JP3752914B2 - 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 provided with a transparent substrate and a metal substrate provided with a liquid crystal layer interposed therebetween, and an electronic device including the same, and in particular, the back side substrate is a metal substrate having a light reflection diffusion surface. Concerning structure.
[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. 9 is an enlarged schematic cross-sectional view showing the main part of an example of a conventional reflective color liquid crystal display device. The reflective color liquid crystal display device shown in FIG. 9 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 polarizing plate 106 depending on the polarization state of the reflected light. When the color is visible and opaque, it is visually recognized as a color liquid crystal display by entering the observer's naked eye E as scattered light L2 in a state where a specific color of the color filter cannot be seen.
[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. 9, a light-scattering reflective 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 without any 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]
The present invention has been made in view of the above-described problems. By using one of a pair of substrates for sandwiching a liquid crystal layer as a metal substrate and forming an insulating layer thereon, the entire apparatus is reduced in weight and size. Therefore, it is an object to provide a reflective liquid crystal display device that can be thinned and can display a bright display. It is another object of the present invention to provide a reflective liquid crystal display device which enables color display, can reduce the overall weight of the device, can be reduced in size, and can be thinned, and can obtain a bright display. I will. A further object of the present invention is to provide an electronic apparatus equipped with the above-described reflective liquid crystal display device.
[0010]
[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 diffusion reflective surface of the pixel electrode, and the metal substrate The light reflecting diffusion surface is also formed between the pixel electrodes.
[0011]
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. Thinner and lighter than conventional structures using glass substrates can be achieved. Next, since the surface on the liquid crystal side of the metal substrate is a direct reflection surface, and the light reflection diffusion surface of the metal substrate is also formed between the pixel electrodes, the reflection efficiency is good and light such as interference light is used. Bright, high-quality display that is uniformized without causing unevenness is possible.
[0012]
In the reflective liquid crystal display device of the present invention, at least the surface on the liquid crystal layer side of the metal substrate is made of at least one of Al, Mg, Ti, Be, Zn, Nb or an alloy mainly composed of these metal elements, A structure in which the insulating layer coated on the metal substrate is made of an anodic oxide film of these metals or alloys can be adopted. With these metal anodic oxide films, a uniform insulating layer can be formed on the metal substrate with good adhesion and insulation.
[0023]
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.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
(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 a cross-sectional 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 shows a color filter portion built in the liquid crystal panel. 3 is an enlarged sectional view, FIG. 3 is an exploded perspective view of the liquid crystal panel, and FIG. 4 is an enlarged sectional view of a switching element portion of the liquid crystal panel.
[0026]
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.
[0027]
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.
[0028]
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. On the back side of the transparent substrate 13 (in other words, on the liquid crystal layer 15 side), a color filter layer 17 and a driving electrode 18 are formed. In an actual liquid crystal display device, an alignment film is provided on the liquid crystal layer 15 side so as to cover the electrode 18, but it is omitted in FIG. 1 and is also aligned on an electrode 32 described later on the opposite metal substrate 14 side. Although a film is provided, it is omitted in FIG. 1 and description of the alignment film is omitted.
[0029]
As shown in an enlarged view in FIG. 2, the color filter layer 17 includes a black mask 20 for light shielding and an RGB pattern 21 for color display on the lower surface of the transparent substrate 13 (in other words, the surface on the liquid crystal layer 15 side). It is comprised by forming. Further, a transparent protective flattening film 22 that protects the RGB pattern 21 is covered.
[0030]
Such a black mask 20 is formed in a matrix by patterning a metal thin film of chromium or the like having a thickness of about 1000 to 2000 angstroms, for example, by sputtering or vacuum deposition. The RGB pattern 21 has a red pattern (R), a green pattern (G), and a blue pattern (B) arranged in a desired pattern shape. For example, a pigment dispersion method using a photosensitive resin containing a predetermined colorant They are formed by various methods such as various printing methods, electrodeposition methods, transfer methods, and dyeing methods.
[0031]
A liquid crystal driving electrode 18 is formed on the color filter layer 17 on the liquid crystal layer 15 side. The liquid crystal driving electrode 18 is formed from a transparent conductive material such as ITO (Indium Tin Oxide) in a stripe shape in plan view.
[0032]
On the other hand, in this embodiment, the metal substrate 14 is made of at least one of Al, Mg, Ti, Be, Zn, Nb or an alloy mainly composed of each of these metal elements, for example, an Al alloy, Mg alloy, Ti alloy, Be alloy, It consists of either Nb alloy or Zn alloy. In addition, since the metal substrate 14 may be a laminate, at least one of Al, Mg, Ti, Be, Zn, and Nb on the thin metal plate with high strength and specific gravity as small as possible or these. Of course, a laminated plate in which a coating layer of an alloy mainly composed of each metal element is formed may be used.
[0033]
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.
[0034]
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.
[0035]
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.
[0036]
The unevenness of the surface of the metal substrate 14 subjected to the light diffusion treatment by these various methods is, for example, about 0.05 to 0.35 μm (10 −6 m) in terms of the surface roughness Ra.
[0037]
Further, 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 insulating layer 25 of an anodic oxide film having a thickness of about 1500 to 3000 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 this anodic oxide film, a colorless and transparent anodic oxide film (beta film) is obtained by immersing Al in a solution of about 10 to 30% sulfuric acid and anodizing at a voltage of 100 V or more. Can be obtained. 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.
[0038]
Further, when an anodic oxide film is formed on an alloy containing 0.5 to 2.0% of Mg in Al, the light reflectance is lowered according to the thickness of the anodic oxide film. The decrease in light reflectivity is 5% when the thickness of the anodized film is 2 μm (10 −6 m) and 10% when the thickness is 10 μm (10 −6 m). However, there is no adverse effect if the thickness of the anodized film is within the above range (1500 to 3000 angstroms) from the viewpoint of light reflectance.
[0039]
As the insulating layer 25, a spin-coating method is applied to a silicon oxide (SiO2) film having a thickness of about 1500 to 3000 angstroms obtained by dipping or sputtering, or a colorless and transparent organic film such as an epoxy resin or an acrylic resin. Alternatively, an organic resin insulating film having a thickness of about 1.0 to 2.0 μm (10 −6 m) formed by coating or printing may be used.
[0040]
Next, a TFD type switching element and a pixel electrode described below are formed on the insulating film 25.
[0041]
Data lines 30 are aligned on the insulating layer 25 in a direction perpendicular to the stripe-shaped electrodes 18 and spaced apart from each other by a predetermined distance, and are aligned with the previous stripe-shaped electrodes 18 between the data lines 30. 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.
[0042]
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, and this From a connection portion between a second conductive film 34 ′ made of Cr or the like formed by partially overlapping the first conductive film 35, and a pixel electrode 32 formed by partially overlapping the second conductive film 34 ′. A configured element structure may be adopted.
[0043]
According to the liquid crystal panel 10 of the first embodiment, the incident light L1 passes through the liquid crystal layer 15 and is irregularly reflected by the light diffusion reflection surface 14A on the surface of the metal substrate 14, and after passing through the liquid crystal layer 15 again, the color filter layer 17 , And is emitted from the liquid crystal panel 10 through the polarizing plate 16 and reaches the observer's naked eye E as outgoing 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.
[0044]
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.
[0045]
Furthermore, since the surface of the metal substrate 14 is formed as a light diffusing reflection surface 14A on which uneven portions are formed and is covered with a transparent insulating layer 25, the high light reflectivity of the metal substrate 14 is impaired. Since the reflected light can be irregularly reflected, a uniform and bright display with high quality can be obtained without causing light unevenness such as interference light.
[0046]
(Second Embodiment of Reflective Liquid Crystal Display Device)
FIG. 6 is a cross-sectional view showing a liquid crystal panel 40 of a second embodiment of the reflective liquid crystal display device according to the present invention.
[0047]
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, 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.
[0048]
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 insulating layer 25 is formed on the light diffusing and reflecting surface 14A of the metal substrate 14, and striped electrodes 41 along a direction orthogonal to the striped electrodes 18 on the observer-side transparent substrate 13 side. It is formed at regular intervals.
[0049]
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 liquid crystal driving, but the liquid crystal molecules are adjusted by adjusting the voltage applied to the electrodes 18 and 41 and the timing thereof. It is the same that the display control and non-display switching are performed by controlling the orientation of the liquid crystal layer 15 and adjusting the light transmission state of the liquid crystal layer 15.
[0050]
The liquid crystal panel 40 of the second embodiment can obtain the same effects as the liquid crystal panel 10 of the first embodiment. That is, the liquid crystal panel 40 shown in FIG. 6 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.
[0051]
(Third embodiment of reflective liquid crystal display device)
FIG. 7 is a cross-sectional view showing a liquid crystal panel 50 of the third embodiment of the reflective liquid crystal display device according to the present invention.
[0052]
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. It is not a transparent conductive material but a metal electrode made of an opaque metal material with good light reflectivity. 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.
[0053]
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 insulating layer 25 is formed on the metal substrate 14, and pixel electrodes 27 are formed in parallel in a matrix so as to be aligned with the stripe-shaped electrodes 18 on the observer-side transparent substrate 13 side. Further, the structure of the switching element for driving the pixel electrode 27 is a two-terminal linear element having a structure similar to that of the first embodiment.
[0054]
Here, the pixel electrodes 27 are made of a material equivalent to the material constituting the metal substrate 14 of the first embodiment. For example, a pixel of metal from at least one of Al, Mg, Ti, Be, Zn, and Nb or an alloy mainly composed of each of these metal elements, such as an Al alloy, Mg alloy, Ti alloy, Ag alloy, or Pt alloy. An electrode 27 is formed. The upper surface (surface on the liquid crystal layer 15 side) of the metal pixel electrode 27 is subjected to the light diffusion process described above to form a light diffusion reflection surface 27A.
[0055]
The liquid crystal panel 50 of the third embodiment is different from the liquid crystal panel 10 of the first embodiment in the constituent material of the pixel electrode 27, but the alignment of liquid crystal molecules is controlled by adjusting the voltage applied to the electrodes 18 and 27. It is the same to switch between display and non-display by adjusting the light transmission state of the liquid crystal layer 15.
[0056]
The liquid crystal panel 50 of the third embodiment can obtain the same effect as the liquid crystal panel 10 of the first embodiment. That is, in the liquid crystal panel 50 shown in FIG. 7, since the metal substrate 14 is used, thickness reduction, weight reduction, and size reduction are realizable. In the structure of the third embodiment, light can be diffusely reflected on the light diffusing and reflecting surface 27A on the upper surface of the pixel electrode 27, so that it is uniform and bright and high quality without causing light unevenness such as interference light. An indication can be obtained. In addition, in the structure of the third embodiment, since the surface of the metal substrate 14 on the liquid crystal layer 15 side is the light diffusive reflecting surface 14A, in addition to the reflected light of the light diffusing / reflecting surface 27A of the previous pixel electrode 27, 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.
[0057]
By the way, in the third embodiment, the entire pixel electrode 27 is a metal electrode. However, if only the upper surface of the pixel electrode 27 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.
[0058]
Further, the switching element for driving the pixel electrode 27 is not limited to the two-terminal linear element as in the present embodiment, and it goes without saying that an active driving element using a thin film transistor may be used as appropriate.
[0059]
(Embodiment of electronic device)
Next, a specific example of an electronic apparatus including any one of the liquid crystal panels 10, 40, and 50 according to the first, second, and third embodiments will be described.
[0060]
FIG. 8A is a perspective view showing an example of a mobile phone.
[0061]
In FIG. 8A, 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, 40, and 50.
[0062]
FIG. 8B is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer.
[0063]
8B, 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 a liquid crystal using any one of the liquid crystal panels 10, 40, and 50. The display part is shown.
[0064]
FIG. 8C is a perspective view showing an example of a wristwatch type electronic device.
[0065]
In FIG. 8C, 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, 40, and 50.
[0066]
Each of the electronic devices shown in FIGS. 8A to 8C includes a liquid crystal display unit using any one of the liquid crystal panels 10, 40, and 50, and the first to third embodiments described above. The reflective liquid crystal display device 10, 40, 50 has the characteristics of the electronic device having an excellent effect of bright display quality that is thinned, miniaturized, and reduced in weight regardless of which reflective liquid crystal display device is used. It becomes.
[0067]
【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.
[0068]
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, Be, Zn, and Nb. By using a substrate made of these metal materials at least on the surface in place of the glass substrate, reduction in thickness, weight, and size can be achieved.
[0069]
Furthermore, in the present invention, the insulating layer may have a structure made of a silicon oxide film or an organic resin film, and even with these structures, sufficient insulation of the metal substrate can be obtained.
[0070]
Further, in the present invention, color display is possible by providing a color filter layer on the liquid crystal layer side of the transparent substrate.
[0071]
Further, in the present invention, in the case where the metal electrode for driving the liquid crystal on the insulating layer on the metal substrate is formed, a reflection surface having an uneven portion is formed on the surface of the metal electrode on the liquid crystal side so that light reflection and diffusion is performed. Since the surface is formed, the light reflected on the light diffusion reflection surface of the metal electrode can be switched between transmission and non-transmission by controlling the alignment of the liquid crystal molecules of the liquid crystal layer. Even in this structure, a metal substrate is used instead of the conventional glass substrate, so it is possible to use a metal substrate that is thinner than the glass substrate, making it thinner, lighter, and smaller than the conventional structure using the glass substrate. Is possible. Further, in this structure, the light diffusion reflection surface on the liquid crystal side of the metal electrode and the light diffusion reflection surface on the liquid crystal side of the metal substrate are used as the reflection surfaces, so that the reflection efficiency is further improved and a bright high quality display can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a liquid crystal panel according to a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view showing a color filter layer portion of the liquid crystal panel shown in FIG.
FIG. 3 is an exploded perspective view of the liquid crystal panel according to the first embodiment of the present invention.
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.
8A and 8B show application examples of the electronic device of the present invention, in which FIG. 8A is a perspective view showing a portable telephone, FIG. 8B is a perspective view showing an example of a portable information processing apparatus, and FIG. FIG. 8C is a perspective view showing an example of a wristwatch type electronic apparatus.
FIG. 9 is a cross-sectional view showing an example of a conventional reflective liquid crystal display device.
[Explanation of symbols]
10, 40 ... Liquid crystal panel
12 ... Sealing material
13 ... Transparent substrate
14 ... Metal substrate
15 ... Liquid crystal layer
17 ... Color filter layer
18, 32 ... Electrodes
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,
A reflective liquid crystal display device, wherein a light reflection diffusion surface of the metal substrate is also formed between the pixel electrodes. 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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