JP3752915B2 - Reflective liquid crystal display device and electronic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reflective liquid crystal display device including a pair of substrates provided with a liquid crystal layer interposed therebetween, and an electronic device including the same, and more particularly, an anodic oxide film is formed on a metal substrate or a pixel electrode and colored. The present invention relates to a structure that also serves as a color filter.
[0002]
[Prior art]
In various electronic devices such as notebook personal computers, portable game machines, and electronic notebooks, liquid crystal display devices with low power consumption are often used as display units. Particularly in recent years, with the diversification of display contents, the demand for liquid crystal display devices capable of color display is increasing. In addition, in order to increase the battery driving time of the electronic device, a reflective color liquid crystal display device that does not require a backlight device has been developed.
[0003]
FIG. 10 is an enlarged schematic sectional view showing a main part of an example of a conventional reflective color liquid crystal display device. The reflective color liquid crystal display device shown in FIG. 10 has a structure referred to as an inner surface scattering type, and includes a pair of glass substrates 100 and 101 and a liquid crystal layer 102 sandwiched between the glass substrates 100 and 101. On the surface on the liquid crystal layer 102 side, a pixel electrode 107 made of an Al thin film or the like that also serves as a reflector is formed with a concavo-convex portion for irregularly reflecting light on the surface. Note that a sealing material is actually formed between the peripheral portions of the glass substrates 100 and 101 so as to be sandwiched between the glass substrates 100 and 101 to seal the liquid crystal layer 102. In FIG. Is omitted.
[0004]
Here, a color filter 104 is formed on the surface of the glass substrate 101 on the light incident side on the liquid crystal layer 102 side, and a polarizing plate 106 is provided on the upper surface side of the glass substrate 101. In such an internal scattering plate type liquid crystal display device, incident light L1 is diffusely reflected on the surface of the pixel electrode 107 after passing through the polarizing plate 106, the glass substrate 101, the color filter 104, and the liquid crystal layer 102. After the polarization is changed depending on the state, the reflected light passes through the color filter 104 and the glass substrate 101, and is transmitted or not transmitted by the polarization state of the reflected light by the polarizing plate 106. In the case of transmission, the color of the color filter 104 In the case of non-transmission, the color filter 104 is visually recognized as a color liquid crystal display by being incident on the observer's naked eye E as scattered light L2 in a state where the color of the color filter 104 is not directly visible.
[0005]
[Problems to be solved by the invention]
In this type of conventional reflective color liquid crystal display device, the substrates 100 and 101 for sandwiching the liquid crystal layer 102 are generally composed of glass substrates. In recent years, portable telephone devices or portable information terminal devices to which this type of reflective color liquid crystal display device is applied are required to be further reduced in size, weight, and thickness. There is a demand for further weight reduction of the type of color liquid crystal display device itself.
[0006]
Accordingly, when examining the weight of this type of conventional reflective color liquid crystal display device, the weight of the glass substrates 100 and 101, which occupy the largest volume, occupies most of the weight. In order to reduce the weight, it seems most effective if the glass substrate is made thinner. However, the current glass substrate is sufficiently thinned to have a thickness of about 0.3 mm, and in view of the strength of the glass itself, it is difficult to reduce the thickness further.
[0007]
Further, unlike the structure shown in FIG. 10, a light-scattering / reflecting layer 108 is provided on the back side of the glass substrate 100 as shown by a two-dot chain line, and the pixel electrode 107 is a flat transparent electrode with no unevenness. A structure composed of is also known.
[0008]
If it is this structure, a light-scattering reflection surface can be comprised by sticking the ready-made light-scattering reflection layer 108 manufactured by another process to the back surface side of the glass substrate 100, and it forms in the upper surface side of the glass substrate 100. However, since the light is reflected on the back side of the glass substrate 100, the reflection efficiency is inferior and it is difficult to obtain a bright display as a reflective liquid crystal display device.
[0009]
Further, in this type of conventional reflection type liquid crystal display device, it is common to provide a color filter 104 on the surface of the light incident side glass substrate 101 on the liquid crystal layer 102 side for color display. If 104 is separately formed on the glass substrate 101 side, a separate process for forming the color filter 104 is required, which complicates the manufacturing process and increases the distance from the surface of the pixel electrode 107 serving as a light reflecting surface. There is a problem that color misregistration is likely to occur depending on the incident angle of incident light.
[0010]
The present invention has been made in view of the above-described problems, and one of the substrates sandwiching the liquid crystal layer is used as a metal substrate to reduce the weight, thickness, and size of the entire device, and anodization formed on the metal substrate. An object is to provide a reflective liquid crystal display device in which a film is colored and a metal substrate is provided with a color display function. In addition, the color display function formed on the metal substrate can be displayed for the three primary colors by corresponding to each pixel electrode, so that the color filter function on the metal substrate is added to the conventional color filter on the counter substrate side. One object is to provide an omitted reflective liquid crystal display device.
[0011]
Further, the present invention provides a color filter on the counter substrate side which has been conventionally required by providing a color filter function to the metal electrode itself as a metal electrode having a colored anodic oxide film on at least the liquid crystal layer side surface of the pixel electrode. Of a reflective liquid crystal display device that eliminates the color shift of reflected light as a structure in which a color filter can be disposed immediately above the light reflecting surface by providing a color filter function on the surface side of the light reflective pixel electrode. One of the purposes is provision.
[0012]
A further object of the present invention is to provide an electronic apparatus provided with the reflective liquid crystal display device having the above-described excellent features.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a reflective liquid crystal display device of the present invention is a reflective liquid crystal display device, wherein a liquid crystal layer is sandwiched between a metal substrate and a transparent substrate disposed to face the metal substrate. A reflection surface having a concavo-convex portion is formed on the surface of the metal substrate on the liquid crystal layer side to form a light reflection diffusion surface of the metal substrate, and an insulating layer is coated on the light reflection diffusion surface of the metal substrate. A pixel electrode made of metal is formed on the insulating layer, and a reflective surface having a concavo-convex portion is formed on a surface of the pixel electrode on the liquid crystal side to form a light diffusing reflective surface of the pixel electrode, In addition, an anodic oxide film is formed on the light diffusing and reflecting surface, and the anodic oxide film is colored, and the light reflecting and diffusing surface of the metal substrate is also formed between the pixel electrodes.
[0015]
Furthermore, if a metal substrate is used instead of the conventional glass substrate used in the reflective liquid crystal display device, it is possible to make the metal substrate thinner than the glass substrate even if it has the same strength as the glass substrate. Therefore, it can be made thinner, lighter, and smaller than the conventional structure using a glass substrate. Next, since the surface of the metal substrate on the liquid crystal side is used as a direct reflection surface, the reflection efficiency is good and a bright high-quality display can be obtained.
[0017]
Since the anodized film on the pixel electrode is colored, it can be colored with the anodized film directly above the pixel electrode that reflects light, and the light transmission state of the liquid crystal layer by the pixel electrode and the opposite electrode Is controlled, the color of the anodized film immediately above the pixel electrode can be displayed in color.
[0023]
Since the anodic oxide film on the metal substrate corresponding to the pixel electrode formation position or the anodic oxide film on the pixel electrode also serves as a color filter, the color filter conventionally provided on the counter substrate side can be omitted. In addition, the metal substrate or pixel electrode has a light reflecting surface, and a colored anodic oxide film is formed on the light reflecting surface, so that it is more reflective than the conventional structure in which a color filter is provided on the opposite substrate. The distance between the surface and the colored anodic oxide film is reduced, and a bright display with little color shift can be obtained.
[0024]
In the reflective liquid crystal display device of the present invention, at least the surface of the metal substrate on the liquid crystal layer side is made of at least one of Al, Mg, Ti, and Be or an alloy mainly composed of each of these metal elements. It is possible to adopt a structure in which the insulating layer covered with is made of an anodic oxide film of these metals or alloys. With these metal anodic oxide films, a uniform insulating layer can be formed on the metal substrate with good adhesion and insulation.
[0026]
The electronic apparatus of the present invention comprises the above-described various reflective liquid crystal display devices as a display unit. If the electronic device includes the above-described excellent reflective liquid crystal display device, it is possible to promote reduction in thickness, weight, and size, and to obtain a display with high display quality. In addition, if the electronic device includes the excellent reflective liquid crystal display device described above, a structure in which the configuration of the color filter portion is simplified can be provided.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0028]
(First embodiment of reflective liquid crystal display device)
A liquid crystal panel according to a first embodiment of a reflective liquid crystal display device according to the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view showing a first embodiment in which the present invention is applied to a reflective TFD type (Thin Film Diode type) liquid crystal panel, and FIG. 2 is a sectional view of the first embodiment. 3 is an enlarged cross-sectional view of the pixel electrode portion of the first embodiment, and FIG. 4 is an enlarged cross-sectional view of the switching element portion of the first embodiment.
[0029]
A reflective liquid crystal display device as a final product is configured by mounting auxiliary elements such as a liquid crystal driving IC and a support on the liquid crystal panel 10 of this embodiment.
[0030]
The liquid crystal panel 10 of this embodiment includes a pair of a transparent substrate 13 and a metal substrate 14 having a substantially rectangular shape in a plan view and a pair of rectangular shapes in a plan view that are attached to face each other via an annular sealing material 12. The liquid crystal layer 15 sandwiched between the sealing materials 12 and the polarizing plate 16 provided on the upper surface side (observer side) of one transparent substrate 13 are mainly configured. Of the substrates 13 and 14, the transparent substrate 13 is made of transparent glass and is a front side substrate provided facing the observer side, and the metal substrate 14 is an opaque metal provided on the opposite side, in other words, on the back side. Is a thin substrate. In this embodiment, only one polarizing plate 16 is provided. However, it is of course possible to provide a structure in which a necessary number of polarizing plates are separately provided. In addition to the polarizing plate, a retardation plate or the like is also required as appropriate. Of course, it may be provided accordingly.
[0031]
The transparent substrate 13 is a glass substrate formed with a thickness of about 300 μm (0.3 mm), for example, and may be equivalent to various glass substrates that have been widely used in reflection type liquid crystal display devices. The thickness of the transparent substrate 13 is merely an example, and it is a matter of course that a thicker or thinner glass substrate may be appropriately applied depending on the application. An electrode 18 is formed on the back side of the transparent substrate 13 (in other words, on the liquid crystal layer 15 side). In an actual liquid crystal display device, an alignment film is provided on the liquid crystal layer 15 side so as to cover the electrodes 18... But not shown in FIG. 1 and on an electrode 32 (described later) on the opposite metal substrate 14 side. Although an alignment film is also provided, description is omitted in FIGS. 1 and 2 and description of the alignment film is also omitted.
[0032]
The liquid crystal driving electrode 18 on the liquid crystal layer 15 side of the substrate 13 is formed from a transparent conductive material such as ITO (Indium Tin Oxide) in a stripe shape in plan view.
[0033]
On the other hand, the metal substrate 14 is, in this embodiment, at least one of Al, Mg, Ti, Be or an alloy mainly composed of each of these metal elements, for example, any of Al alloy, Mg alloy, Ti alloy, Ag alloy, and Be alloy. It consists of Since the metal substrate 14 may be a laminate, it is mainly composed of at least one of Al, Mg, Ti, Be or each of these metal elements on a thin metal plate having high strength and specific gravity as small as possible. Of course, a laminate having an alloy coating layer formed thereon may be used.
[0034]
The upper surface (surface on the liquid crystal layer 15 side) of the metal substrate 14 is subjected to a light diffusion process described below to form a light diffusion reflection surface 14A.
[0035]
The light diffusion process is a process for scattering the light reflected by the metal substrate 14 after passing through the liquid crystal layer 15. The surface of the metal substrate 14 is plastically deformed by a plastic working tool such as a metal mold on the surface. A process for forming a large number of irregularities, a process for forming irregularities on the surface of the metal substrate 14 by machining means such as machine cutting, and applying a resist to the surface of the metal substrate 14 and then etching to remove necessary portions of the surface Removing and stripping the resist, processing to make unevenness, processing to make surface unevenness by spraying abrasive grains like sandblasting, and processing to roughen the surface of the metal substrate by electropolishing Of these, processing is performed by implementing one or more methods. Since the metal substrate 14 subjected to these treatments has irregularities, has a surface gloss, and diffusely reflects light, it can be used as a reflection plate of a reflective liquid crystal display device.
[0036]
In the various methods described above, the surface of the metal substrate 14 can be light-scattered by performing dimple treatment by cutting, can also be light-scattered by finish polishing, and can be mixed with phosphoric acid and sulfuric acid by acidic etching. Light scattering can also be performed by processing at a processing temperature of 105 to 120 ° C. for the necessary time. In addition, a light diffusive reflecting surface can be formed by electropolishing. In this case, the basic methods include a perchloric acid acetic acid method, a sulfuric acid phosphoric acid method, a concentrated phosphoric acid method, a vibrating electropolishing method, a fluoroborate method, an alkali method. Any method such as a phosphate method, a sulfuric acid bath method, and an alkali method may be used. The electropolishing method is a method in which a metal such as Al is anodically electrolyzed in an electrolyte solution of an oxidant under specified conditions. In particular, an electrobranching process (Electrobrighening Process) performed at a relatively high temperature and high current density is adopted. can do. As a more specific method, the phosphoric acid bath method described in Japanese Patent No. 128891 (electrolysis is performed using a phosphoric acid bath at a current density of 20 to 60 A / dm @ 2 at a bath temperature of 50 to 70 DEG C. for about 3 to 20 minutes. By applying the method, an electropolished surface having irregularities can be easily obtained.
[0037]
The unevenness of the surface of the metal substrate 14 subjected to the light diffusion treatment by these various methods is, for example, about 0.03 to 0.25 μm in surface roughness Ra.
[0038]
Furthermore, in the structure of the present embodiment, the upper surface side (the liquid crystal layer 15 side) of the metal substrate 14 is coated with an anodic oxide film 25 having a thickness of about 1500 to 4000 angstroms. Here, if it is an anodic oxide film made of Al and made of an anodic oxide film using sulfuric acid as an electrolyte, a colorless and transparent one having good adhesion to the metal substrate 14 can be easily obtained. Therefore, there is no adverse effect on the light reflection / scattering performance of the metal substrate 14. If an anodic oxide film of Al is applied as the anodic oxide film, a pseudo γ film can be obtained by a treatment in which Al is immersed in a solution of about 10 to 30% sulfuric acid and anodized at a voltage of about 15 V to 50 V. . In various Al alloys, a colorless and transparent anodic oxide film can be obtained from AA standard 1070 alloy, 1100 alloy, 3004 alloy, 5052 alloy, 5005 alloy, 7072 alloy and the like. When these an alloys are used to form an anodized film, the color changes even under electrolytic conditions such as current density and bath temperature, but it is colorless under conditions of a bath temperature of about 15 to 25 ° C. and a current density of about 60 to 300 A / m 3. A transparent anodic oxide film can be easily obtained. The anodic oxide film is excellent in electrical insulation and has a volume resistivity of about 5 × 10 12 Ω · cm.
[0039]
Further, when the anodic oxide film 25 is formed on an alloy containing 0.5 to 2.0% of Mg in Al, the light reflectivity decreases according to the thickness of the anodic oxide film 25. The decrease in the light reflectivity is 5% when the thickness of the anodic oxide film 25 is 2 μm and 10% when the thickness is 10 μm. Therefore, if the anodic oxide film 25 is too thick, the light reflectivity is significantly decreased. In view of the above, there is no adverse effect if the thickness of the anodized film is in the above range (1500 to 4000 angstroms: 0.4 μm at the maximum).
[0040]
Next, in order to color the anodic oxide film 25 described above, the following three methods can be mainly employed.
[0041]
One uses a 10-30% solution of the sulfuric acid bath described above to produce a pseudo γ film having a film thickness of about 1500-4000 angstroms at a voltage of 15-50V. For example, as shown in FIG. 3, the anodic oxide film 25 formed under such conditions has a structure composed of a nonporous barrier layer 25A and a porous cell layer 25B. The cell layer 25B includes a cell layer 25B. In this structure, a large number of holes 25C that are long in the thickness direction are formed. By injecting a dye of a desired color into a large number of holes 25C of such a cell layer 25B, the anodic oxide film 25 can be colored to a desired color, and the holes 25C are sealed after coloring. By forming the sealing portion 25D, a colored anodic oxide film 25 having a cross-sectional structure shown in FIG. 3 is obtained. The sealing treatment can be performed by boiling with hot water after the formation of the anodized film or by exposing to hot water vapor.
[0042]
In the structure of this embodiment, the anodic oxide film 25 is partially colored, but the colored portion is color-coded according to R (red) and G (green) for each formation position of the pixel electrode 32 provided as described later. ) Or B (blue). In other words, when an electric field is applied to the liquid crystal layer 15 by the pixel electrode 32 to control the orientation of the liquid crystal molecules to switch between display, non-display, and gradation, the anodic oxide film 25 is made to correspond to one pixel as a display unit. Are color-coded by the three primary colors.
[0043]
The first method of coloring the portion corresponding to the pixel electrodes 32... By using one of the colors R (red), G (green), and B (blue) is specified using a photolithographic process. After applying a first resist that opens only the portion to be colored in one color, covers the other portion, and colors any one of the three primary colors to the portion to be colored, Remove one resist, open another part to be colored with one specific color again, and apply a second resist that covers the other part, and color the other colored part to the required colored part. Then, the second resist is peeled off, and finally, the portion to be colored with the remaining one color is opened, and a third resist is applied so as to cover the other portion, and the remaining one color is colored. The method of stripping the resist 3 may be carried out.
[0044]
Moreover, since it is necessary to close the hole portions 25C of the cell layer 25B after coloring, a sealing treatment is performed after coloring to seal the hole portion 25C to form a sealing portion 25D.
[0045]
The second method for coloring the anodic oxide film 25 is a method using an electrolytic coloring method. In order to exhibit green as an electrolytic coloring method of Al, coloring can be performed by alternating current electrolysis at 25 V in an electrolytic bath having a ratio of 30 g / l of (NH 4) 2 SO 4 and 2 g / l of CuSO 4, and colored blue [K3Fe (CN) 6] electrolytic bath may be used for this purpose, and for red coloring, an electrolytic bath having 7 g / l H2SO4 and 20 g / l CuSO4 may be used. A desired color can be applied to the anodic oxide film 25 by coating and forming a resist covering a portion other than the portion to be colored, electrolytically coloring only a necessary portion, and peeling the resist after coloring.
[0046]
The third method for coloring the anodic oxide film 25 is to form a pseudo γ film with a phosphoric acid 20 to 50% solution and a voltage of about 30 to 60 V to form a cell layer, and then perform secondary electrolysis. And then apply the above-mentioned resist to the necessary part and electrolytically treat only the necessary part, and then either R (red), G (green) or B (blue) pigment in the pores of the cell layer A method of electrodeposition can be employed.
[0047]
The surface of the anodic oxide film 25 colored by these methods may be subjected to a polishing process or the like to obtain flatness and gloss.
[0048]
Next, on the upper side (the liquid crystal layer 15 side) of the anodic oxide film 25, a TFD type switching element and a pixel electrode described below are formed.
[0049]
Data lines 30 are aligned on the anodized film 25 in a direction orthogonal to the stripe-shaped electrodes 18 at predetermined intervals, and the data lines 30 are aligned with the previous stripe-shaped electrodes 18. Thus, a plurality of pixel electrodes 32 made of a transparent conductive material such as ITO are formed through the two-terminal nonlinear element 31. In this embodiment, the two-terminal linear element 31 includes a wiring element portion 33 drawn from a data line 30 such as Ta and a conductive film 34 such as Cr formed by partially overlapping the wiring element portion 33. And a connecting portion of the pixel electrode 32 formed by partially overlapping the conductive film 34. As the two-terminal type non-linear element, as in the second example shown in FIG. 5, a first conductive film 35 made of Ta or the like formed by partially overlapping the wiring element portion 33 made of Cr or the like, A connection portion of a second conductive film 34 ′ made of Cr or the like formed by partially overlapping one conductive film 35 and a pixel electrode 32 formed by partially overlapping the second conductive film 34 ′. The element structure which is made may be adopted.
[0050]
According to the liquid crystal panel 10 of the first embodiment described above, the incident light L1 passes through the substrate 13 and the liquid crystal layer 15 and is then colored in one of R (red), G (green), or B (blue). After passing through the formed anodic oxide film 25 portion, it is irregularly reflected by the light diffusing reflection surface 14A on the surface of the metal substrate 14, and after passing through the colored portion of the anodic oxide film 25 and the liquid crystal layer 15 again, the liquid crystal is passed through the polarizing plate 16. The light is emitted from the panel 10 and reaches the observer's naked eye E as emitted light L2. Then, the alignment of the liquid crystal molecules in the liquid crystal layer 15 is controlled by adjusting the voltage applied to the electrodes 18 and 32, and the light transmission state of the liquid crystal layer 15 is adjusted to switch between display and non-display. Further, since the anodic oxide film 25 is color-coded into three primary colors of R (red), G (green) or B (blue), color display can be obtained.
[0051]
In the liquid crystal panel 10 of the first embodiment, the substrate on the back side as viewed from the observer is composed of the metal substrate 14 and is made thinner than the conventional glass substrate, so that the structure using the conventional glass substrate is used. It is lighter and thinner than the liquid crystal panel. In addition, the specific gravity is about 2.5 to 2.7 for an ordinary glass substrate, the specific gravity of Al is 2.7 for an Al metal substrate, and the strength of Al is several times the strength of glass. Considering this, it is clear that an Al substrate can be made thinner in order to obtain a substrate having the same strength. If, in addition to Al, Mg having a smaller specific gravity (specific gravity 1.7) is selected as the substrate constituent material, The substrate can be further reduced in weight.
[0052]
Furthermore, since the surface of the metal substrate 14 is a light diffusive reflecting surface 14A having a concavo-convex portion and is covered with an anodic oxide film 25 having an appropriate thickness, the metal substrate 14 has a highly efficient light reflection. Since the reflected light can be irregularly reflected without impairing the performance, a uniform and bright display with high quality can be obtained without causing unevenness of light such as interference light. Further, since the light diffusion reflection surface 14A and the anodic oxide film 25 for color display are formed very close to each other, unlike the conventional structure in which the color filter is provided on the opposite glass substrate 13 side. The problem of color misregistration is less likely to occur.
[0053]
(Second Embodiment of Reflective Liquid Crystal Display Device)
FIG. 6 is a cross-sectional view showing a liquid crystal panel 36 of a second embodiment of the reflective liquid crystal display device according to the present invention.
[0054]
Since the liquid crystal panel 36 of this embodiment has a structure obtained by changing a part of the structure of the liquid crystal panel 10 of the first embodiment, the same components as those of the previous liquid crystal panel 10 are denoted by the same reference numerals. To simplify.
[0055]
In the liquid crystal panel 36 of the second embodiment, the pixel electrodes 37 are made of metal electrodes. The material constituting the pixel electrodes 37... Made of metal electrodes is made of the same material as that of the metal substrate 14 described above. Specifically, it is made of at least one of Al, Mg, Ti, and Be or an alloy mainly composed of each of these metal elements, such as an Al alloy, Mg alloy, Ti alloy, Ag alloy, or Be alloy.
[0056]
The surface on the liquid crystal layer 15 side of the pixel electrodes 37... Is subjected to a light diffusion process equivalent to that applied to the metal substrate 14 to be a light diffusion surface 37A.
[0057]
Further, an anodic oxide film 37B is formed on the surface of the light diffusion surface 37A on the liquid crystal layer 15 side, and these anodic oxide films 37B are similar to the structure of the anodic oxide film 25 of the structure of the first embodiment. The three primary colors R (red), G (green), and B (blue) are colored.
[0058]
In addition, a light diffusion treatment is performed on the surface on the upper surface side (liquid crystal layer 15 side) of the metal substrate 14 to form a light diffusion reflection surface 14A, and the anodic oxide film 25 ′ formed thereon is What is not colored is used.
[0059]
According to the liquid crystal panel 36 of the second embodiment described above, the incident light L1 passes through the substrate 13 and the liquid crystal layer 15 and is then colored in one of R (red), G (green), or B (blue). After passing through the portion of the anodic oxide film 37, the light is diffusely reflected by the light diffusing reflection surface 37A on the surface of the metal pixel electrode 37, and again passes through the colored portion of the anodic oxide film 37B and the liquid crystal layer 15, and then passes through the polarizing plate 16. The light is emitted from the liquid crystal panel 36 and reaches the observer's naked eye E as emitted light L2. Then, the orientation of the liquid crystal molecules in the liquid crystal layer 15 is controlled by adjusting the voltage applied to the electrodes 18 and 37, and the light transmission state of the liquid crystal layer 15 is adjusted to switch between display and non-display. Further, since the anodic oxide film 37B is color-coded into three primary colors of R (red), G (green) or B (blue), color display can be obtained.
[0060]
Other effects are equivalent to the effects obtained in the first embodiment. For example, the effects of thinning, lightening, and downsizing by using the metal substrate 14 are the same as those of the first embodiment, and the effect that the problem of color misregistration hardly occurs is also the same as that of the first embodiment. is there.
[0061]
In addition, in the structure of the second embodiment, the surface on the liquid crystal layer 15 side of the metal substrate 14 is the light diffusive reflecting surface 14A. Therefore, in addition to the reflected light from the light diffusing and reflecting surface 37A of the previous pixel electrode 37, The reflected light of the light diffusing and reflecting surface 14A can also be used, and an even brighter and higher quality display can be obtained that is uniformed without causing unevenness of light such as interference light.
[0062]
By the way, in the second embodiment, the entire pixel electrode 37 is a metal electrode. However, if only the upper surface of the pixel electrode 37 is made of metal, the object can be achieved. Needless to say, the pixel electrode may have a double structure which is made of a transparent conductive material and has a metal layer formed thereon.
[0063]
(Third embodiment of reflective liquid crystal display device)
FIG. 7 is a cross-sectional view showing a liquid crystal panel 40 of the third embodiment of the reflective liquid crystal display device according to the present invention.
[0064]
The liquid crystal panel 40 of this embodiment is of a reflective type having one polarizing plate 16 as in the liquid crystal panel 10 of the first embodiment described above with reference to FIGS. The electrode is of a simple matrix type. However, the other basic structures are the same as those of the first embodiment or the second embodiment, so the same components are denoted by the same reference numerals, description of those components is omitted, and different components are mainly described below. Explained.
[0065]
The liquid crystal panel 40 of the present embodiment is composed of a metal substrate 14 on the back side of which is subjected to a light diffusion process, similarly to the structure of the first embodiment. An anodic oxide film 25 ′ is formed on the light diffusing and reflecting surface 14 A of the metal substrate 14, and the striped pixel electrode along the direction orthogonal to the striped electrode 18 on the transparent substrate 13 side on the viewer side. 41 ... are formed at regular intervals.
[0066]
The liquid crystal panel 40 of the second embodiment is different from the liquid crystal panel 10 of the first embodiment in the driving method at the time of driving the liquid crystal, but the electrode 18 is adjusted by adjusting the voltage applied to the electrodes 18 and 41 and the timing thereof. , 41 is the same as controlling the orientation of the liquid crystal molecules located between the intersecting portions and adjusting the light transmission state of the liquid crystal layer 15 to switch between display and non-display.
[0067]
The liquid crystal panel 40 of the second embodiment can obtain the same effects as the liquid crystal panel 36 of the second embodiment. That is, the liquid crystal panel 40 shown in FIG. 7 can be reduced in thickness, weight, and size. Furthermore, a uniform and bright high-quality display can be obtained without causing light unevenness such as interference light.
[0068]
(Fourth Embodiment of Reflective Liquid Crystal Display Device)
FIG. 8 is a cross-sectional view showing a liquid crystal panel 50 of a fourth embodiment of the reflective liquid crystal display device according to the present invention.
[0069]
The liquid crystal panel 50 of this embodiment is of a reflective type having one polarizing plate 16 as in the liquid crystal panel 10 of the first embodiment described above with reference to FIGS. The switching element to be driven is composed of a thin film transistor T. However, since the other basic structure is the same as that of the first embodiment, the same components are denoted by the same reference numerals, description thereof will be omitted, and different components will be mainly described below.
[0070]
The thin film transistor T as a switching element has a scanning line 51 and a signal line 52 in a matrix on an anodic oxide film 25 (having R, G, and B colored portions) as an insulating layer formed on a metal substrate 24. Are formed, and a pixel electrode 52 is provided for each region surrounded by the scanning lines 51 and the signal lines 52, and a corner portion of each pixel electrode 52 and between the scanning lines 51 and the signal lines 52 are provided. A thin film transistor including a source electrode 53, a drain electrode 54, a semiconductor 55, and a gate electrode 56 is incorporated in the portion. It is comprised so that the electricity supply control to 52 can be performed. In this embodiment, the electrode 57 formed on the opposite transparent substrate 13 side is a full-surface electrode that covers the entire pixel electrode formation region.
[0071]
In the liquid crystal panel 50 of the present embodiment, the back substrate is composed of the metal substrate 14 as in the structure of the first embodiment. An anodized film 25 is formed on the metal substrate 14.
[0072]
The liquid crystal panel 50 of the fourth embodiment differs from the liquid crystal panel 10 of the first embodiment in the configuration of the switching elements, but controls the alignment of liquid crystal molecules by adjusting the voltage applied to the electrodes 57 and 52. Similarly, the display and non-display are switched by adjusting the light transmission state of the liquid crystal layer 15.
[0073]
The liquid crystal panel 50 of the fourth embodiment can obtain the same effects as the liquid crystal panel 10 of the first embodiment. That is, in the liquid crystal panel 50 shown in FIG. 8, since the metal substrate 14 is used, thickness reduction, weight reduction, and size reduction are realizable. In the structure of the fourth embodiment, light can be diffusely reflected on the light diffusing and reflecting surface 14A on the upper surface of the metal substrate 14, so that it is uniform and bright and high quality without causing unevenness of light such as interference light. Can be obtained.
[0074]
(Embodiment of electronic device)
Next, a specific example of an electronic device including any one of the liquid crystal panels 10, 36, 40, and 50 according to the first, second, and third embodiments will be described.
[0075]
FIG. 9A is a perspective view showing an example of a mobile phone.
[0076]
In FIG. 9A, reference numeral 200 denotes a mobile phone main body, and reference numeral 201 denotes a liquid crystal display unit using any one of the liquid crystal panels 10, 36, 40, and 50.
[0077]
FIG. 9B is a perspective view illustrating an example of a portable information processing apparatus such as a word processor or a personal computer.
[0078]
In FIG. 9B, reference numeral 300 denotes an information processing apparatus, reference numeral 301 denotes an input unit such as a keyboard, reference numeral 303 denotes an information processing apparatus body, and reference numeral 302 denotes one of the liquid crystal panels 10, 36, 40, and 50 described above. The liquid crystal display unit was shown.
[0079]
FIG. 9C is a perspective view showing an example of a wristwatch type electronic device.
[0080]
In FIG. 9C, reference numeral 400 denotes a watch body, and reference numeral 401 denotes a liquid crystal display unit using any one of the liquid crystal panels 10, 36, 40, and 50.
[0081]
Each of the electronic devices shown in FIGS. 9A to 9C includes a liquid crystal display unit using any one of the liquid crystal panels 10, 40, and 50, and the first to fourth embodiments described above. The reflection type liquid crystal display devices 10, 36, 40, and 50 have the characteristics of the present invention, and even if any of the reflection type liquid crystal display devices is used, it has an excellent effect of bright display quality that is thinned, miniaturized and reduced in weight. Become an electronic device.
[0082]
【The invention's effect】
As described above, according to the liquid crystal device of the present invention, a metal substrate is used as one of the substrates sandwiching the liquid crystal layer. Therefore, even if the strength is equivalent to that of the glass substrate, the metal substrate can be made thinner than the glass substrate. Therefore, it is possible to reduce the thickness, weight, and size of the conventional reflective liquid crystal display device using a glass substrate. Next, since the surface of the metal substrate on the liquid crystal side is a direct reflection surface capable of diffusing light, the reflection efficiency is good and a bright high-quality display can be obtained.
[0083]
If at least the surface of the metal substrate is a substrate made of Al in particular, it has a specific gravity comparable to that of glass, for example, a specific gravity of about 2.7, and has a strength higher than that of glass. If it is the intensity | strength of this, a metal substrate about 1/2 to 1/3 of the thickness of a glass substrate can be employ | adopted, and a board | substrate part can be reduced in thickness or weight. The same applies to Mg, Ti, and Be. By using a substrate having at least the surface made of these metal materials in place of the glass substrate, it is possible to reduce the thickness, weight, and size.
[0084]
Furthermore, in the present invention, the three primary colors are colored on the anodized film on the metal substrate or the metal electrode, and a color filter function is provided, so that color display can be achieved without providing a color filter that has been separately provided on the opposite substrate side. Is possible. Since the anodized film on the metal substrate or metal electrode has a color filter function, an anodized film having a color filter function is provided immediately above the light reflecting surface, so that color misregistration hardly occurs and display quality is high. A bright display can be obtained.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a liquid crystal panel according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the liquid crystal panel of the first embodiment.
FIG. 3 is an enlarged cross-sectional view of an anodized film on a metal substrate provided in the liquid crystal panel.
FIG. 4 is a cross-sectional view showing a structure of a connection portion between a pixel electrode and a two-terminal linear element of the liquid crystal panel according to the first embodiment of the present invention.
FIG. 5 is a plan view showing a second example of a two-terminal linear element used in the liquid crystal panel according to the present invention.
FIG. 6 is a cross-sectional view of a liquid crystal panel according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view of a liquid crystal panel according to a third embodiment of the present invention.
FIG. 8 is a cross-sectional view of a liquid crystal panel according to a fourth embodiment of the present invention.
9A and 9B show application examples of the electronic device of the present invention, in which FIG. 9A is a perspective view showing a portable telephone, FIG. 9B is a perspective view showing an example of a portable information processing apparatus, and FIG. FIG. 9C is a perspective view showing an example of a wristwatch type electronic device.
FIG. 10 is a cross-sectional view showing an example of a conventional reflective liquid crystal display device.
[Explanation of symbols]
10, 36, 40, 50 ... Liquid crystal panel
13 ... Transparent substrate
14 ... Metal substrate
14A, 37A ... Light reflection diffusion surface
15 ... Liquid crystal layer
18, 32, 37 ... electrodes
25, 25 '... anodized film
25A ... barrier layer
25B ... cell layer
25D ... Sealing part
31. Switching element of two-terminal linear element
T ... Thin film transistor
200 ... mobile phone body
300 ... Portable information processing equipment
400 ... Watch-type electronic device

Claims (4)

A reflective liquid crystal display device,
A liquid crystal layer is sandwiched between a metal substrate and a transparent substrate disposed to face the metal substrate,
A reflective surface having a concavo-convex portion is formed on the surface of the metal substrate on the liquid crystal layer side to form a light reflection diffusion surface of the metal substrate,
An insulating layer is coated on the light reflection diffusion surface of the metal substrate,
A pixel electrode made of metal is formed on the insulating layer,
A reflective surface having a concavo-convex portion is formed on the liquid crystal side surface of the pixel electrode to form a light diffusing reflective surface of the pixel electrode,
An anodic oxide film is formed on the light diffusion reflection surface of the pixel electrode, and the anodization film is colored, and the light reflection diffusion surface of the metal substrate is also formed between the pixel electrodes. A reflective liquid crystal display device. The lower side of the pixel electrode is made of a transparent conductive material, the upper surface is made of a metal layer,
2. The reflective liquid crystal display device according to claim 1, wherein a reflective surface having an uneven portion is formed on the metal layer to form a light diffusing reflective surface of the pixel electrode. 3. The reflective liquid crystal display device according to claim 1, wherein the metal substrate is made of at least one of Al, Mg, Ti, and Be or an alloy mainly composed of the metal.   An electronic apparatus comprising the reflective liquid crystal display device according to claim 1 as a display unit.

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