JP3823669B2 - Liquid crystal device and electronic apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal device and an electronic device including the same, and more particularly to a liquid crystal device having a color filter layer and an electronic device including the same.
[0002]
[Prior art]
For example, as shown in FIG. 14, the liquid crystal device 500 includes a liquid crystal 160 disposed between a pair of substrates 120 and 140 facing each other, and modulates light passing through the liquid crystal according to the alignment state of the liquid crystal 160 to display an image. Is to do. Transparent electrodes 240 a made of indium tin oxide (hereinafter referred to as “ITO”) or the like are arranged in a matrix on the opposite surface of the substrate 120, and blue, green, and red colors are formed on the other substrate 140. Filter layers 200a, 200b, and 200c are formed in a matrix at positions corresponding to the transparent electrodes 240a, and a protective layer 220 is formed on each color filter layer. A strip-shaped transparent electrode 240b extending in the lateral direction is formed on the protective layer 220. The incident light from the substrate 120 is colored blue, green, or red (lights P ₁ , P ₂ , P ₃ ) by the color filter layers 200a, 200b, and 200c, respectively, and emitted from the substrate 140 side. The combined light P of these P ₁ , P ₂ , and P ₃ is recognized as an image.
[0003]
[Problems to be solved by the invention]
However, in the case of the liquid crystal device 500 described above, there is a problem that the color balance of the image (synthetic light P) is lowered. Here, the color balance (white balance) is light obtained by combining the light P ₁ , P ₂ , and P ₃ transmitted through the color filter layers 200a, 200b, and 200c with the same intensity when the liquid crystal device displays white. P indicates the color tone, and the closer to white, the better the display color characteristics of the actual image. The color balance is usually represented by chromaticity x and y of the CIE 1931 color system, and the closer this value is to the chromaticity value of the C light source, the better the color balance.
[0004]
By the way, in the liquid crystal device 500, the transparent electrodes 240a and 240b and the protective layer 220, which are constituent elements thereof, may have a color such as yellow. That is, the incident light passes through the transparent electrode 240a, the liquid crystal 160, the transparent electrode 240b, the protective layer 220, and the color filter layer 200a (200b, 200c) through the transparent electrode 240a, the color filter layer 200a (200b, 200c), and is transparent. Light of a specific wavelength is absorbed by the electrode and the protective layer, and as a result, the color balance of the image is lowered. In this case, the display color tone of the image becomes yellow under the influence of the color of the transparent electrode or the like.
[0005]
In particular, in the case of a reflective display type liquid crystal device, incident light passes through the transparent electrodes 240a and 240b and the protective layer 220, and then is reflected by the reflective layer and again passes through the transparent electrode and the protective layer. The degree of light absorption by the protective layer becomes stronger, and accordingly, the color balance of the image is significantly reduced.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems in a liquid crystal device, and to provide a liquid crystal device with improved color balance of an image and an electronic apparatus using the same.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a color filter substrate of the present invention is disposed so as to face at least a color filter substrate on which each color filter layer of blue, green and red is formed, and the color filter substrate via a liquid crystal. A liquid crystal device comprising a counter substrate,
A protective layer for protecting the color filter and a first transparent electrode are laminated in this order on the color filter substrate, and a second transparent electrode is formed on the liquid crystal side of the counter substrate, chromaticity x _oth of light transmitting therethrough at least the protective layer and the first transparent electrode and the second transparent electrode, y _oth is, C light source chromaticity substantially identical to chromaticity x _set, y _set When the transmitted light is yellowish, the light transmitted through each of the color filter layers so that the chromaticity when the liquid crystal device displays white is closer to the x _set and y _set The chromaticities x _CF and y _CF of the synthesized light are expressed by the following formulas: x _CF = 2x _set −x _oth , y _CF = 2y _set −y _oth
(However, the chromaticity x, y is shown in the CIE 1931 color system, and the chromaticity in the case of using a C light source) is shifted to the blue side from the x _set and y _set and adjusted. And
[0008]
According to such a configuration, the chromaticity of the light transmitted through the components other than the color filter layers in the liquid crystal device is shifted from the chromaticity substantially the same as the chromaticity of the C light source and has a predetermined color tone. Even if the image is tinged, the chromaticity of each color filter layer is adjusted in advance so as to cancel the shift, so that the color balance can be improved by making the image the same as the design chromaticity.
[0011]
The liquid crystal device is a transflective liquid crystal device, and the constituent element includes a reflective layer, and the chromaticity x _oth and y _oth exclude the reflective layer among the constituent elements. The chromaticity x _CF and y _CF are defined by the chromaticity of the combined light of the light that passes through each of the color filter layers twice. It is characterized by.
[0012]
Furthermore, it is preferable that the x _CF and y _CF are adjusted by increasing the film thickness of each color filter layer by the same ratio.
[0013]
An electronic apparatus according to the present invention includes the liquid crystal device.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a liquid crystal device according to the present invention will be described with reference to FIGS. In addition, the liquid crystal device in the present invention means a device including at least a color filter substrate provided with a color filter layer described later and a counter substrate disposed so as to face the liquid crystal. There are no particular restrictions on the elements for controlling the electrodes and pixel electrodes, and there is no particular limitation. A passive matrix liquid crystal device, and an active matrix liquid crystal device including a TFT (thin film transistor) element or a TFD (Thin Film Diode) element as a switching element. Applicable to.
[0015]
As shown in FIG. 1, the color filter substrate 8 is disposed to face the counter substrate 38 at a predetermined interval, and liquid crystal is interposed between the substrates 8 and 38 to constitute the liquid crystal device 50 as a whole. . In this embodiment, the liquid crystal device 50 is an active matrix type TFD (Thin Film Diode) liquid crystal device. On the counter substrate 38 side, which is an element substrate, a plurality of pixel electrodes made of a transparent electrode such as ITO (Indium Tin Oxide) in a matrix on the surface (lower surface) of the substrate 30 made of quartz or the like facing the color filter substrate 8. 32 and a TFD element 36 for controlling a voltage applied to the pixel electrode 32 is provided. The TFD 36 is connected to the scanning line 34 for each column, and controls the display operation by switching the liquid crystal to a display state, a non-display state, or an intermediate state based on a scanning signal and a signal applied to a data line 22 described later. It is carried out. Since the entire structure of the liquid crystal device 50 and the detailed operation of image display are the same as those of the conventional one, the description thereof is omitted.
[0016]
The color filter substrate 8 is configured as follows. First, a reflective layer 4 made of a metal film is formed over the entire surface of a substrate 2 made of quartz or the like, and a blue color filter is formed on the reflective layer 4 at a position facing the pixel electrode 32 of the counter substrate 38 in a matrix. A layer (illustrated “B”) 10, a green color filter layer (illustrated “G”) 12, and a red color filter layer (illustrated “R”) 14 are formed, and these constitute the three primary colors of light. . Here, the color filter layers 10, 12, and 14 are spaced apart from each other, and a light shielding layer 6 described later corresponds to a non-image display region (a region where the pixel electrode 32 is not formed) therebetween. Is formed. Further, a protective layer (not shown) is formed on each of the color filter layers 10, 12, and 14, and a plurality of strip-like ITOs are formed on the protective layer so as to intersect the extending direction of the scanning lines 34. Data lines 22 are formed.
[0017]
Here, as the metal film to be the reflective layer 4, for example, a material having high reflectance such as aluminum, silver, or an alloy thereof can be used. It can be produced by a dispersion method. And since each color filter layer comprises three primary colors (R, G, B) of light, it is preferable that R, G, B are alternately arranged in any direction. For example, in this embodiment, R, G, and B are alternately arranged from the left to the right of the color filter substrate 8, but R, G, and B are alternately arranged in a direction perpendicular thereto. May be.
[0018]
Note that a rectangular window 4d is formed in the reflective layer 4 in the vicinity of the center of each color filter layer 10, 12, 14 and the irradiation light from the backlight 70 disposed on the outer surface side of the color filter substrate 8 is opposed to the reflective layer 4. The light is transmitted to the substrate 38 side. That is, the liquid crystal device 50 performs reflective display by the base reflective layer 4 at the peripheral portions of the color filter layers 10, 12, and 14, and performs transmissive display by the window 4d at the central portion (semi-transmissive). Reflective type). By doing so, it combines the advantages of a reflective display type that is advantageous in terms of power consumption and a transmissive display type that can display without being affected by the presence or absence of ambient light, and can switch the display method according to the ambient light Thus, clear display is possible while reducing power consumption. Furthermore, by adjusting the aperture ratio of the window 4d, it is possible to appropriately design a display that emphasizes use during reflection or a display that emphasizes use during transmission.
[0019]
The cross-sectional structure of the liquid crystal device 50 taken along the line AA ′ in FIG. 1 is as shown in FIG.
[0020]
In this figure, the light-shielding layer 6 is formed by placing the blue color filter layer 10 as the lowermost layer and sequentially stacking the other color filter layers 12 and 14 thereon. The light incident on the light shielding layer 6 from the counter substrate 38 through the liquid crystal 40 is absorbed by each of the color filter layers 10, 12, and 14, so that the light shielding layer 6 functions as a black matrix (illustrated region D ₃ ). To do. On the other hand, the area including the pixel electrode 32 is a display area (illustrated area D ₁ ), of which the area including the window 4 d is a transmissive display area (illustrated area D ₂ ), and the rest is a reflective display area. Yes. A protective layer 20 made of, for example, an acrylic resin is formed on each color filter layer 10, 12, 14 and the light shielding layer 6, and a data line 22 is formed on the protective layer 20. .
[0021]
Then, image display (during reflection) is performed as shown in FIG. First, light incident on the substrate 30 from the outside of the counter substrate 38 is the substrate 30, the pixel electrode 32, an alignment film (not shown), a liquid crystal 40, an alignment film, a data line (counter electrode) 22, a protective layer 20, and a color filter layer. 10 (or 12, 14) are transmitted in this order and reflected by the reflective layer 4, then emitted in the direction opposite to the incident direction, that is, emitted from the color filter layer 10 (12, 14) toward the substrate 30 and displayed as an image. . In this way, the incident light is colored by any one of the color filter layers 10, 12, and 14 in the process of passing through the optical path E returning from the substrate 30 through the reflective layer 4 to the substrate 30, and the colored light L ₁ , L ₂ and L ₃ are combined to form an image L. In this case, if the intensities of the lights L ₁ , L ₂ and L ₃ are the same, the image L is displayed in white.
[0022]
By the way, normally, when designing a liquid crystal device, a component 60 (for example, an optical element such as a retardation film or a polarizing film, a substrate 30, a pixel electrode 32, a substrate) in the pixel region of the liquid crystal device 50 excluding a color filter layer. It is assumed that the alignment film on the 30th side, the liquid crystal 40, the alignment film on the substrate 2 side, the data line (counter electrode) 22, the protective layer 20, the reflective layer 4, etc.) do not absorb light of a specific wavelength. In order to make the color balance of the image the same as that of the C light source, the color tone of the combined light transmitted through each of the color filter layers 10, 12, and 14 is adjusted to match the C light source. However, in practice, the component 60 often has a predetermined color. This will be described with reference to FIGS. 4 to 6 show the spectral characteristics of the transmitted light and the reflected light when the protective layer 20 and the transparent electrodes 32 and 22 that are part of the component 60 are respectively irradiated with the C light source, and FIG. The position of the reflected light on the xy chromaticity diagram is shown. The chromaticities x and y in the present invention are represented by the CIE 1931 color system and refer to chromaticities when a C light source is used.
[0023]
In FIG. 4, when the spectral characteristic of the light transmitted through the protective layer 20 is seen, blue light around 400 nm is absorbed, and thus the transmitted light is yellowish. On the other hand, in the case of reflected light, light transmitted through the protective layer 20 is reflected by the reflective layer and is transmitted again through this layer (corresponding to twice transmitted light), so that it absorbs blue light compared to normal transmitted light. The degree of is strong. Similarly, in FIG. 5, when the spectral characteristics of the light transmitted through the transparent electrodes 32 and 22 are observed, absorption is observed over all wavelengths, but blue absorption is particularly remarkable. That is, the transparent electrodes 32 and 22 are more yellowish than the protective layer 20. Further, as shown in FIG. 6, the blue absorption degree becomes more conspicuous in the light transmitted through both the protective layer 20 and the transparent electrodes 32 and 22.
[0024]
When these relationships are shown in FIG. 7, the chromaticity of the light transmitted through the protective layer 20 and the transparent electrodes 32 and 22 is shifted in the upper right direction (yellow side) compared to the chromaticity of the C light source, and the shift amount is protected. It is the largest when light passes through both the layer 20 and the transparent electrodes 32 and 22. Therefore, in the present invention, as shown in FIG. 8, in order to cancel the coloring of the protective layer 20 and the transparent electrodes 32 and 22 (hereinafter collectively referred to as “component 60”), each color filter layer is previously provided. The chromaticity of 10, 12, 14 is adjusted.
[0025]
In this figure, the chromaticity P (x _oth , y _oth ) of the light transmitted through any one of the components 60 is located in the yellow region as described above. When no chromaticity adjustment of the color filter layers 10, 12, and 14 is performed, the chromaticity R ′ when the image is actually displayed in white is also located in the yellow region. On the other hand, the chromaticity Q (x _CF , y _CF ) of the combined light transmitted through the color filter layers 10, 12, 14 is previously set in each color filter layer so that it is located on the complementary color side (blue) of the point P If the chromaticity is adjusted, the influence of coloring of the component 60 can be canceled.
[0026]
Specifically, an R described later is positioned at the midpoint between P and Q, that is,
x _CF = 2x _set −x _oth , y _CF = 2y _set −y _oth (1)
The chromaticity of each color filter layer is adjusted to satisfy the above condition. In this way, the chromaticity R ′ can be shifted to the blue side by a certain amount so as to be close to the same (white) as the design chromaticity R. Here, the design chromaticity x _set and y _set are design values of chromaticity when the liquid crystal device 50 displays white, and ideally match the chromaticity of the C light source. Actually, it is difficult to completely match the chromaticity R ′ when displaying white with the design chromaticity R. Therefore, in the present invention, “substantially the same” is included, including the case where the difference between R ′ and R is within the design chromaticity R ± 0.01.
[0027]
Next, a method for actually adjusting the chromaticity of each color filter layer will be described with reference to FIGS.
[0028]
In FIG. 9, Q _i indicates the chromaticity of light reflected (transmitted twice) in each color filter layer 10, 12, and 14 (where i is one of blue, green, and red color filter layers). , B (blue), G (green), and R (red)), and the chromaticities x _CF and y _CF of the combined light of these transmitted lights are indicated by a point Q. And as the film thickness of each color filter layer 10, 12, 14 increases, each Q _i shifts to the outside of the xy chromaticity diagram (in the direction in which the saturation improves), but the film thickness of each color filter layer It can be seen that the position of the point Q does not change if is increased at the same rate. The chromaticities x _CF and y _CF of the synthesized light are obtained by obtaining the tristimulus values X _i , Y _i and Z _i of the light reflected by each color filter layer (light transmitted twice) and forming the following equations: can get.
[0029]
_{x CF = (X B + X} G + X R) / {(X B + Y B + Z B) + (X G + Y G + Z G) + (X R + Y R + Z R)} (2)
_{y CF = (Y B + Y} G + Y R) / {(X B + Y B + Z B) + (X G + Y G + Z G) + (X R + Y R + Z R)} (3)
On the contrary, if the position of the point Q is changed by increasing or decreasing the thickness of each color filter layer at a different rate, the chromaticity of the synthesized light can be adjusted. That is, as shown in FIG. 10, normally, the chromaticity of each of the color filter layers 10, 12, and 14 is adjusted so that the chromaticity Q is close to the chromaticity of the C light source. The film thickness of 10 is increased and the chromaticity Q ′ _B is moved to the outside of the chromaticity diagram (the saturation is increased), while the film thicknesses of the green and red color filter layers 12 and 14 are respectively changed. Adjustment is performed to reduce the chromaticity Q ′ _G and Q ′ _R to the inside of the chromaticity diagram (decrease the saturation). Then, the chromaticity Q ′ of the combined light shifts to the lower left side of the figure, that is, the blue side that is the complementary color of yellow of the component 60. Therefore, when the image is displayed, the coloring of the component 60 can be canceled. Improves the color balance.
[0030]
In the above-described embodiment, the chromaticity is adjusted by changing the film thickness of each of the color filter layers 10, 12, and 14. For example, the content ratio (concentration) of the pigment (pigment) included in the color filter layer ) Can be changed to adjust the chromaticity. Further, it is not necessary to adjust the chromaticity of the color filter layers of all colors, and only the chromaticity of the color filter layer of any one color may be adjusted. Further, when the component is yellowish, the color filter layer may be adjusted to the blue side. However, the present invention is not limited to this. For example, when the component is greenish, the color filter layer The layer may be adjusted to the red side.
[0031]
In the actual production of the liquid crystal device, for example, the display image at that time for each component of the portion of the pair of substrates that is disposed on each of the pair of substrates except for the color filter layer and where the liquid crystal drive electrodes of the pair of substrates overlap. chromaticity x _oth, leave measured y _oth, the degree of chromaticity adjustment of the color filter layer thereto was calculated according to equation (1), accordingly, manufacturing the liquid crystal device in which the chromaticity adjustment of the color filter layer do it. When defining the chromaticities x _oth and y _oth , it is not always necessary to target all the components of the liquid crystal device, and it is not necessary to consider the components that absorb little light. .
[0032]
In the above-described embodiments, the case of the reflective display type has been described. However, in the case of performing transmissive display, x _oth , y is the chromaticity when incident light is transmitted once through each component of the liquid crystal device. _oth , x _CF and y _CF may be defined.
[0033]
In addition to these, the present invention can be applied not only to the above-described active matrix type liquid crystal device but also to a passive matrix type liquid crystal device such as STN or a segment type liquid crystal device. Further, at least one of the electrodes disposed on the opposing substrates may be a transparent electrode, and the other electrode may of course be formed of a reflective layer made of a metal film.
[0034]
[Electronics]
Hereinafter, specific examples of the electronic apparatus including the liquid crystal device of the present invention will be described.
[0035]
FIG. 11 is a perspective view showing an example of a mobile phone.
[0036]
In this figure, reference numeral 1000 denotes a mobile phone body, and reference numeral 1001 denotes a liquid crystal display unit using the above electro-optical device.
[0037]
FIG. 12 is a perspective view showing an example of a wristwatch type electronic apparatus.
[0038]
In this figure, reference numeral 1100 denotes a watch body, and reference numeral 1101 denotes a liquid crystal display unit using the electro-optical device.
[0039]
FIG. 13 is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer.
[0040]
In this figure, reference numeral 1200 denotes an information processing apparatus, reference numeral 1202 denotes an input unit such as a keyboard, reference numeral 1204 denotes an information processing apparatus body, and reference numeral 1206 denotes a liquid crystal display unit using the above electro-optical device.
[0041]
Since the electronic devices shown in FIGS. 11 to 13 include a liquid crystal display unit using the above-described liquid crystal device, an electronic device with excellent color balance can be realized.
[0042]
【The invention's effect】
As is apparent from the above description, according to the present invention, the chromaticity of the light transmitted through the components other than the color filter layers in the liquid crystal device is shifted from the design chromaticity and has a predetermined color. However, since the chromaticity of each color filter layer is adjusted in advance so as to cancel out the shift, the color balance of an image obtained when both of the above components and each color filter layer are transmitted can be improved. .
[0043]
In particular, in the case of a reflective display type or a reflective / transmissive display type liquid crystal device, the coloring of the constituent elements becomes remarkable, so that the effect of the present invention is further enhanced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a liquid crystal device of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG.
FIG. 3 is a cross-sectional view showing light transmitted through a liquid crystal device.
FIG. 4 is a graph showing spectral characteristics of light transmitted or reflected by a protective layer that constitutes a component of a liquid crystal device.
FIG. 5 is a graph showing spectral characteristics of light that is transmitted or reflected through a transparent electrode that is a constituent element of a liquid crystal device.
FIG. 6 is a graph showing spectral characteristics of light that is transmitted or reflected by a protective layer and a transparent electrode that are constituent elements of a liquid crystal device.
FIG. 7 is a diagram illustrating a position on an xy chromaticity diagram of light transmitted through a component of a liquid crystal device.
FIG. 8 is an xy chromaticity diagram illustrating a mode in which the chromaticity of the color filter layer is adjusted with respect to the chromaticity of the component.
FIG. 9 is an xy chromaticity diagram showing a relationship between chromaticity and film thickness of each color filter layer.
FIG. 10 is an xy chromaticity diagram showing an aspect of adjusting the chromaticity of light transmitted through each color filter layer.
FIG. 11 is a perspective view illustrating an example of an electronic apparatus including the liquid crystal device according to the invention.
FIG. 12 is a perspective view showing another example of the electronic apparatus.
FIG. 13 is a perspective view showing still another example of the electronic apparatus.
FIG. 14 is a partial cross-sectional view showing a conventional liquid crystal device.
[Explanation of symbols]
2, 30 Substrate 4, 4A Reflective layer 8, 8A Color filter substrate 10, 10A Blue color filter layer 12, 12A Green color filter layer 14, 14A Red color filter layer 38, 38A Counter substrate 40 Liquid crystal 50, 50A Liquid crystal Device 60 component E (of the liquid crystal device) optical path P (of the liquid crystal device) chromaticity Q of the light transmitted through the component Q chromaticity R of the combined light of the light transmitted through the color filter layer design chromaticity R (of the liquid crystal device) '' Chromaticity when displaying white (liquid crystal device)

Claims (4)

A liquid crystal device comprising: a color filter substrate on which at least blue, green and red color filter layers are formed; and a counter substrate disposed opposite to the color filter substrate via liquid crystal,
On the color filter substrate, a protective layer for protecting the color filter and a first transparent electrode are laminated in this order,
A second transparent electrode is formed on the liquid crystal side of the counter substrate;
The chromaticity x _oth , y _{oth of} the light transmitted at least through the protective layer, the first transparent electrode, and the second transparent electrode is substantially the same as the chromaticity of the C light source x _set , y _When deviating from the _set and the transmitted light is yellowish,
The chromaticities x _CF and y _CF of light obtained by synthesizing light transmitted through the respective color filter layers so that the chromaticity when the liquid crystal device displays white is close to the x _set and y _set are expressed by the following equations:
x _CF = 2x _set −x _oth , y _CF = 2y _set −y _oth
(However, the chromaticity x, y is shown in the CIE 1931 color system, and the chromaticity in the case of using a C light source) is shifted to the blue side from the x _set and y _set and adjusted. A liquid crystal device. The liquid crystal device is a transflective liquid crystal device, and the component includes a reflective layer,
The chromaticities x _oth and y _oth are defined by the chromaticity of light that is transmitted twice through the components excluding the reflective layer among the components,
2. The liquid crystal device according to claim 1, wherein the chromaticity x _CF and y _CF are defined by chromaticity of combined light of light transmitted through each color filter layer twice. 3. The liquid crystal device according to claim 1, wherein the x _CF and y _CF are adjusted by increasing the thickness of each color filter layer by the same ratio. 4.   An electronic apparatus comprising the liquid crystal device according to claim 1.

Images