JP2007011313A - Liquid crystal display device and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device that can increase light use efficiency during color display and is easy to manufacture, and a method of manufacturing the liquid crystal display device. <P>SOLUTION: The liquid crystal display device 100 includes: a transmission type display panel 11 which has a plurality of pixels defined, each of the plurality of pixels including a first pixel where a first color filter transmitting first color light is arranged and a second pixel where a second color filter transmitting second color light different from the first color light is arranged; and a back light unit 10 which supplies light to the liquid crystal display panel 11. On the surface of the liquid crystal display panel on the side of the back light unit, a first diffraction grating portion is formed in the area of the first pixel and a second diffraction grating portion is formed in the area of the second pixel respectively. A diffraction grating portion of each pixel is arranged having such a positional relation that primary diffracted light is made incident on color filters of adjacent pixels. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and a method for manufacturing the same.

  The display area of the color liquid crystal display device is composed of hundreds of thousands to hundreds of thousands of pixels. Each pixel is composed of red, green, and blue, that is, R, G, and B picture elements (also referred to as “sub-pixels”). Each picture element is provided with a color filter of a corresponding color among R, G, and B. By controlling the alignment state of the liquid crystal in each picture element, it is possible to adjust how much light incident on the area of each picture element is transmitted. The light that passes through the liquid crystal layer of each picture element always passes through the color filter corresponding to the picture element before or after the liquid crystal layer, so that the light of the color of the picture element is finally emitted. The

  Each picture element only controls the transmittance of the liquid crystal layer with respect to light for developing one color of RGB, but one pixel contains picture elements for three colors. One pixel can display light in which three colors of RGB are combined at a desired ratio. A full-color image is obtained as an aggregate of display with such pixels. However, since light passes through not only the liquid crystal layer but also the color filter in each picture element, 2/3 of the light amount is absorbed when passing through the color filter. Therefore, theoretically, only 1/3 of the light amount is used for image display.

  In order to avoid light loss due to the color filter, a method of performing color display without using a color filter is known in which light is separated into light of a plurality of wavelength regions and condensed for each light of each wavelength region. Yes. For example, there exists a technique currently disclosed by Unexamined-Japanese-Patent No. 2000-241812 (patent document 1). In the configuration shown in FIG. 1 of this patent document, in a liquid crystal display device including a liquid crystal display panel and a backlight device, each of the RGB colors is transmitted by providing a diffraction grating on the light guide of the backlight device. The light is diffracted so as to be separated into different diffraction angles and emitted from the backlight device. Light emitted from the backlight device is incident on a cylindrical lens array provided on the surface of the liquid crystal display panel. The cylindrical lens array guides incident light of each color to the corresponding picture element.

  Further, a method of separating RGB colors by controlling the groove depth and structure of the diffraction grating is described in “Color Separation gratings”, Applied Optics, Vol. 17, No. 15, pp. 2273-2279 (Non-patent Document 1). And “Stripe color separation with diffractive optics”, Applied Optics, Vol.38, No.35, pp.7193-7201 (Non-patent Document 2). In the former, white light is incident on the multilevel grating structure, and G light is generated with zero-order light, R light is generated with primary light, and B light is generated with −1st-order light. The latter is an extension of the former, uses a multi-level grating structure, and further changes the lattice depth and lattice pitch in units of picture elements. This function will be described with reference to FIG. In the following, “R light”, “G light”, and “B light” mean red light, green light, and blue light, respectively.

By setting the grating depth of the diffraction grating 41 having the multi-level grating structure, a region 41R for transmitting and transmitting the R light linearly, a region 41G for transmitting and transmitting the G light linearly, and a region 41B for transmitting and transmitting the B light linearly are formed. The diffraction grating pitch is set so that the zero-order light in the region 41G, the first-order diffracted light in the region 41R, and the −1st-order diffracted light in the region 41B overlap at a position away from the diffraction grating 41 by the distance D. A diffraction grating 41 is provided on the liquid crystal display panel, and the color filter 46 of the liquid crystal display panel is arranged at a position separated from the diffraction grating 41 by a distance D. In such a liquid crystal display panel, G light is incident on the G light element, R light is incident on the R light element, and B light is incident on the B light element. Light loss can be reduced.
JP 2000-241812 A "Color Separation gratings", Applied Optics, Vol.17, No.15, pp.2273-2279 (August 1, 1978) "Stripe color separation with diffractive optics", Applied Optics, Vol.38, No.35, pp.7193-7201 (December 10, 1999)

  In the configuration described in Patent Document 1, since the optical axes of the principal rays of the RGB light beams emitted from the diffraction grating of the backlight device are inclined, the color changes depending on the viewing direction. There's a problem. That is, depending on the viewing direction, the R light appears strong or the B light appears strong. As a solution, providing a diffusion plate is described in paragraph 0025 of Patent Document 1, but this measure alone does not have a sufficient effect.

  Similarly, when the color separation method according to Non-Patent Document 1 is used, the optical axis of the principal ray of each color is similarly inclined, so that the color changes depending on the viewing direction.

  On the other hand, in the configuration described in Non-Patent Document 2, white light is color-separated into three colors of RGB in stripes, and the optical axes of the principal rays of each color light are aligned, so the color changes depending on the viewing direction. There is no problem of appearing. However, if this technique is to be applied, precise alignment between the diffraction grating and the liquid crystal display panel is required. In liquid crystal display panels for mobile applications, the pixel pitch is as small as a few tens of μm and the pixel pitch is 1/3 of that, so alignment with a precision of several μm is required between the diffraction grating and the liquid crystal display panel. It is. In Non-Patent Document 2, a three-stage multilevel diffraction grating is used, but it is difficult to form a three-stage multilevel diffraction grating with a pitch of 4 to 5 μm, and even if it can be formed, the necessary process is complicated. It will be a thing.

  Therefore, an object of the present invention is to provide a liquid crystal display device and a method for manufacturing the liquid crystal display device that can improve the light use efficiency during color display and are easy to manufacture.

  In order to achieve the above object, in the liquid crystal display device according to the present invention, a plurality of pixels are defined, and each of the plurality of pixels has a first picture in which a first color filter that transmits a first color light is arranged. A transmission type liquid crystal display panel including a plurality of picture elements including a first color element and a second picture element on which a second color filter that transmits a second color light different from the first color light is disposed; and And a backlight device that supplies light toward. On the surface of the liquid crystal display panel on the backlight device side, a first diffraction grating portion is formed in the first pixel region and a second diffraction grating portion is formed in the second pixel region. The first diffraction grating portion has a property of causing the first color light to travel straight and diffracting light other than the first color light. The second diffraction grating portion has a property of causing the second color light to travel straight and diffracting light other than the second color light. The diffraction grating portions of the picture elements are arranged in a positional relationship such that the first-order diffracted light enters the color filter of the adjacent picture element.

  In order to achieve the above object, a manufacturing method of a liquid crystal display device according to the present invention defines a plurality of pixels, and each of the plurality of pixels includes a plurality of picture elements. A first color filter that transmits the first color light is arranged in the first picture element, and the second color element different from the first picture element in the plurality of picture elements is the first color light. A step of preparing a transmission type liquid crystal display panel in which a second color filter that transmits different second color light is disposed, and a step of forming a photosensitive resin layer on the surface of the liquid crystal display panel that is to be on the backlight device side The liquid crystal display panel emits curing light that can cure the photosensitive resin layer, transmit the first color filter, and transmit the second color filter. With respect to the incident angle A step of partially curing the photosensitive resin layer by irradiating while changing, and a first diffraction grating portion in the region of the first picture element of the photosensitive resin layer by pressing a diffraction grating mold And forming a second diffraction grating portion in the region of the second picture element in the photosensitive resin layer.

  In the liquid crystal display device according to the present invention, the first color light that has been transmitted so as to travel straight through the first diffraction grating portion and the first color light diffracted by the second diffraction grating portion are incident on the first color filter, The second color light transmitted so as to travel straight through the second diffraction grating portion and the second color light diffracted by the first diffraction grating portion are incident on the color filter. Therefore, the light use efficiency can be increased. In addition, since the central optical axis of each emitted light is in a direction perpendicular to the liquid crystal display panel, there is no problem that the color changes when viewed obliquely.

(Embodiment 1)
(Constitution)
With reference to FIGS. 1-4, the liquid crystal display device in Embodiment 1 based on this invention is demonstrated. As shown in FIG. 1, the liquid crystal display device 100 includes a transmissive liquid crystal display panel 11 and a backlight device 10. The backlight device 10 includes a light source 1, a light guide plate 2, and a prism sheet 3. The prism sheet 3 is disposed so as to cover the surface of the light guide plate 2 on the liquid crystal display panel 11 side. The light source 1 is disposed along the side surface of the light guide plate 2. As the light source 1, for example, a combination of RGB three-color LEDs may be used.

  The liquid crystal display panel 11 includes two transparent substrates 4 and 5 and a liquid crystal layer (not shown) interposed therebetween. The transparent substrates 4 and 5 may be glass substrates. A color filter layer 6 is formed on the surface of the transparent substrate 4 on the liquid crystal layer side. A plurality of pixels are defined in the display area of the liquid crystal display panel 11. The number of pixels may be from tens of thousands to hundreds of thousands. Each of the plurality of pixels is composed of R, G, B picture elements. The three color R, G, and B picture elements are hereinafter referred to as “R picture element”, “G picture element”, and “B picture element”, respectively. Each picture element has an opening for transmitting light. However, a color filter is stretched in the region that transmits this light. A color filter 6R that transmits R light and absorbs G light and B light is stretched at the opening of the R picture element. A color filter 6G that transmits G light and absorbs R light and B light is stretched in the opening of the G picture element. A color filter 6B that transmits B light and absorbs R light and G light is stretched through the opening of the B picture element. In the liquid crystal display device 100, a full-color image is obtained by combining the transmitted light of these three RGB picture elements included in each pixel.

  Although not shown in FIG. 1, the liquid crystal display panel 11 further includes members such as a TFT circuit, a polarizing plate, and a phase difference compensation plate.

A diffraction grating layer 12 is formed on the surface of the liquid crystal display panel 11 on the backlight device 10 side. The diffraction grating of the diffraction grating layer 12 is also called a “color separation diffraction grating”. The diffraction grating layer 12 has a different structure for each RGB picture element. FIG. 2 shows an enlarged view of a region corresponding to one pixel of the diffraction grating layer 12. As shown in FIG. 2, the diffraction grating layer 12 includes diffraction grating portions 12R, 12G, and 12B. The diffraction grating portions 12R, 12G, and 12B are arranged in the R, G, and B picture element regions, respectively. When each diffraction grating portion is enlarged, it is formed as a periodic protrusion as shown in FIG. Each diffraction grating portion is formed of a photosensitive resin. The grating thickness d _G of the diffraction grating portion 12G in the G picture element region is designed to satisfy the formula (1).
(N ₁ −n ₂ ) × d _G = Lλ _G (L is a natural number) (1)
Here, n ₁ and n ₂ are the refractive index of the material constituting the flesh portion of the diffraction grating layer 12 and the refractive index of the medium satisfying the gap portion. λ _G is the center wavelength of G light. “Grating thickness” is the thickness of the diffraction grating portion 12G in the vertical direction as shown in FIG.

The grating thickness d _G of the diffraction grating portion 12G causes the incident G light to travel straight and guide it to the color filter 6G, while the R light and B light other than the G light are diffracted and the R picture element adjacent to the G picture element, The thickness is such that it leads to the color filters 6R and 6B of the B picture element. Similarly, the grating thickness d _R of the diffraction grating portion 12R in the R picture element region is such that the R light travels straight and the G light and B light are diffracted. The grating thickness d _B of the diffraction grating portion 12B in the B picture element region is such that the B light travels straight and diffracts the R light and G light. In order for each diffraction grating portion to satisfy these conditions, for example, when the material of the flesh portion of the diffraction grating layer 12 is a resin having a refractive index of 1.6 and the medium filling the gap is air, The lattice thicknesses d _R , d _G , and d _R of the lattice portions 12R, 12G, and 12B may be designed according to Table 1. FIG. 4 shows the relationship between wavelength and diffraction efficiency in each diffraction grating portion at this time.

  Since the grating thickness of the diffraction grating portion matches the grating depth, the fact that the grating thickness of the diffraction grating portion arranged in each picture element is different means that the grating depth in each picture element is different. means.

As shown in FIG. 2, the diffraction grating portion 12R, 12G, grating pitch of 12B has a common value pitch P _G. The grating pitch P _G is first-order diffracted light diffracted by the diffraction grating portion 12G is designed in principle that such incident on pixels of the color filters adjacent each. Accordingly, the grating pitch P _G has the formula (2) is determined so as to satisfy (3).
tan θ _d = P _P / D (2)
n ₃ sin θ _d = λ / P _G (3)
Here, n ₃ is the refractive index of the glass substrate, θ _d is the diffraction angle of the diffracted light in the glass substrate, P _P is the pixel pitch of the liquid crystal display panel 11, and D is the distance between the diffraction grating and the color filter. It is. In FIG. 2, a liquid crystal layer, a TFT circuit, and the like between the color filters 6R, 6G, and 6B and the transparent substrate 5 are not shown, but D denotes a diffraction grating and a color that face each other with these components interposed therebetween. The distance to the filter. Furthermore, λ is the wavelength of light. Diffraction angles differ slightly depending on the wavelength, by optimizing the grating pitch P _G in accordance with the G light, R light emitted as a first-order diffracted light, for the B light incident slightly away from the picture elements adjacent However, the amount of deviation is about 10 to 20%, which is small and is allowed.

The reason why _G of the three colors is used as a reference when determining the grating pitch PG is that the G light is in the middle when considering the magnitude relationship of the wavelengths of the light of each RGB color. In this case, since the grating pitch is determined based on the wavelength of the G light, a slight deviation occurs in the R picture element and the B picture element, but this deviation is small, and the merit by unifying the grating pitch Since is larger, it is allowed.

(Action / Effect)
Actions and effects brought about by the liquid crystal display device in this embodiment will be described. In FIG. 1, light emitted from the light source 1 enters the light guide plate 2 from the end face of the light guide plate 2 and propagates through the light guide plate 2 while repeating total reflection on the upper and lower surfaces of the light guide plate 2. Microstructures called microdots are randomly provided on the upper surface of the light guide plate 2. The light leaked upward without satisfying the total reflection condition by the microdots is guided by the prism sheet 3 in a direction perpendicular to the upper surface of the prism sheet 3 and is emitted from the backlight device 10 as light 13.

  The light 13 emitted from the backlight device 10 enters the diffraction grating layer 12. Of the light 13, attention is focused on light incident on the diffraction grating portion 12 </ b> G of the G picture element. The light 13 includes components of R light, G light, and B light. In FIG. 1 and FIG. 2, hatching applied to an arrow indicating light indicates color distinction. The same applies to the hatching applied to the color filter.

  Of the light 13 incident on the diffraction grating portion 12G, the G light travels straight and is guided to the color filter 6G. Of the light 13 incident on the diffraction grating portion 12G, the R light and the B light are each diffracted in two directions and guided to the color filters 6R and 6B of the adjacent picture elements. On the other hand, the G light included in the light 13 incident on the diffraction grating portion 12R is diffracted in two directions and guided to the color filters 6B 'and 6G of adjacent picture elements. The G light included in the light incident on the diffraction grating portion 12B is diffracted in two directions and guided to the adjacent color filters 6G and 6R ″.

  Thus, the G light guided to the color filter 6G of the G picture element passes through the color filter 6G as it is, whether it is a straight light or a diffracted light. The G light guided to the color filters 6R ″ and 6B ′ of the R picture element and the B picture element is absorbed by the color filters 6R ″ and 6B ′. The same phenomenon occurs for R light and B light.

  The light utilization efficiency in this embodiment will be described. In the conventional liquid crystal display device, since the loss due to the color filter was 2/3, the light use efficiency remained at 1/3 or less. On the other hand, in the present embodiment, the G light incident on the diffraction grating portion 12G is transmitted without loss, and part of the G light incident on the diffraction grating portions 12R and 12B is also guided to the color filter 6G as diffracted light. It is burned. In other words, the color filter 6G receives three types of light, G light traveling straight from the diffraction grating portion 12G and G light traveling as first-order diffracted light from the diffraction grating portions 12R and 12B of adjacent picture elements, respectively. Will be.

  Here, attention is paid to G light, but the same effect can be obtained for R light and B light. When the diffraction grating is designed so that the primary diffraction efficiency is 30 to 40%, the average diffraction efficiency is considered to be 35%, and the light utilization efficiency is 1 + 35/100 × 2 = 1.7. In other words, the light utilization efficiency as a whole can be increased to 1.7 times the conventional efficiency. In addition, since the central optical axis of each RGB light is perpendicular to the liquid crystal display panel, there is no problem of color misregistration when viewed obliquely.

(Embodiment 2)
(Constitution)
With reference to FIG. 5, the liquid crystal display device in Embodiment 2 based on this invention is demonstrated. The liquid crystal display device 100 h includes a transmissive liquid crystal display panel 11 h and a backlight device 10. The backlight device 10 is the same as that described in the first embodiment. The liquid crystal display panel 11 h is similar to the liquid crystal display panel 11 described in the first embodiment, but includes a diffraction grating layer 25 instead of the diffraction grating layer 12. The diffraction grating layer 25 includes diffraction grating portions 25R, 25G, and 25B. The diffraction grating portions 25R, 25G, and 25B are arranged in the R, G, and B picture element regions, respectively. The diffraction grating portions 25R, 25G, and 25B are the same as the diffraction grating portions 12R, 12G, and 12B described in the first embodiment in that they have a periodic protrusion structure.

The diffraction grating portions 12R, 12G, and 12B of the first embodiment are different from each other as a result of the grating thickness being determined so as to satisfy the expression (1) according to the wavelength of each color. The grating portions 25R, 25G, and 25B have the same grating thickness and different refractive index differences. The “refractive index difference” is the difference between the refractive index of the material constituting the meat part and the refractive index of the medium filling the gap part, that is, n ₁ −n ₂ in the equation (1). For example, the grating thickness may be constant at 8 μm and the refractive index difference in each diffraction grating portion may be designed as shown in Table 2.

(Action / Effect)
The characteristics shown in FIG. 4 can also be obtained in the diffraction grating layer 25 shown in the present embodiment. Therefore, a phenomenon similar to that described in Embodiment 1 with reference to FIG. 2 occurs. That is, as shown in FIG. 6, the G light out of the light 13 incident on the diffraction grating portion 25G travels straight and is guided to the color filter 6G. Of the light 13 incident on the diffraction grating portion 25G, the R light and the B light are each diffracted in two directions and guided to the color filters 6R and 6B of adjacent picture elements. The color filter 6G receives and transmits three types of light, G light traveling straight from the diffraction grating portion 25G and G light traveling as primary diffraction light from the diffraction grating portions 25R and 25B of the adjacent picture elements. It becomes. Therefore, the light use efficiency can be increased in the present embodiment as in the first embodiment.

(Embodiment 3)
(Production method)
With reference to FIGS. 7 to 13, a method of manufacturing the liquid crystal display device according to the third embodiment of the present invention will be described. This liquid crystal display device manufacturing method is for obtaining the liquid crystal display device described in the first embodiment.

  First, as shown in FIG. 7, a transmissive liquid crystal display panel 21 in which a diffraction grating layer is not yet formed is prepared.

  A plurality of pixels are defined in the liquid crystal display panel 21, and each of the plurality of pixels includes a plurality of picture elements, and the first color element of the plurality of picture elements transmits the first color light. A second color filter that transmits a second color light different from the first color light is disposed in a second picture element different from the first picture element among the plurality of picture elements. .

  The liquid crystal display panel 21 is obtained by bonding transparent substrates 4 and 5 so as to sandwich a liquid crystal layer (not shown), and a color filter layer 6 is disposed inside the transparent substrates 4 and 5. The color filter layer 6 may be formed on any surface of the transparent substrates 4 and 5, or may be formed by the color filter layer 6 alone and inserted between the transparent substrates 4 and 5. Good. In the color filter layer 6, three color filters 6R, 6G, and 6B of RGB are regularly arranged.

  As shown in FIG. 8, a negative photosensitive resin is applied to the surface of the liquid crystal display panel 21 that is to be the backlight device side, that is, the surface of the transparent substrate 5 in this example. Thus, the photosensitive resin layer 31 is formed. When the initial state of the photosensitive resin is liquid, the photosensitive resin layer 31 may be formed by applying by a spin coating method, heating and drying. Alternatively, the photosensitive resin layer 31 may be formed by laminating a dry film type photosensitive resin. The resin used as the material of the photosensitive resin layer 31 may be an ultraviolet curable type or a visible light curable type, but as will be described later, the resin passes through the color filter and the liquid crystal layer in each pixel. Since it is planned to irradiate and sensitize light, it is preferable to use a photosensitive resin having sensitivity around the h-line. “H line” means light having a wavelength of 405 nm. Moreover, you may use positive photosensitive resin instead of negative type.

  Next, curing light that can cure the photosensitive resin layer, transmit the first color filter, and hardly transmit the second color filter is applied to the liquid crystal display panel. The step of partially curing the photosensitive resin layer is performed by sequentially irradiating while changing the incident angle. This process will be described in detail below.

  As shown in FIG. 9, h-line light 32 is irradiated from the substrate 4 side of the liquid crystal display panel 21. Here, the light 32 corresponds to the curing light, the B picture element corresponds to the first picture element, the color filter of the B picture element corresponds to the first color filter, and the color filter of the R picture element or the G picture element Corresponds to the second color filter. If the color filter of the B picture element is regarded as the first color filter, the h-line light 32 corresponds to light that can pass through the first color filter and almost cannot pass through the second color filter. . The reason why the h-ray is selected as the irradiation light is that such a condition is satisfied.

  As shown in FIG. 9, most of the light 32 is absorbed by the color filters of the picture elements other than the B picture element, that is, the color filters 6R and 6G, and conversely, the color filters of the B picture element, that is, the color filters 6B and 6B '. Then most of it is transparent. This transmitted light can be used to pattern the photosensitive resin. When the light 32 transmitted through the color filters 6B, 6B ′ and the like reaches the photosensitive resin layer 31, the photosensitive resin layer 31 is partially exposed and cured. Even the portion of the photosensitive resin layer 31 irradiated with the light 32 is not necessarily cured as a whole when viewed in the thickness direction. Only a certain amount is cured in the thickness direction from the upper surface in FIG. By adjusting the illuminance or irradiation time of the light 32, it is possible to adjust how much thickness is cured from the upper surface of the irradiation region of the light 32 in the photosensitive resin layer 31.

  Irradiation with light 32 as curing light changes the incident angle sequentially so as to reach the region corresponding to each of the plurality of picture elements in the photosensitive resin layer 31, and each time the incident angle is changed, the photosensitivity is changed. The curing light is irradiated while changing the irradiation conditions so that the thickness of the cured portion of the resin layer 31 is different. As a result, the cured portion of the photosensitive resin layer 31 has a periodic step corresponding to each picture element. When development is performed, an uncured portion is removed, and a step structure 34 is formed on the surface of the transparent substrate 5 as shown in FIG. The step structure 34 is thick in the region for forming the diffraction grating portion 12R and thin in the region for forming the diffraction grating portion 12B. The thickness of the region corresponding to each picture element of the step structure 34 at the time of FIG. 10 is set in advance so as to be an optimum thickness after pressing the mold 33 (see FIG. 11) in the subsequent process.

  In this example, the first picture element is assumed to be a B picture element. However, since most photosensitive resins are cured by blue light or ultraviolet light, the first picture element is preferably a B picture element. .

  A mold 33 as shown in FIG. 11 is prepared in advance. The mold 33 is a mold for creating the shape of the diffraction grating layer 12 (see FIG. 1). Accordingly, irregularities are formed on the upper surface of the mold 33 at a pitch equal to the grating pitch to be realized as each of the RGB diffraction grating portions. The groove depth in the unevenness of the mold 33 is constant. The groove depth of the mold 33 should be larger than the deepest groove depth in the diffraction grating layer 12. Such a mold 33 is pressed against the step structure 34 shown in FIG. 10 and heated. That is, as shown in FIG.

  When the grating pitch to be realized as the diffraction grating layer 12 is different between RGB, it is necessary to align the pixel unit with respect to the step structure 34 of the mold 33. In this embodiment, the diffraction grating layer 12 is realized. Since the lattice pitch to be tried is not different among RGB and is common, the uneven pitch of the mold 33 may be equal to the lattice pitch and constant. Therefore, high-precision alignment with the step structure 34 of the mold 33 is not necessary.

  In the present embodiment, since the uneven pitch of the mold 33 is constant, high-precision alignment between the step structure 34 and the mold 33 is unnecessary, but only rotation adjustment needs to be performed. That is, it is necessary to match the direction in which the unevenness on the upper surface of the mold 33 is aligned with the arrangement direction of a plurality of picture elements in one pixel of the liquid crystal display panel. By doing so, the grating arrangement direction of the completed diffraction grating portion and the arrangement direction of the color filters are matched and function correctly.

  When pressure is applied while heating the mold 33 to a temperature higher than the glass transition temperature of the step structure 34, the shape of the mold 33 is transferred to the step structure 34. At this time, since the thickness of the resin of the step structure 34 is different in each region corresponding to each of the RGB picture elements, the resin is unevenly formed in the region to be the diffraction grating portion 12R, and becomes the diffraction grating portion 12B. In the planned region, the resin is unevenly formed. If the mold 33 is peeled after cooling, the liquid crystal display panel 11 having the diffraction grating layer 12 formed on the surface of one transparent substrate 5 is obtained as shown in FIG. As a result, the diffraction grating portions 12R, 12G, and 12B corresponding to the RGB picture elements are formed without requiring highly accurate alignment.

  Hereinafter, according to a known technique, the liquid crystal display device 100 as shown in FIG. 1 is obtained in combination with the backlight device 10.

  When the mold 33 is pressed, the resin in the region that is to be the valley of the diffraction grating in the step structure 34 wraps around the region that is to be the peak, so that the diffraction grating thickness is the step structure 34 before pressing. It may be thicker than the maximum thickness. Therefore, in the step of partially irradiating the photosensitive resin layer 31 by irradiating light, it is preferable to control the thickness of the cured portion of each of the RGB picture element regions by estimating the amount of wraparound.

(Embodiment 4)
(Production method)
A manufacturing method of the liquid crystal display device according to the fourth embodiment of the present invention will be described with reference to FIGS. This method of manufacturing a liquid crystal display device is for obtaining the liquid crystal display device described in the second embodiment.

  First, as shown in FIG. 7, the process up to the preparation of the liquid crystal display panel 21 on which the diffraction grating layer is not yet formed is the same as the manufacturing method of the liquid crystal display device in the third embodiment. As shown in FIG. 14, a negative photosensitive resin is applied on the surface of the substrate 5 on the backlight side of the liquid crystal display panel 11 to form a photosensitive resin layer 35. Next, similarly to the irradiation process described in the third embodiment, the light that cures the photosensitive resin layer 35 and transmits through the color filter of the B picture element is irradiated. This irradiation is performed at an incident angle such that the light reaches the region of the first picture element in the photosensitive resin layer 35 when the light passes through the color filter of the B picture element, that is, the color filter 6B. The first picture element is any one type of picture elements of RGB that are intended to form a diffraction grating portion using the material of the photosensitive resin layer 35. Here, R picture element corresponds. Thus, only the region of the first picture element is cured by the light 32. By removing the uncured photosensitive resin by development, as shown in FIG. 15, the first resin having the first refractive index for the first picture element among R, G, and B picture elements, as shown in FIG. Layer 16R is formed.

  Next, as shown in FIG. 16, a photosensitive resin layer 36 is formed by applying a photosensitive resin different from the material of the photosensitive resin layer 35 so as to cover the first resin layer 16R. As shown in FIG. 17, light that cures the photosensitive resin layer 36 and that passes through the color filter of the B picture element is irradiated. This irradiation is performed at an incident angle such that the light reaches the region of the second picture element in the photosensitive resin layer 36 when the light passes through the color filter of the B picture element. The second picture element is a picture element different from the first picture element in RGB. In the example of FIG. 17, the second picture element is a G picture element. By removing the uncured photosensitive resin by development, the second resin layer 16G (see FIG. 18) having the second refractive index is formed for the second pixel among the three types of RGB.

  Next, as shown in FIG. 18, a third photosensitive resin that is different from the material of the photosensitive resin layer 35 and the material of the photosensitive resin layer 36 is covered with the first resin layer 16R and the second resin layer 16G. Apply. Thus, the photosensitive resin layer 37 is formed. Light that cures the photosensitive resin layer 37 and passes through the color filter of the B picture element is irradiated. This irradiation is performed at an incident angle such that the light reaches the region of the third picture element in the photosensitive resin layer 36 when the light passes through the color filter of the B picture element. The third picture element is a picture element different from the first and second picture elements in RGB. In the present embodiment, the B picture element corresponds. By removing the uncured photosensitive resin by development, as shown in FIG. 19, the third resin layer 16 </ b> B having the third refractive index for the third pixel among the three types of RGB (FIG. 18). Reference) is formed. At this time, as shown in FIG. 19, three types of resin layers 16R, 16G, and 16B having different refractive indexes are arranged for each of the RGB picture elements.

  Thereafter, as shown in FIG. 20, the mold 33 is pressed and heated. The mold 33 may be the same as that described in the third embodiment.

  When the mold 33 is peeled after cooling, a color separation diffraction grating layer 25 is obtained as shown in FIG. That is, the liquid crystal display panel 11h including the diffraction grating layer 25 is obtained. As a result, the diffraction grating portions 25R, 25G, and 25B corresponding to the RGB picture elements are formed without requiring highly accurate alignment.

  Hereinafter, according to a known technique, the liquid crystal display device 100h as shown in FIG. 5 is obtained in combination with the backlight device 10.

  In the liquid crystal display devices in the first and second embodiments, the diffraction grating layers 12 and 25 may be covered with another resin so as to protect them. That is, the protective resin layer 24 may be formed as shown in FIGS. Since the material of the protective resin layer 24 serves as a medium that fills the gap between the diffraction grating layers 12 and 25, the material of the protective resin layer 24 should be selected in consideration of the refractive index. If the protective resin layer 24 is provided, even if dust adheres to the surfaces of the diffraction grating layers 12 and 25, it can be easily wiped off.

  In each of the embodiments described so far, the description has been made on the assumption that one pixel is composed of three types of picture elements. However, when one pixel is composed of two kinds of picture elements, The present invention can also be applied to a case where it is composed of more than one type of picture element.

(Embodiment 5)
(Constitution)
With reference to FIG. 24 and FIG. 25, the liquid crystal display device in Embodiment 5 based on this invention is demonstrated.

  In the liquid crystal display device, a plurality of pixels are defined, and each of the plurality of pixels is different from the first color light in which a first color filter that transmits a first color light is disposed and the first color light. A second picture element having a second color filter that transmits second color light, and a third picture element having a third color filter that transmits third color light different from the first color light and the second color light; A transmissive liquid crystal display panel including a plurality of picture elements including a backlight device that supplies light toward the liquid crystal display panel, and on the surface of the liquid crystal display panel on the backlight device side, The first diffraction grating portion spans the boundary between the second picture element and the third picture element, and the second diffraction grating portion spans the boundary between the first picture element and the third picture element. First to straddle the boundary between the picture element and the second picture element Each of the diffraction grating portions is formed, and the first diffraction grating portion has a property of diffracting the first color light and causing light other than the first color light to travel straight, and the second diffraction grating portion is It has the property of diffracting two-color light and causing light other than the second-color light to travel straight, and the third diffraction grating section has the property of diffracting the third-color light and causing light other than the third-color light to travel straight. And the diffraction grating part which diffracts each light is arrange | positioned by the positional relationship so that the primary diffraction light may inject into the color filter which permeate | transmits each light.

  As shown in FIG. 24, the liquid crystal display device 100 i includes a transmissive liquid crystal display panel 11 i and a backlight device 10. The backlight device 10 is the same as that described in the first embodiment. The liquid crystal display panel 11i is similar to the liquid crystal display panel described in the first embodiment, but includes a diffraction grating layer 52 instead of the diffracted light concept 12 described in the first embodiment. The arrangement position and shape of the diffraction grating portion belonging to the diffraction grating layer 52 are different from those in the diffraction grating layer 12 described in the first embodiment. The diffraction grating layer 52 includes diffraction grating portions 52R, 52G, and 52B. As shown in FIG. 24, the diffraction grating portion 52R is arranged in a region extending across the boundary between the color filter 6G and the color filter 6B. The diffraction grating part 52G is arranged in a region extending over each boundary with the boundary between the color filter 6R 'and the color filter 6R as the center, and the diffraction grating part 52B is arranged in each region. The diffraction grating portions 52R, 52G, and 52B are the same as the diffraction grating portions 12R, 12G, and 12B described in the first embodiment in that they have a periodic protrusion structure.

As shown in FIG. 25, the diffraction grating portions 52R, 52G, and 52B have different grating thicknesses d _R , d _G , and d _B , respectively. In this diffraction grating layer 52, since the grating thickness and the grating depth are equal, the first diffraction grating part, the second diffraction grating part, and the third diffraction grating part have different grating depths.

Referring again to FIG. 24, the grating thickness d _R of the diffraction grating portion 52R diffracts the incident R light and guides it to the color filters 6R, 6R ″ corresponding to the R color, while using light other than the R light. Similarly, the grating thickness d _G of the diffraction grating portion 52G allows the R light and B light to travel straight, while diffracting the G light to diffract the color filter 6G. , 6G 'grating thickness d _B of the. diffraction grating portion 52B that is a thickness such leads to, while linearly moving the R light and the G light, the color filter 6B, 6B diffracts B light' which guides the In order for each diffraction grating portion to satisfy these conditions, for example, the material of the flesh portion of the diffraction grating layer is a resin having a refractive index of 1.6, and the medium that fills the gap is defined as air. In this case, each diffraction grating portion 52R, 52G Grating thickness d _R of 52B, d _G, d _B may be designed in accordance with Table 3 wavelength in each diffraction grating portion of the time -. Showing the relationship between the diffraction efficiency in FIG. 26.

Further, the diffraction grating portion 52R, 52G, the grating pitch P _G of 52B is determined so as to satisfy the following equation (4), and the foregoing equation (3).
tan θ _d = P _P (1 + 0.5) / D (4)
(Action / Effect)
In each of the diffraction grating portions 52R, 52G, and 52B provided in the liquid crystal display device 100i in the present embodiment, the grating pitch can be optimized in accordance with the center wavelengths of the R light, G light, and B light as diffracted light. The diffraction angle of each light can be made the same. Therefore, since the diffracted light can be guided to the target picture element without loss, the light utilization efficiency can be increased.

  The light utilization efficiency in this embodiment will be described. In the conventional liquid crystal display device, since the loss due to the color filter was 2/3, the light use efficiency remained at 1/3 or less. On the other hand, in the present embodiment, the R light incident on the diffraction grating portions 52G and 52B is transmitted without loss, and 50% of the R light is guided to the color filter 6R. Further, part of the R light incident on the diffraction grating portion 52R is also guided to the color filter 6R as diffracted light. Further, part of the R light incident on the diffraction grating portion 52R ′ is also guided to the color filter 6R as diffracted light.

  Accordingly, the color filter 6R is adjacent to the diffraction grating portion 52B, the R light traveling straight from the diffraction grating portions 52G and 52B, and the R light traveling as the primary diffraction light from the diffraction grating portion 52R ′ adjacent to the diffraction grating portion 52G. From the diffraction grating portion 52R, three types of R light traveling as primary diffracted light is incident and transmitted.

  Here, attention is paid to R light, but the same effect can be obtained for G light and B light. When the diffraction grating is designed so that the first-order diffraction efficiency is 30 to 40%, the average first-order diffraction efficiency is considered to be 35%, and the zero-order diffraction efficiency of light of other wavelengths is estimated to be about 90%. The utilization efficiency is 0.9 + 35/100 × 2 = 1.6. That is, the light utilization efficiency as a whole can be increased to 1.6 times that of the prior art. In the first embodiment, since the grating pitch is constant, the light utilization efficiency is implemented considering that the R light and the B light are deviated from the optimum diffraction angle and a loss of about 10 to 20% occurs. It can be estimated that it is equivalent to Form 1.

  Further, in the first embodiment, since the grating pitch is constant, the diffraction angles of the respective lights are slightly different, and there is a problem that a slight color shift remains when viewed obliquely. In this embodiment, the grating pitch may be different for each light, but it is preferable to optimize the grating pitch in accordance with each light. Then, the problem in the first embodiment can be solved.

  In the present embodiment, when the grating pitch of the diffraction grating portion varies depending on the region, the diffraction grating portion may be manufactured using a combination of photolithography and reactive ion etching, or a nanoimprint technique.

(Embodiment 6)
(Constitution)
With reference to FIGS. 27 and 28, a liquid crystal display device according to a sixth embodiment of the present invention will be described. The liquid crystal display device includes a hologram layer, and in the hologram layer, individual hologram portions are arranged in each region obtained by dividing each pixel region into two, respectively, They are arranged in such a positional relationship that the diffracted light is incident on the color filter of the picture element adjacent to the picture element to which the hologram part belongs.

  As shown in FIG. 27, the liquid crystal display device 100j includes a transmissive liquid crystal display panel 11j and a backlight device 10. The backlight device 10 is the same as that described in the first embodiment. The liquid crystal display panel 11j is similar to the liquid crystal display panel 11i described in the fifth embodiment, but further includes a hologram layer 53 in addition to the diffraction grating layer 52. The hologram layer 53 is disposed between the transparent substrate 5 and the diffraction grating layer 52.

  As shown in FIG. 28, the hologram layer 53 includes hologram portions 53R ′, 53R ″, 53G ′, 53G ″, 53B ′, 53B ″. The hologram portion 53R ′ transmits R light that has passed through the diffraction grating portion 52G. Is diffracted and guided to the color filter 6 R. At this time, only the R light is diffracted by the hologram portion 53 R ′, and the light G light and B light of other wavelengths pass through the hologram portion 53 R ′ as they are. Diffraction light is generated in two directions in a rectangular diffraction grating, whereas light can be diffracted in one direction in a hologram, and diffraction efficiency of 90% or more can be obtained by appropriate design. It is.

(Action / Effect)
In the liquid crystal display device 100j according to the present embodiment, the hologram unit 53R ″ diffracts the R light transmitted through the diffraction grating unit 52B and guides it to the color filter 6R. Further, the hologram unit 53G ′ transmits the diffraction grating unit 52B. The G light is diffracted and guided to the color filter 6G, and the hologram portion 53G ″ diffracts the G light transmitted through the diffraction grating portion 52R ′ and guides it to the color filter 6G ′. The hologram section 53B ′ diffracts the B light transmitted through the diffraction grating section 52R and guides it to the color filter 6B. The hologram section 53B ″ diffracts the B light transmitted through the diffraction grating section 52G and guides it to the color filter 6B ′. .

  In the fifth embodiment, since the hologram layer 53 is not provided but only the diffraction grating portion 52 is provided, the light utilization efficiency is about 1.6 times that of the conventional one. However, in the present embodiment, the hologram layer 53 is provided. By providing, the light utilization efficiency can be further improved. When the average diffraction efficiency of the hologram layer 53 is 80%, the light utilization efficiency is 0.9 + 35/100 × 2 + 80/100 = 2.4. That is, the light utilization efficiency as a whole can be increased to 2.4 times the conventional ratio.

  In producing the hologram layer, it is preferable to produce the hologram layer using a contact exposure method in which a master hologram prepared in advance is exposed to light and a photosensitive layer is exposed, and the pattern of the master hologram is transferred to the photosensitive layer. A diffraction grating layer may be formed thereon by the same method as in the fifth embodiment.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the liquid crystal display device in Embodiment 1 based on this invention. It is explanatory drawing of a mode that light advances inside one pixel of the liquid crystal display device in Embodiment 1 based on this invention. It is a partial expanded sectional view of the diffraction grating part contained in the liquid crystal display device in Embodiment 1 based on this invention. It is a graph which shows the relationship between the wavelength and diffraction efficiency in each diffraction grating part contained in the liquid crystal display device in Embodiment 1 based on this invention. It is sectional drawing of the liquid crystal display device in Embodiment 2 based on this invention. It is explanatory drawing of a mode that light advances inside one pixel of the liquid crystal display device in Embodiment 2 based on this invention. It is explanatory drawing of the 1st process of the manufacturing method of the liquid crystal display device in Embodiment 3, 4 based on this invention. It is explanatory drawing of the 2nd process of the manufacturing method of the liquid crystal display device in Embodiment 3 based on this invention. It is explanatory drawing of the 3rd process of the manufacturing method of the liquid crystal display device in Embodiment 3 based on this invention. It is explanatory drawing of the 4th process of the manufacturing method of the liquid crystal display device in Embodiment 3 based on this invention. It is sectional drawing of the type | mold used with the manufacturing method of the liquid crystal display device in Embodiment 3 based on this invention. It is explanatory drawing of the 5th process of the manufacturing method of the liquid crystal display device in Embodiment 3 based on this invention. It is explanatory drawing of the 6th process of the manufacturing method of the liquid crystal display device in Embodiment 3 based on this invention. It is explanatory drawing of the 2nd process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 3rd process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 4th process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 5th process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 6th process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 7th process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 8th process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is explanatory drawing of the 9th process of the manufacturing method of the liquid crystal display device in Embodiment 4 based on this invention. It is sectional drawing of the modification of the liquid crystal display device in Embodiment 1 based on this invention. It is sectional drawing of the modification of the liquid crystal display device in Embodiment 2 based on this invention. It is sectional drawing of the liquid crystal display device in Embodiment 5 based on this invention. It is explanatory drawing of a mode that light advances the inside of 1 pixel of the liquid crystal display device in Embodiment 5 based on this invention, and its vicinity. It is a graph which shows the relationship between the wavelength and diffraction efficiency in each diffraction grating part contained in the liquid crystal display device in Embodiment 5 based on this invention. It is sectional drawing of the liquid crystal display device in Embodiment 6 based on this invention. It is explanatory drawing of a mode that light advances the inside of 1 pixel of the liquid crystal display device in Embodiment 6 based on this invention, and its vicinity. It is explanatory drawing about the function of the multilevel grating structure based on a prior art.

Explanation of symbols

  Light source, 2 light guide plate, 3 prism sheet, 4,5 transparent substrate, 6 color filter layer, 6R, 6G, 6B (for each picture element) color filter, 6B ′, 6R ″ (for adjacent picture element), 10 Backlight device, 11, 11h, 11i, 11j (with diffraction grating layer) Liquid crystal display panel, 12, 25, 52 Diffraction grating layer, 12R, 12G, 12B Diffraction grating section, 13 (emitted from prism sheet) light , 14 (emitted from the diffraction grating), 15 (emitted from the liquid crystal display panel), 16R first resin layer, 16G second resin layer, 16B third resin layer, 21 (no diffraction grating layer) liquid crystal display Panel, 31, 35, 36, 37 Photosensitive resin layer, 32 (h-line) light, 33 type, 34 Stepped structure (of cured photosensitive resin layer), 41 Diffraction grating, 41R 41G, 41B (corresponding to the colors) regions, 46 a color filter, 53 a hologram layer, 100,100h, 100i, 100j liquid crystal display device.

Claims (12)

A plurality of pixels are defined, and each of the plurality of pixels transmits a first color element having a first color filter that transmits the first color light and a second color light different from the first color light. A transmissive liquid crystal display panel including a plurality of picture elements including a second picture element in which a second color filter is disposed;
A backlight device for supplying light toward the liquid crystal display panel,
On the surface of the liquid crystal display panel on the backlight device side, a first diffraction grating portion is formed in the first pixel region, and a second diffraction grating portion is formed in the second pixel region,
The first diffraction grating portion has a property of straightly traveling the first color light and diffracting light other than the first color light,
The second diffraction grating portion has a property of causing the second color light to travel straight and diffracting light other than the second color light,
The liquid crystal display device in which the diffraction grating portion of each picture element is arranged in a positional relationship such that the first-order diffracted light is incident on a color filter of an adjacent picture element.   The liquid crystal display device according to claim 1, wherein the first diffraction grating portion and the second diffraction grating portion are formed of a photosensitive resin.   The liquid crystal display device according to claim 1, wherein the first diffraction grating portion and the second diffraction grating portion have different grating depths.   4. The liquid crystal display device according to claim 1, wherein the first diffraction grating portion and the second diffraction grating portion are formed by a combination of media having different refractive index differences. 5.   The liquid crystal display device according to claim 1, wherein the first diffraction grating part and the second diffraction grating part are covered with a protective resin part. A plurality of pixels are defined, each of the plurality of pixels includes a plurality of picture elements, and a first color filter that transmits a first color light is transmitted through the first picture element of the plurality of picture elements. A transmissive liquid crystal in which a second color filter that is arranged and transmits a second color light different from the first color light is arranged in a second picture element different from the first picture element among the plurality of picture elements. Preparing a display panel;
Forming a photosensitive resin layer on the surface of the liquid crystal display panel that is to be the backlight device side;
Curing light that can cure the photosensitive resin layer, transmit the first color filter, and hardly transmit the second color filter is applied to the liquid crystal display panel. The step of partially curing the photosensitive resin layer by irradiating while sequentially changing the incident angle,
A first diffraction grating portion is formed in the region of the first picture element in the photosensitive resin layer by pressing a diffraction grating mold, and a second diffraction is formed in the region of the second picture element in the photosensitive resin layer. Forming a lattice part. A method for manufacturing a liquid crystal display device.   In the step of partially curing, the incident angle is sequentially changed so that the curing light reaches a region corresponding to each of the plurality of picture elements in the photosensitive resin layer, and the incident angle. A step is formed on the surface of the liquid crystal display panel by irradiating the curing light while changing the irradiation conditions so that the thickness of the portion to be cured of the photosensitive resin layer is different each time when changing 7. A method for producing a liquid crystal display device according to 6. A plurality of pixels are defined, each of the plurality of pixels includes a plurality of picture elements, and a first color filter that transmits a first color light is transmitted through the first picture element of the plurality of picture elements. A transmissive liquid crystal in which a second color filter that is arranged and transmits a second color light different from the first color light is arranged in a second picture element different from the first picture element among the plurality of picture elements. Preparing a display panel;
Forming a photosensitive first resin layer having a first refractive index upon curing on the surface of the liquid crystal display panel that is to be the backlight device side;
The liquid crystal display panel emits first curing light that can cure the first resin layer, transmit the first color filter, and transmit the second color filter. On the other hand, by irradiating the first curing light transmitted through the first color filter at a first incident angle such that the first resin layer reaches a region corresponding to the first pixel in the first resin layer, Partially curing the first resin layer;
Forming a photosensitive second resin layer having a second refractive index different from the first refractive index upon curing on a surface of the liquid crystal display panel that is to be the backlight device side;
The liquid crystal display panel emits second curing light that can cure the second resin layer, transmit the first color filter, and transmit substantially the second color filter. In contrast, by irradiating the second curing light transmitted through the first color filter at a second incident angle such that the second resin light reaches a region corresponding to the second picture element in the second resin layer, And a step of partially curing the second resin layer.   The method of manufacturing a liquid crystal display device according to claim 6, wherein the plurality of picture elements include a red picture element, a green picture element, and a blue picture element, and the first picture element is the blue picture element. . A plurality of pixels are defined, and each of the plurality of pixels transmits a first color element having a first color filter that transmits the first color light and a second color light different from the first color light. A plurality of picture elements including a second picture element in which a second color filter is arranged and a third picture element in which a third color filter that transmits a third color light different from the first color light and the second color light is arranged. A transmissive liquid crystal display panel including
A backlight device for supplying light toward the liquid crystal display panel,
On the surface of the liquid crystal display panel on the backlight device side, a first diffraction grating portion extends across the boundary between the second picture element and the third picture element, and the first picture element and the third picture element. A second diffraction grating portion is formed so as to straddle a boundary between the first and second pixel elements, and a third diffraction grating portion is formed so as to straddle a boundary between the first and second picture elements,
The first diffraction grating portion has a property of diffracting the first color light and causing light other than the first color light to go straight.
The second diffraction grating portion has a property of diffracting the second color light and causing light other than the second color light to go straight.
The third diffraction grating portion has a property of diffracting the third color light and causing light other than the third color light to travel straight.
The diffraction grating part that diffracts each light is a liquid crystal display device that is arranged in a positional relationship such that the first-order diffracted light is incident on a color filter that transmits each light.   The liquid crystal display device according to claim 10, wherein the first diffraction grating part, the second diffraction grating part, and the third diffraction grating part have different grating depths. With a hologram layer,
In the hologram layer, an individual hologram part is arranged in each region obtained by dividing each pixel region into two parts,
12. The liquid crystal display device according to claim 10, wherein each of the hologram parts is arranged in a positional relationship such that diffracted light is incident on a color filter of a picture element adjacent to the picture element to which the hologram part belongs.

Images