crystal layer 8 (transmission cell thickness dT) is different. That is, the thickness of the liquid crystal layer 8 in the reflection region R (reflection cell thickness dR) is approximately ½ of the thickness of the liquid crystal layer 8 in the transmission region T (transmission cell thickness dT).

  In the transmissive region T, when the transmittance of the blue light from the backlight 2 is maximum or minimum, the phase difference due to the thickness of the liquid crystal layer 8 has the wavelength of the blue light regardless of the dots displaying different colors. It is about 1/2. That is, when blue light having a peak wavelength indicating the maximum intensity of 450 nm is used as a backlight, the phase difference due to the thickness of the liquid crystal layer 8 in the transmission region T is substantially over all of the red dots DR, green dots DG, and blue dots DB. 225 nm.

  In the reflection region R, when the transmittance of the blue light from the backlight 2 is maximum or minimum, the phase difference of the liquid crystal layer 8 in the normal direction of the substrate is different from the wavelength of the display color for each dot displaying different colors. Is about 1/4 of that. That is, when the peak wavelength of green light is 550 nm and the peak wavelength of red light is 630 nm, the phase difference of the liquid crystal layer 8 in the substrate normal direction in the reflection region R of the red dot DR is approximately 158 nm. The phase difference of the liquid crystal layer 8 in the normal direction of the substrate in the reflection region R of the green dot DG is approximately 138 nm. The phase difference of the liquid crystal layer 8 in the normal direction of the substrate in the reflection region R of the blue dot DB is approximately 113 nm.

  Specifically, the phase difference of the liquid crystal layer 8 in the normal direction of the substrate is represented by the product of the refractive index of the liquid crystal layer 8 and the thickness of the liquid crystal layer 8 (transmission cell thickness dT or reflection cell thickness dR). Therefore, when setting the phase difference of the liquid crystal layer 8 in the substrate normal direction in each region of each dot as described above, if the liquid crystal material to be used is determined, the refractive index of the liquid crystal layer is determined. The thickness of the liquid crystal layer 8 in the transmission region T (transmission cell thickness dT) and the thickness of the insulating film 14 may be set appropriately.

  The first polarizing plate 6 absorbs the first linearly polarized light having a predetermined polarization direction and absorbs the second linearly polarized light having a polarization direction orthogonal to the polarization direction of the first linearly polarized light. Type polarizing plate. Similarly, the second polarizing plate 7 transmits the first linearly polarized light having a predetermined polarization direction and absorbs the second linearly polarized light having a polarization direction orthogonal to the polarization direction of the first linearly polarized light. It is the absorption-type polarizing plate which has. The first polarizing plate 6 and the second polarizing plate 7 are disposed so that the transmission axes are orthogonal to each other.

It is desirable that the first polarizing plate 6 has a polarization characteristic corresponding to the wavelength band of blue light. As an example of a specific configuration of the first polarizing plate 6, a polarizing plate including an iodine complex such as I ₃ ⁻ and I ₅ ⁻ in a resin base material can be given. However, iodine Motohen light plate that is generally used conventionally I ₃ ^-, I ₅ ^- contains iodine complexes such. The difference between the first polarizing plate 6 of the present embodiment and the conventional polarizing plate is the component ratio of the iodine complex. That is, in the first polarizing plate 6 of the present embodiment, the proportion of the I ₃ ⁻ iodine complex in the entire iodine complex is larger than that of the conventional iodine polarizing plate. Examples of the resin base material include polyvinyl alcohol that is generally used for polarizing plates for liquid crystal displays.

I ₃ ^- The content of iodine complex of affecting the orthogonal absorbance at a wavelength of 480 nm, I ₅ ^- the content of iodine complex is known to influence the orthogonality absorbance at a wavelength of 610 nm. I ₃ ^- of Increasing than the conventional content of iodine complex, the light absorption in the short wavelength region (blue region) can be increased than before. In other words, I ₃ ^- in by increasing than the conventional content of iodine complex, it is possible to shift the peak of the absorbance curve than conventional short wavelength side (blue region side).

It is desirable that the second polarizing plate 7 has a polarization characteristic corresponding to the entire wavelength band of visible light. Therefore, as an example of a specific configuration of the second polarizing plate 7, a polarizing plate including an iodine complex such as the aforementioned I ₃ ⁻ and I ₅ ⁻ in a resin base material can be given. In addition, a conventional general polarizing plate can be used.

  A first retardation plate 22 is provided between the first substrate 9 and the first polarizing plate 6. A second phase difference plate 18 is provided between the second substrate 10 and the counter electrode 19. That is, in the case of this embodiment, the first retardation plate 22 is a retardation plate disposed outside the liquid crystal cell 5, a so-called out-cell type retardation plate. The second retardation plate 18 is a retardation plate built in the liquid crystal cell 5, a so-called in-cell type retardation plate. The first retardation plate 22 and the second retardation plate 18 are preferably used as a pair of retardation plates, and it is not preferable to use only one retardation plate. Further, both the first retardation plate 22 and the second retardation plate 18 may be omitted.

  The phase difference of the first retardation plate 22 is approximately ¼ of the wavelength of blue light regardless of the dots that display different colors. That is, when blue light having a peak wavelength indicating the maximum intensity of 450 nm is used as the backlight, the phase difference of the first retardation plate 22 is approximately 113 nm over all of the red dots DR, green dots DG, and blue dots DB. .

  The axial direction of the first retardation plate 22 is arranged so as to form an angle of about 45 degrees with respect to the absorption axis of the first polarizing plate 6. Since the phase difference of the first retardation plate 22 is approximately ¼ of the wavelength of blue light, the first polarizing plate 6 and the first retardation plate 22 function as a circularly polarizing plate. Therefore, the blue light from the backlight 2 is converted into circularly polarized light by passing through the first polarizing plate 6 and the first retardation plate 22 and enters the liquid crystal layer 8.

  The phase difference of the second retardation plate 18 is approximately ¼ of the wavelength of the blue light in the transmission region T regardless of the dots that display different colors. That is, when blue light having a peak wavelength of 450 nm indicating the maximum intensity is used as a backlight, the phase difference of the second retardation plate 18 in the transmission region T over all of the red dots DR, green dots DG, and blue dots DB. Is approximately 113 nm.

  In the reflection region R, the phase difference of the second retardation plate 18 is approximately ¼ of the wavelength of the display color for each dot that displays a different color. That is, when the peak wavelength of green light is 550 nm and the peak wavelength of red light is 630 nm, the phase difference of the second retardation plate 18 in the reflection region R of the red dot DR is approximately 158 nm. The phase difference of the second retardation plate 18 in the reflection region R of the green dot DG is approximately 138 nm. The phase difference of the second retardation plate 18 in the reflection region R of the blue dot DB is approximately 113 nm.

  The axial direction of the second retardation plate 18 is arranged so as to form an angle of about 45 degrees with respect to the absorption axis of the second polarizing plate 7. In the reflection region R, since the phase difference of the second retardation plate 18 is approximately ¼ of the wavelength of each display color, the second polarizing plate 7 and the second retardation plate 18 are circularly polarized. Functions as a board. Therefore, external light incident through the phosphor substrate 4 is converted into circularly polarized light by passing through the second polarizing plate 7 and the second retardation plate 18 and is incident on the liquid crystal layer 8.

As shown in FIG. 1, the phosphor substrate 4 includes a substrate 24, a color filter 25, and a phosphor layer 13. The phosphor layer 13 includes a phosphor that is excited by blue light incident from the liquid crystal light modulation element 3 and emits fluorescence in a wavelength band different from the wavelength band of blue light. That is, the “phosphor layer” of the present embodiment has a function of converting the wavelength of the blue light incident from the liquid crystal light modulation element 3 and corresponds to a “wavelength conversion unit” in the claims.
As the substrate 24, a substrate having optical transparency such as glass or plastic is used as in the substrate constituting the liquid crystal cell 5.

  In the red dot DR, as the color filter 25, a red color filter layer 25R that transmits light in the wavelength band of red light and absorbs light in a wavelength band other than the wavelength band of red light is provided. Further, as the phosphor layer 13, a red phosphor layer 13 </ b> R including a phosphor that is excited by blue light and emits fluorescence in the red wavelength band is provided.

  Similarly, in the green dot DG, as the color filter 25, a green color filter layer 25G that transmits light in the wavelength band of green light and absorbs light in a wavelength band other than the wavelength band of green light is provided. Further, as the phosphor layer 13, a green phosphor layer 13 </ b> G including a phosphor that is excited by blue light and emits fluorescence in the green wavelength band is provided.

  On the other hand, in the blue dot DB, the color filter 25 is provided with a blue color filter layer 25B that transmits light in the wavelength band of blue light and absorbs light in a wavelength band other than the wavelength band of blue light. . Further, instead of the phosphor layer 13 used for the red dots DR and the green dots DG, a scatterer layer 26 including a scatterer that scatters blue light is provided. That is, in the blue dot DB, the scatterer layer 26 is used in place of the phosphor layer 13 in order to use the blue light from the backlight 2 for display without wavelength conversion. By diffusing the blue light by the scatterer layer 26, the diffusion characteristics of the light emitted from the red phosphor layer 13R and the green phosphor layer 13G that generate isotropic light and the light emitted from the scatterer layer 26 are matched. Can be included.

  The transmission spectrum of the red color filter layer 25R is close to the emission spectrum of red light emitted from the red phosphor layer 13R excited by blue light. Similarly, the transmission spectrum of the green color filter layer 25G is close to the emission spectrum of green light emitted from the green phosphor layer 13G excited by blue light. Further, the transmission spectrum of the blue color filter layer 25B is close to the spectrum of blue light after being scattered by the scatterer layer 26. The film thicknesses of the color filter layers 25R, 25G, and 25B may be different between the transmission region T and the reflection region R for each color.

  Said fluorescent substance layer 13 may be comprised only from the fluorescent substance illustrated below, and may contain the additive etc. arbitrarily. Or the structure by which these fluorescent substance was disperse | distributed in binders, such as a resin material and an inorganic material, may be sufficient. As the phosphor of this embodiment, a known phosphor material can be used. This type of phosphor material can be classified into an organic phosphor material and an inorganic phosphor material. Although these specific compounds are illustrated below, this embodiment is not limited to these materials.

  In the organic phosphor material, a coumarin dye: 2,3,5,6-1H, 4H-tetrahydro-8-trifluoromethylquinolidine (9,9a, 1) is used as a fluorescent material that converts blue light into green light. -Gh) Coumarin (coumarin 153), 3- (2'-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), 3- (2'-benzimidazolyl) -7-N, N-diethylaminocoumarin (coumarin 7), na Phthalimide dyes: basic yellow 51, solvent yellow 11, solvent yellow 116 and the like. Further, as a fluorescent material for converting blue light into red light, cyanine dye: 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, pyridine dye: 1-ethyl- 2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] -pyridinium-perchlorate and rhodamine dyes: rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, basic violet 11, sulfo Rhodamine 101 etc. are mentioned.

In inorganic phosphor materials, (BaMg) Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺ , Sr ₄ Al ₁₄ O ₂₅ : Eu ²⁺ , (SrBa) Al are used as fluorescent materials that convert blue light into green light. ₁₂ Si ₂ O ₈ : Eu ²⁺ , (BaMg) ₂ SiO ₄ : Eu ²⁺ , Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ , Sr ₂ P ₂ O ₇ —Sr ₂ B ₂ O ₅ : Eu ^{2 +} , (BaCaMg) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , Sr ₂ Si ₃ O ₈ -2SrCl ₂ : Eu ²⁺ , Zr ₂ SiO ₄ , MgAl ₁₁ O ₁₉ : Ce ³⁺ , Tb ³⁺ , Ba ₂ SiO ₄ : Eu ²⁺ , Sr ₂ SiO ₄ : Eu ²⁺ , (BaSr) SiO ₄ : Eu ^{2+ and the} like. Further, as a fluorescent material for converting blue light into red light, Y ₂ O ₂ S: Eu ³⁺ , YAlO ₃ : Eu ³⁺ , Ca ₂ Y ₂ (SiO ₄ ) ₆ : Eu ³⁺ , LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , YVO ₄ : Eu ³⁺ , CaS: Eu ³⁺ , Gd ₂ O ₃ : Eu ³⁺ , Gd ₂ O ₂ S: Eu ³⁺ , Y (P, V) O ₄ : Eu ³⁺ , Mg ₄ GeO _5.5 F: Mn ⁴⁺ , Mg ₄ GeO ₆ : Mn ⁴⁺ , K ₅ Eu _2.5 (WO ₄ ) _6.25 , Na ₅ Eu _2.5 (WO ₄ ) _6.25 , K ₅ Eu _2.5 (MoO ₄ ) _6.25 , Na ₅ Eu _2.5 (MoO ₄ ) _{6.25, and the} like.
Furthermore, it is known that fluorescent emission is obtained by miniaturizing a semiconductor material such as CdSe, ZnSe, InP, or Si to a nano size. Visible light is emitted with a size of about 2 to 8 nm, but the smaller the particle diameter, the shorter the emission wavelength.

  Boundaries between different color filter layers, that is, between the red color filter layer 25R and the green color filter layer 25G, between the green color filter layer 25G and the blue color filter layer 25B, and between the blue color filter layer 25B and the red color. A black matrix 28 is provided between the color filter layer 25R. The black matrix 28 is made of a known light-absorbing material, absorbs external light incident from the substrate 24 side, and prevents color mixing due to light incident from the liquid crystal light modulation element 3 side. The inner area surrounded by the black matrix 28 is the opening of each dot. The aperture ratio (area of the opening) of each dot may be different for each color.

  In the display device of this system, light emission by the phosphor is not used when the reflection mode is displayed using external light, and light emission by the phosphor is used when the transmission mode is displayed using light from the backlight. Therefore, basically, a phosphor layer is unnecessary in the reflective region of the liquid crystal cell, and a phosphor layer is necessary in the transmissive region.

  However, in the present embodiment, as shown in the upper side of FIG. 2, the phosphor layer 13 provided in the transmission region T protrudes into a part of the reflection region R. In other words, as shown in the lower side of FIG. 2, the reflective film 12 and the phosphor layer 13 partially overlap when viewed from the normal direction of the first substrate 9 and the second substrate 10. That is, the phosphor layer 13 is provided on the entire transmission region T. On the other hand, in the reflective region R, the phosphor layer 13 is provided on the side near the transmissive region T, and the phosphor layer 13 is not provided on the side far from the transmissive region T. In addition, the formation area of the phosphor layer 13 is indicated by a symbol K.

  In addition, the reflection region R is provided in a direction along the boundary between the dots to which the reflection region R belongs and the dots that display different colors among the four boundary lines between the dots adjacent to the four sides. That is, of the four sides of the rectangular dots, the two upper and lower sides extending in the horizontal direction (lateral direction) are boundary lines with dots that perform the same color display. On the other hand, the two left and right sides extending in the vertical direction (longitudinal direction) are boundaries between dots that display different colors. The reflection region R is formed so as to extend in a direction parallel to the left and right sides extending in the vertical direction (longitudinal direction). The boundary between the reflection region R and the transmission region T extends in parallel with the two left and right sides extending in the vertical direction (longitudinal direction).

  The arrangement of the scatterer layer 26 is the same as that of the phosphor layer 13. That is, the scatterer layer 26 provided in the transmission region T protrudes into a part of the reflection region R. In other words, the reflective film 12 and the scatterer layer 26 partially overlap each other when viewed from the normal direction of the first substrate 9 and the second substrate 10.

  As shown in FIG. 1, for the red dots DR and green dots DG, a partition wall 29 surrounding the side surface of the phosphor layer 13 is provided on the color filter 25. The cross-sectional shape of the partition wall 29 is a so-called forward tapered shape in which the width on the distal end side is narrower than the width on the proximal end side in contact with the color filter 25. Light scattering particles are dispersed inside the partition walls 29. Specifically, the partition wall 29 is formed of a material containing a resin and light scattering particles. In the present embodiment, the entire partition wall 29 is formed of a material containing resin and light scattering particles, but is not limited thereto. For example, only the portion of the partition wall 29 in contact with the phosphor layer 13 may be formed of a material containing resin and light scattering particles. That is, it is only necessary that at least a portion of the partition wall 29 in contact with the phosphor layer 13 has light scattering properties. Also in the blue dot DB, the partition wall 29 surrounding the side surface of the scatterer layer 26 is provided in the same manner as the red dot DR and the green dot DG.

  The color of the partition wall 29 may be white. Specifically, the partition wall 29 may include a white resist. The entire partition wall 29 may contain a white resist, or only the portion of the partition wall 29 that is in contact with the phosphor layer 13 may contain a white resist. That is, it is sufficient that at least a portion of the partition wall 29 in contact with the phosphor layer 13 is white. Thereby, compared with the case where the partition wall 29 is black, the light emitted from the phosphor layer 13 can be made difficult to be absorbed by the partition wall 29.

  For the red dots DR and green dots DG, a transparent resin layer 30 having substantially the same thickness as that of the phosphor layer 13 is provided in a region of the reflection region R where the phosphor layer 13 is not provided. With this configuration, the space surrounded by the partition walls 29 is embedded at a height substantially equal to the phosphor layer 13 by the transparent resin layer 30, and the surface of the phosphor substrate 4 is flattened. The transparent resin layer 30 may be formed not only in a region where the phosphor layer 13 is not provided, but also to embed the upper surface of the phosphor layer 13. According to this configuration, the surface of the phosphor substrate 4 is further planarized. Also in the blue dot DB, the transparent resin layer 30 having substantially the same thickness as the scatterer layer 26 is provided in a region where the scatterer layer 26 is not provided, similarly to the red dot DR and the green dot DG.

Hereinafter, the display principle of the display device 1 of the present embodiment will be described.
FIG. 3A is a diagram for explaining the display principle in the transmission mode, and FIG. 3B is a diagram for explaining the display principle in the reflection mode.

  In the display device 1 of the present embodiment, the alignment state of the liquid crystal molecules 8 </ b> B constituting the liquid crystal layer 8 changes according to the potential difference with the counter electrode 19 when a predetermined potential is applied to the pixel electrode 15. In the transmission mode display, as shown in FIG. 3A, light from the backlight 2 passes through the first polarizing plate 6 and the first retardation plate 22 and is converted into circularly polarized light. The polarization state of the circularly polarized light changes according to the alignment state of the liquid crystal molecules 8B, and the amount of light transmitted through the second polarizing plate 7 is controlled. Thereafter, the phosphor layer 13 is excited by the light transmitted through the second polarizing plate 7, and predetermined color light is emitted to the viewing side.

  In the reflection mode display, as shown in FIG. 3B, external light passes through the second polarizing plate 7 and the second retardation plate 18 and is converted into circularly polarized light. The polarization state of the circularly polarized light changes according to the alignment state of the liquid crystal molecules 8B, and the amount of light when the light is again transmitted through the second polarizing plate 7 after being reflected by the reflective film 12 is controlled. Here, since the phase difference of the liquid crystal layer 8 in the reflection region R is set to approximately ½ of the phase difference of the liquid crystal layer 8 in the transmission region T, the transmission mode is applied when a predetermined potential is applied to the pixel electrode 15. The same display is performed in the reflection mode.

  In the display device 1 of the present embodiment, the red color filter layer 25R is provided on the viewing side of the red phosphor layer 13R, and the green color filter layer 25G is provided on the viewing side of the green phosphor layer 13G. Therefore, blue light components contained in external light such as sunlight and illumination light are absorbed by the red color filter layer 25R and the green color filter layer 25G, and hardly reach the red phosphor layer 13R and the green phosphor layer 13G. As a result, it is possible to provide a display device in which excitation of the red phosphor layer 13R and the green phosphor layer 13G due to external light is suppressed, and the contrast ratio does not easily decrease even in a bright environment.

  In a dark environment, the transmission mode is displayed by the light of the backlight 2. At this time, the spectrum of the red light, the green light emitted from each phosphor layer 13 and the blue light transmitted through the scatterer layer 26 is close to the transmission spectrum of the color filter 25, so that these lights make the color filter 25 highly efficient. It penetrates with. Due to the above effects, in this embodiment, a clear display is possible regardless of the brightness of the environment, and a display device with excellent light utilization efficiency can be provided.

Further, in the case of the present embodiment, the phosphor layer 13 in the transmission region T partially protrudes from the reflection region R, so that the following effects are obtained.
Consider the transmission mode. As described above, it is desirable to use the backlight 2 having high directivity. However, even when the backlight 2 having high directivity is used, as shown in FIG. 3A, there is not a little light that is transmitted obliquely through the liquid crystal layer 8. For example, there is light that travels obliquely from the transmission region T toward the reflection region R, such as the light indicated by the symbol L1. In this case, since the phosphor layer 13 protrudes into the reflection region R, part of such light L1 reaches the phosphor layer 13 and contributes to light emission. As a result, the amount of transmitted light can be increased. Further, a part of the light L2 traveling backward from the phosphor layer 13 propagates to the reflection region R, and the light L3 reflected by the reflective film 12 is emitted to the viewing side through the transparent resin layer 30 and the color filter 25. The amount of transmitted light can also be improved by this light L3.

Consider the reflection mode. Since the phosphor layer 13 protrudes into the reflection region R, a part of the light L4 incident on the peripheral portion of the reflection region R sequentially passes through the color filter 25 and the phosphor layer 13 and enters the liquid crystal layer 8. The light L5 reflected by the reflective film 12 is emitted to the viewing side through the transparent resin layer 30 and the color filter 25. As a result, the amount of reflected light can be improved. Further, the color filter 25 is arranged on the viewer side with respect to the second polarizing plate 7, and the second polarizing plate 7 -the reflective film 12 -the second polarizing plate 7, which is a light path in the reflective region R. It does not exist in the route. Therefore, the polarization state of the light is not disturbed in the above path due to the depolarization of the color filter 25. As a result, the contrast ratio of the reflective display can be improved.
As described above, bright display can be obtained in each of the reflection mode and the transmission mode.

[First Modification]
FIG. 4 is a cross-sectional view of a display device according to a first modification of the present embodiment.
In FIG. 4, the same reference numerals are given to the same components as those in FIG.

  In the above embodiment, the phosphor layer 13 and the scatterer layer 26 are provided in part of the transmission region T and the reflection region R. On the other hand, in the display device of this modification, as shown in FIG. 4, the phosphor layer 13 is provided on the entire surface over both the transmissive region T and the reflective region R. Thereby, the reflective film 12 entirely overlaps the phosphor layer 13. According to this configuration, it is not necessary to pattern the phosphor layer 13 at the boundary between the transmission region T and the reflection region R. The scatterer layer 26 may be provided on the entire surface of the transmission region T and the reflection region R, or may be provided on a part of the transmission region T and the reflection region R.

[Second Modification]
FIG. 5 is a plan view showing one dot in the display device of the second modified example of the present embodiment.
In FIG. 5, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the above embodiment, the reflective film 12 and the phosphor layer 13 are provided over substantially the entire longitudinal direction of the rectangle indicating the outline of the dots. On the other hand, in the display device according to this modification, as shown in FIG. 5, the reflective film 12 is not provided on the entire boundary between the reflective region R and the transmissive region T. In the reflective region R, there is a region where the reflective film 12 is not provided at the boundary between the reflective region R and the transmissive region T.

[Third Modification]
FIG. 6 is a cross-sectional view showing a phosphor substrate in a display device according to a third modification of the present embodiment.
In the display device of this modification, the backlight and the liquid crystal light modulation element are the same as those in the above embodiment, and only the configuration of the phosphor substrate is different.
In FIG. 6, the same components as those in FIG.

  In the phosphor substrate 4 of the above embodiment, the cross-sectional shape of the partition wall 29 is a so-called forward tapered shape in which the width on the distal end side is narrower than the width on the proximal end side in contact with the color filter 25. On the other hand, in the phosphor substrate 33 of this modification, as shown in FIG. 6, the cross-sectional shape of the partition wall 34 is so-called that the front end side is wider than the base end side width in contact with the color filter 25. Inverted taper shape. In this case, the side surface of the partition wall 34 is inclined toward the substrate 24 side. With this configuration, since the light emitted from each phosphor layer 13 is reflected by the partition walls 34 and then travels toward the substrate 24, the extraction efficiency of the light emitted from each phosphor layer 13 can be improved. Note that a structure made of a material having a refractive index lower than that of the phosphor layer 13 may be provided in place of the partition wall 34 having light scattering property or light reflection property.

[Fourth Modification]
FIG. 7 is a cross-sectional view showing a phosphor substrate in a display device according to a fourth modification of the present embodiment.
In the display device of this modification, the backlight and the liquid crystal light modulation element are the same as those in the above embodiment, and only the configuration of the phosphor substrate is different.
In FIG. 7, the same components as those in FIG.

  As shown in FIG. 7, the phosphor substrate 37 of the present modification is covered with a low refractive index layer 38 made of a material having a refractive index lower than that of the phosphor layer 13. That is, the phosphor substrate 37 of this modification is obtained by adding the low refractive index layer 38 to the phosphor substrate 33 shown in FIG. According to this modification, since the light emitted from the phosphor layer 13 is reflected by the low refractive index layer 38 and then travels toward the substrate 24, the extraction efficiency of the light emitted from the phosphor layer 13 is improved. Can do.

[Fifth Modification]
FIG. 8 is a cross-sectional view showing a phosphor substrate in a display device according to a fifth modification of the present embodiment.
In the display device of this modification, the backlight and the liquid crystal light modulation element are the same as those in the above embodiment, and only the configuration of the phosphor substrate is different.
In FIG. 8, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 8, the phosphor substrate 41 of the present modification is covered with a low refractive index layer 38 made of a material having a refractive index lower than that of the phosphor layer 13. Further, the periphery of the low refractive index layer 38 is covered with the color filter 25. That is, in the phosphor substrate 37 of the fourth modification example, the phosphor layer 13 is laminated on the color filter 25, but in the phosphor substrate 41 of this modification example, the phosphor layer 13 is disposed inside the color filter 25. It is an embedded form. Also in this modified example, since the light emitted from the phosphor layer 13 is reflected by the low-refractive index layer 38 and then travels toward the substrate 24 as in the fourth modified example, the light emitted from the phosphor layer 13 The extraction efficiency can be improved. In addition, with this configuration, the phosphor substrate 41 can be thinned.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the display device of this embodiment is the same as that of the first embodiment, and the arrangement of the reflective region and the transmissive region in one dot is different from that of the first embodiment.
FIG. 9 is a plan view showing one dot in the display device of the present embodiment.
10A and 10B are diagrams for explaining the effect of the display device of this embodiment. FIG. 10A shows the action of light in the display device of this embodiment, and FIG. 10B shows the display of the first embodiment. The action of light in the device is shown respectively.
9 and 10, the same reference numerals are given to the same components as those in FIG. 2, and detailed description thereof will be omitted.

  In the display device 44 of the present embodiment, as shown in FIG. 9, the reflection region R is provided along the four sides of the outer periphery of the dot DR in one dot DR. The transmissive region T is provided at the center of the dot DR and is surrounded by a reflective region R provided along the four outer sides. The reflection film 12 and the phosphor layer 13 partially overlap, and the region where the reflection film 12 and the phosphor layer 13 overlap has an annular shape.

10A and 10B depict two dots, for example, the left dot indicates a red dot DR and the right dot indicates a blue dot DB.
In the case of the display device 1 of the first embodiment, as shown in FIG. 10B, the reflective region R and the transmissive region T are provided along the boundary of dots that perform display of different colors. That is, the reflective film 12 and the phosphor layer 13 are provided along the boundary of dots that perform display of different colors. For this reason, out of the light obliquely transmitted through the transmission region T of the red dot DR, the light L1 that is obliquely transmitted toward the blue dot DB side is transmitted through the transparent resin layer 30 of the blue dot DB and is emitted from the blue dot DB. Is done.

  Of the external light that is obliquely incident from the blue dot DB, the light L2 that is obliquely incident toward the red dot DR side is the reflective film 12 of which the blue light component transmitted through the blue color filter layer 25B is the blue dot DB. The reflected light L3 is incident on the red phosphor layer 13R of the red dot DR. Then, the red phosphor layer 13R is excited to generate fluorescence, and light L4 is emitted from the red dot DR. As described above, since light is emitted from unintended color dots, there is a possibility that problems such as a decrease in color purity and occurrence of color blur may occur.

  On the other hand, in the display device 44 of the present embodiment, as shown in FIG. 10A, the transmission region T is provided in the center of the dots DR and DB, and the reflection region R surrounds the transmission region T. It is provided at the periphery of the dots DR and DB. Therefore, the light L5 transmitted obliquely through the transmission region T of the red dot DR stops in the red dot DR and does not reach the blue dot DB.

  Of the external light incident obliquely from the blue dot DB, the light L6 traveling obliquely toward the red dot DR side reflects the blue light component transmitted through the blue color filter layer 25B by the reflective film 12 of the blue dot DB. Then, the reflected light L7 may enter the red dot DR. However, in the present embodiment, since the red phosphor layer 13R is disposed at the center of the red dot DR, the light reflected by the reflective film 12 of the blue dot DB and incident on the red dot DR is the red phosphor layer. The rate of incidence on 13R is reduced compared to the first embodiment. As a result, according to the display device 44 of the present embodiment, it is possible to improve problems such as a decrease in color purity and the occurrence of color blurring caused by light being emitted from unintended color dots.

[First Modification]
FIG. 11 is a plan view of one dot in the display device according to the first modification of the present embodiment.
In FIG. 11, the same components as those in FIG. 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the above embodiment, the reflection region R is provided along all the sides of the outer periphery of the dot DR, and the entire periphery of the transmission region T is surrounded by the reflection region R. On the other hand, in the display device of the present modification, as shown in FIG. 11, the reflective region R has two sides adjacent to the dots that display different colors, that is, the left and right two extending in the vertical direction. It is provided along the side. The transmission region T is provided at the center of the dot DR, and only the direction (horizontal direction) in which dots for displaying different colors are arranged is surrounded by the reflection region R.

  Also in this modification, the cross-sectional view when the dots are cut along the direction (horizontal direction) in which dots for displaying different colors are arranged is the same as that in the above embodiment. Therefore, as described with reference to FIG. 10A, problems such as a decrease in color purity and occurrence of color blur due to light being emitted from unintended color dots can be improved.

[Second Modification]
FIG. 12 is a plan view of one dot in the display device according to the second modified example of the present embodiment.
In FIG. 12, the same components as those in FIG. 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the above embodiment, the reflection region R is provided along all the sides of the outer periphery of the dot DR, and the entire periphery of the transmission region T is surrounded by the reflection region R. On the other hand, in the display device of the present modification, as shown in FIG. 12, the reflective region R is adjacent to the two sides adjacent to the dots that display different colors and the dots that display the same color. It is integrally provided along a total of three sides, one side on the mating side, that is, two sides on the left and right extending in the vertical direction and one side on the upper side extending in the horizontal direction. The transmission region T is provided at the center of the dot DR, and three sides are surrounded by the reflection region R.

  Also in this modification, the cross-sectional view when the dots are cut along the direction (horizontal direction) in which dots for displaying different colors are arranged is the same as that in the above embodiment. Therefore, as described with reference to FIG. 10A, problems such as a decrease in color purity and occurrence of color blur due to light being emitted from unintended color dots can be improved.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the display device of this embodiment is the same as that of the first embodiment, and is different from the first embodiment only in that a microlens array is added.
FIG. 13 is a cross-sectional view of the display device of this embodiment.
In FIG. 13, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the display device 47 of the present embodiment, as shown in FIG. 13, a microlens array 48 is provided between the first substrate 9 and the first retardation plate 22 constituting the liquid crystal cell 5. . The micro lens array 48 has the same number of micro lenses 49 as the number of dots on a sheet-like member. The microlens array 48 is designed so that each microlens 49 is positioned below the transmission region T of one dot DR, DG, DB. The light emitted from the backlight 2 is condensed by the microlens 49 on the transmission region T of each dot DR, DG, DB. In FIG. 13, the microlens array 48 is in close contact with the first substrate 9, but the microlens array 48 is not necessarily in close contact with the first substrate 9. The “microlens array” in the present embodiment corresponds to a “light collecting member” in the claims.

  In the display device 47 of the present embodiment, the light emitted from the backlight 2 is condensed on the transmission regions T of the dots DR, DG, and DB by the microlenses 49 of the microlens array 48. Can contribute more to the display of the transmission mode. Thereby, the light utilization efficiency of the backlight 2 is improved, and a bright display can be obtained in the transmission mode. Note that the light collecting member is not necessarily limited to the microlens array, and for example, a light collecting member using a concave mirror or the like may be used.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the display device of this embodiment is the same as that of the first embodiment, and is different from the first embodiment only in that a bandpass filter is added.
FIG. 14 is a cross-sectional view of one dot in the display device of the present embodiment.
In FIG. 14, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the display device 52 of the present embodiment, as shown in FIG. 14, a band pass filter 53 is provided on the optical path between the phosphor layer 13 or the scatterer layer and the second polarizing plate 7. The bandpass filter 53 has a wavelength selection characteristic that transmits light in the wavelength band of blue light and reflects light in a wavelength band other than the wavelength band of blue light. The “bandpass filter” of the present embodiment corresponds to a “wavelength selective transmission layer” in the claims.

  Since light is emitted isotropically from the phosphor layer 25, there is a problem that it is difficult to contribute to the display light emitted backward from the phosphor layer 13. For this problem, since the display device 52 of the present embodiment includes the band-pass filter 53, the blue light from the backlight 2 passes through the band-pass filter 53, while facing backward from the phosphor layer 13. The emitted red light and green light are reflected by the band pass filter 53. Thereby, the extraction efficiency of the light emitted from the phosphor layer 13 is improved, and a bright display can be obtained in the transmission mode.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the display device of this embodiment is the same as that of the first embodiment, and only the point that a reflective polarizing plate is used as the first polarizing plate is different from the first embodiment.
FIG. 15 is a cross-sectional view of one dot in the display device of this embodiment.
In FIG. 15, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the display device 1 of the first embodiment, an absorptive polarizing plate is used as the first polarizing plate 6. On the other hand, in the display device 56 of the present embodiment, as shown in FIG. 15, the reflected light is reflected as the first polarizing plate 57 on the optical path between the backlight 2 and the first retardation plate 22. A board is provided. The reflective polarizing plate has a characteristic of transmitting the first linearly polarized light having a predetermined polarization direction and reflecting the second linearly polarized light having a polarization direction orthogonal to the polarization direction of the first linearly polarized light. In the present embodiment, the liquid crystal light modulation element 58 is configured by the first polarizing plate 57, the liquid crystal cell 5, and the second polarizing plate 7 made of a reflective polarizing plate.

  When an absorptive polarizing plate is used as the first polarizing plate, light that does not pass through the first polarizing plate is absorbed by the first polarizing plate and becomes light that does not contribute to display. On the other hand, in the case of the present embodiment, since the reflective polarizing plate is used as the first polarizing plate 57, the light that does not pass through the first polarizing plate 57 is reflected by the first polarizing plate 57. Return to backlight 2. Part of the light returned to the backlight 2 is reflected again by the back surface of the backlight or the like and returns to the first polarizing plate 57. At this time, since the polarization state of the light reaching the first polarizing plate 57 has changed immediately after reflection, a part of the light reaching the first polarizing plate 57 is transmitted through the first polarizing plate 57. The light contributes to display.

  Thus, in the display device 57 of the present embodiment, the light reflected by the first polarizing plate 57 can be reused, so that the light utilization efficiency of the backlight 2 can be improved. As a result, in the case of the display device 57 of the present embodiment, even if the same power is supplied to the backlight 2, a brighter display can be obtained compared to the first embodiment. Further, if the brightness of the display is the same as that of the first embodiment, the input power to the backlight 2 can be reduced as compared with the first embodiment.

[Sixth Embodiment]
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the display device of this embodiment is the same as that of the first embodiment, and the method of making the phase difference of the liquid crystal layer different between the transmission region and the reflection region is different from that of the first embodiment.
FIG. 16 is a cross-sectional view of one dot in the display device of this embodiment.
In FIG. 16, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, an integral pixel electrode 15 is provided in the transmissive region T and the reflective region R, and the same voltage is applied to the liquid crystal layer 8 in the transmissive region T and the liquid crystal layer 8 in the reflective region R. Then, by making the transmission cell thickness dT and the reflection cell thickness dR different, the phase difference of the liquid crystal layer 8 in the transmission region T and the phase difference of the liquid crystal layer 8 in the reflection region R are made different. On the other hand, in the display device 61 of this embodiment, as shown in FIG. 16, no insulating film is formed on the lower layer side of the reflective film 12, and the transmission cell thickness dT and the reflection cell thickness dR are substantially equal. . Separate pixel electrodes 15T and 15R are provided in the transmissive region T and the reflective region R. Further, TFTs, data lines and the like (not shown) are provided separately for each of the pixel electrodes 15T and 15R. With this configuration, different voltages are applied to the liquid crystal layer 8 in the transmissive region T and the liquid crystal layer 8 in the reflective region R.

  In the display device 61 of the present embodiment, by applying different voltages to the liquid crystal layer 8 in the transmissive region T and the liquid crystal layer 8 in the reflective region R, for example, the phase difference of the liquid crystal layer 8 in the reflective region R is changed to the transmissive region T. The phase difference of the liquid crystal layer 8 can be adjusted to approximately ½. Thereby, clear display can be realized in both the transmission mode and the reflection mode.

[Seventh Embodiment]
Hereinafter, a seventh embodiment of the present invention will be described with reference to FIG.
The basic configuration of the display device of this embodiment is the same as that of the first embodiment, and the configuration of the backlight and the blue dots is different from that of the first embodiment.
FIG. 17 is a cross-sectional view of the display device of this embodiment.
In FIG. 17, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, the backlight 2 that emits blue light is used, and in the blue dot DB, the blue light of the backlight 2 is used for display. Therefore, the scatterer layer 26 is used for the blue dot DB instead of the phosphor layer 13 used for the other dots DR and DG. On the other hand, as shown in FIG. 17, the display device 64 of the present embodiment includes a backlight 65 that emits light in a short wavelength region from the ultraviolet region to the blue wavelength region. The blue dot DB is provided with a blue phosphor layer 13B instead of the scatterer layer 26 of the first embodiment. The blue phosphor layer 13B includes a phosphor that is excited by the light in the short wavelength band and emits fluorescence in the blue wavelength band. In the present embodiment, the red phosphor layer 13R includes a phosphor that is excited by the light in the short wavelength region and emits fluorescence in the red wavelength region. The green phosphor layer 13G includes a phosphor that is excited by the light in the short wavelength region and emits fluorescence in the green wavelength region.

  The display device 64 of the present embodiment also provides the same effects as those of the first embodiment such that a clear display is possible regardless of the brightness of the environment, and a display device with excellent light utilization efficiency can be provided. It is done.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the display device of the above embodiment includes the second substrate that constitutes the liquid crystal cell between the second polarizing plate and the liquid crystal layer, but this substrate may not be included. In that case, the substrate of the phosphor substrate located closest to the viewing side functions as the second substrate of the liquid crystal cell. In that case, the second polarizing plate or the second retardation plate is an in-cell type polarizing layer or retardation layer formed on the inner surface side of the substrate.

In the above embodiment, an active matrix liquid crystal cell is used, but a passive matrix liquid crystal cell may be used instead. In the case of a passive matrix liquid crystal cell, a region where a pair of electrodes cross each other is a unit region constituting a display. Alternatively, a segment type liquid crystal cell may be used. In the case of a segment type liquid crystal cell, one segment is a unit region constituting a display.
In addition, the number, arrangement, shape, material, and the like of various components constituting the display device can be appropriately changed without being limited to the above-described embodiment.

  The present invention can be used in a display device suitable for use in applications such as digital signage (electronic signage) and a display unit of a portable device.

  DESCRIPTION OF SYMBOLS 1,44,47,52,56,61,64 ... Display apparatus, 2,65 ... Backlight (light source), 3,58 ... Liquid crystal light modulation element, 6 ... 1st polarizing plate, 7 ... 2nd polarization | polarized-light Plate: 8 ... Liquid crystal layer, 12 ... Reflective film, 13 ... Phosphor layer (wavelength conversion part), 13R ... Red phosphor layer, 13G ... Green phosphor layer, 13B ... Blue phosphor layer, 25 ... Color filter, 25R ... red color filter layer, 25G ... green color filter layer, 25B ... blue color filter layer, 48 ... microlens array (light collecting member), 53 ... band pass filter (wavelength selective transmission layer), 57 ... first polarizing plate (Reflective polarizing plate), DR: Red dot (unit region), DG ... Green dot (unit region), DB ... Blue dot (unit region), R ... Reflection region, T ... Transmission region.

Claims (15)

A light source that emits first light;
A liquid crystal light modulation element for controlling a transmission amount of the first light incident from the light source;
Second light having a wavelength band different from the wavelength band of the first light, which is provided on at least a part of the viewing side of the liquid crystal light modulation element and is excited by the first light incident from the liquid crystal light modulation element. A wavelength converter including a phosphor that emits light;
A color filter that is provided on the viewing side of the liquid crystal light modulation element and the wavelength conversion unit and transmits light in the wavelength band of the second light and absorbs light in a wavelength band other than the wavelength band of the second light And comprising
The liquid crystal light modulation element includes a liquid crystal layer, a first substrate disposed on the light source side of the liquid crystal layer, a second substrate disposed on the color filter side of the liquid crystal layer, and the liquid crystal layer Reflects light incident from the viewing side via the first polarizing plate disposed on the light source side, the second polarizing plate disposed on the color filter side of the liquid crystal layer, and the color filter and the liquid crystal layer. And a reflective film that
The liquid crystal light modulation element comprises a plurality of unit regions,
Each of the plurality of unit regions is a reflection region that is a formation region of the reflection film, a transmission region that is a non-formation region of the reflection film and transmits the first light toward the wavelength conversion unit, A display device comprising:   2. The display device according to claim 1, wherein the wavelength conversion unit and the reflective film are at least partially overlapped when viewed from the normal direction of the first substrate and the second substrate. In the reflection region, a phase difference plate is provided on the optical path between the color filter and the reflection film,
The retardation plate and the second polarizing plate constitute a circular polarizing plate that converts incident light into circularly polarized light,
3. The display device according to claim 1, wherein the retardation plate and the reflective film are at least partially overlapped when viewed from the normal direction of the first substrate and the second substrate. .   4. The display device according to claim 1, wherein at least a part of the reflection region includes a region where the wavelength conversion unit is not provided. 5.   5. The display device according to claim 4, wherein the plurality of unit regions include a plurality of unit regions arranged to display different colors arranged adjacent to each other.   The reflection area is provided in a direction along a boundary with a unit area for displaying different colors among a plurality of boundaries between a unit area to which the reflection area belongs and an adjacent unit area. The display device according to claim 5. The unit area is rectangular;
The reflective region is provided along two or more sides including two sides that are boundaries between the unit region for displaying different colors among the four sides of the unit region to which the reflective region belongs,
The display device according to claim 6, wherein the transmission region is provided in a central portion of the unit region and is surrounded by the reflection region provided along the two or more sides.   When the transmission amount of the first light in the liquid crystal light modulation element is maximum or minimum, the phase difference of the liquid crystal layer in the substrate normal direction in the transmission region is independent of the unit region that displays different colors. The display device according to claim 5, wherein the display device is approximately ½ of the wavelength of the first light.   When the transmission amount of the first light in the liquid crystal light modulation element is maximum or minimum, the phase difference of the liquid crystal layer in the substrate normal direction in the reflection region is displayed for each unit region displaying different colors. The display device according to claim 5, wherein the display device is approximately ¼ of a color wavelength. A first retardation plate is provided on an optical path between the liquid crystal layer and the first polarizing plate;
A second retardation plate is provided on the optical path between the liquid crystal layer and the second polarizing plate;
In the transmission region, the phase difference of the first retardation plate is approximately ¼ of the wavelength of the first light regardless of the unit region for displaying different colors.
The phase difference of the second retardation plate in the transmissive region is approximately ¼ of the wavelength of the first light regardless of a unit region for displaying different colors. Item 10. The display device according to any one of Items 5 to 9. A second retardation plate is provided on the optical path between the liquid crystal layer and the second polarizing plate;
11. The phase difference of the second retardation plate in the reflection region is approximately ¼ of the wavelength of the display color for each unit region for displaying different colors. The display device according to any one of the above. The first polarizing plate has a polarization characteristic corresponding to the wavelength band of the first light,
The display device according to claim 1, wherein the second polarizing plate has a polarization characteristic corresponding to the entire wavelength band of visible light.   The display according to any one of claims 1 to 12, further comprising a condensing member that condenses the first light emitted from the light source in the transmission region of the liquid crystal light modulation element. apparatus.   The light in the wavelength band of the first light is transmitted on the optical path between the second polarizing plate and the wavelength converter, and the light in the wavelength band other than the wavelength band of the first light is reflected. The display device according to claim 1, further comprising a wavelength selective transmission layer.   15. The reflective polarizing plate having a polarization characteristic corresponding to the wavelength band of the first light is provided on an optical path between the light source and the liquid crystal light modulation element. The display device according to one item.

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