JPH08194440A - Movable film type display device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a movable film type display device having a completely new structure with high reflection luminance and low power consumption. [Structure] A plurality of fixing films 2 having a first color and arranged so as to be partially overlapped with each other by being displaced by a predetermined distance in the Y direction; A plurality of movable films 6 separated in the direction and arranged in a plurality,
The first electrode is formed on the fixed film 2 and the second electrode is formed on the movable film 6, and the drive unit that moves the movable film 6 forward and backward in the Y direction by electrostatic force is connected to the electrode of the fixed film 2. Scanning line and movable film 6
In the movable film type display device including a signal line to which the electrode of (1) is connected, the scanning line potential in the non-selected state and the signal line potential when the movable film is not moved are set to a floating potential state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable film type display device capable of matrix display using a movable film.

[0002]

2. Description of the Related Art In recent years, a liquid crystal display (LCD) has been used as a display device for portable information equipment because of its demand for thinness, light weight and low power consumption. Of the LCDs, the one in which the display surface of the display is directly viewed is called the direct-view type. Direct-view LCDs include a transmissive type that incorporates a light source such as a fluorescent lamp on the back surface and a reflective type that uses ambient light. Of these, the former requires a backlight and is not suitable for low power consumption. Therefore, the latter reflective type is most popular as a display device for portable information equipment.

In a reflective LCD, a light reflection plate made of aluminum foil is L
A polarizing plate and a reflection plate having a satin-finished surface are laminated and attached to a rear glass substrate that constitutes a CD. Since such a reflective LCD does not emit light, it consumes less power.

However, this type of display device has the following problems. That is, the reflective LCD has an ECB (Electrically Controlled Birefrigence)
Mode, GH (Guest Host) mode, TN (Twisted Ne
matic) mode etc. A polarizing plate is required when using the ECB mode or the TN mode. Since the light transmittance of the polarizing plate is about 40%, the light utilization efficiency is deteriorated.

Further, when the GH mode is used, a polarizing plate is not necessary, but in order to perform full-color display, it is necessary to stack three or more monochromatic liquid crystal cells, and the light transmittance is 9%.
It is necessary to stack several layers of ITO electrodes of about 0%. Therefore, the light transmission efficiency does not become very high.

Further, in the case of color display, if an ECB mode or a GH mode is used, a color filter is not necessary, but the color reproducibility is low and the visual dependence is large. further,
When the TN mode is used, color is applied by a color filter, but since it is a reflection type, the light utilization efficiency becomes about 1/3 and it becomes dark.

In addition to this, in any mode, in order to reduce the crosstalk between the scanning electrodes and improve the image quality, a TFT (Thin Film Transistor) is used as a switch.
or) and TFD (Thin Film Diode) are provided.
The aperture ratio becomes low, and the reflection brightness decreases.

[0008]

As described above, as a display device of a portable information device, a reflective LC is conventionally used at present.
D is most suitable, but in this case as well, there is a problem that the utilization efficiency of light is low, and if the aperture ratio is low, the reflection brightness is lowered and the screen becomes dark. Therefore, there is a demand for realization of a display device having a novel structure having a high reflection brightness that cannot be obtained by an LCD.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a movable film type display device having a completely new structure which has high reflection luminance and consumes less power. .

[0010]

In order to solve the above problems, the present invention employs the following configurations. That is, the present invention has a plurality of fixing parts having a first color, which are arranged so as to be partially overlapped with each other by being shifted by a predetermined distance in the first direction, and a second color, and each of the fixing parts has a second color. At the second crossing the first direction
A plurality of movable films that are separated in the direction of, and electrodes are respectively formed on the fixed portion and the movable film, and the movable film is moved in the first direction by an electrostatic force acting between these electrodes. In a movable film type display device including a driving unit that moves back and forth, a scanning line to which the electrode of the fixed unit is connected, and a signal line to which the electrode of the movable film is connected, a scanning line in a non-selected state or It is characterized in that means for setting the potential of the signal line to a floating potential state is provided.

Here, the following may be considered as preferable embodiments of the present invention. (1) The fixed part shall be a fixed film. (2) The fixed part is a white and opaque film, and the movable film is a three-layer transparent film of cyan, magenta, and yellow. (3) Movable film is cyan, magenta, and yellow.
Consist of a black, opaque film in addition to the layer's transparent film. (4) An insulating film is interposed between the fixed part and the movable film. (5) The drive unit shall utilize the horizontal attractive force that acts between the fixed unit and the electrodes installed on or within the movable film. (6) The scanning lines are arranged in the second direction and the signal lines are arranged in the first direction. (7) The scanning lines are arranged in the second direction, some of the signal lines are arranged in the first direction, and the rest are arranged in the second direction.

[0012]

According to the present invention, the movable film arranged on the fixed portion is moved by the drive portion by electrostatic force, and this is used as a pixel, that is, a display portion to display a screen. Since a colored film is used to display the screen, a polarizing plate is not necessary, and since an electrode such as ITO is not formed in the display section, light utilization efficiency is improved. Further, since the driving unit is formed so as not to interfere with the display of the display unit, the aperture ratio becomes extremely high. As a result, the reflection brightness is increased. Further, since it has a memory function for a display image and it is not necessary to drive a new display if the display does not change, power consumption can be reduced.

In addition to this, according to the present invention, by setting the potential of the scanning line or the signal line in the non-selected state to the floating potential state, it is possible to reduce the capacitive load during driving, which further reduces the power consumption. It is possible to reduce it.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a perspective view of a movable film type display device according to an embodiment of the present invention. In the figure, 1 is a substrate,
A fixing portion 2 is a white and opaque fixing film. The fixed films 2 are arranged so as to be offset from each other in the Y direction by a certain distance and partially overlap each other. 3 is a transparent cyan film, 4 is a transparent magenta film, and 5 is an opaque yellow film.
Is composed. The movable films 6 are separately arranged on the respective fixed films 2 in the X direction. Here, the first color is white and the second color is cyan, magenta, and yellow. One end of the movable film 6 is fixed to the substrate 1,
The movement direction is limited to one dimension (Y direction).

A portion 7 of the movable film 6 is a display portion functioning as a pixel. Further, on the movable film 6, there are formed a driving unit 8 composed of a comb-shaped electrode and a wiring unit 9 drawn out from the driving unit 8 and wired. By supplying electric charges to the comb-shaped electrodes of the driving unit 8 from the wiring unit 9,
The movable film 6 moves.

When forming a display device of about 17 inches or less, one side of the display portion has a length of 40 to 300 μm.
It is preferable that the number of pixels is increased because the number of pixels can be increased to some extent. Further, the thickness of the film is preferably such that human eyes do not feel any step difference, and specifically, it is 1 to 200.
It is preferably about μm.

Further, in order to absorb the flexure generated when the movable film 6 moves, it is preferable that the wiring portion 9 has a certain length, specifically, about 5 mm to 2 cm.

The power consumption is about 1.3 W for displaying a moving image in the case of 9.5 inch size, for example.
The less you move the screen, the less. Here, FIG. 2 shows a schematic cross-sectional view of this display device. In FIG. 2, the wiring portion 9 is omitted. In the case of FIG. 2, cyan, magenta, yellow 3 is placed on the opaque white fixing film 2.
The movable films 3, 4 and 5 of transparent colors are stacked, and the fixed film 2 and the movable films 3, 4, and 5 of the same structure are stacked on the movable films 3, 4, and 5 by shifting only the display portion. Multi-color display can be performed by moving the movable film for each color separately in the direction of the arrow in the figure. For example, if magenta and yellow are left in the form of a white film, red is left, if cyan and yellow are left, green is left, if cyan and magenta are left, blue is left, and if all three colors are left, black is respectively displayed. Color multi-color display is possible.

When displaying a halftone other than eight colors,
If a specific film of the movable film is not completely moved by one pixel but is moved within one pixel by an amount corresponding to a desired halftone, multi-color display of eight or more colors can be performed by area gradation. .

Further, in order to make the black display clear, in addition to the movable transparent films 3, 4 and 5 of the three colors as shown in FIG.
Overlay the opaque black film 10 as a movable film,
A four-layer movable film can be used. When displaying in black and white instead of in color, the opaque black film 10 is laminated on the white fixed film 2 as shown in FIG.

Next, more detailed sectional structures are shown in FIGS. As described above, the cyan, magenta, and yellow transparent films are the movable films 3, 4, and 5. Basically, the color may be only in the display portion, but the entire film may be colored. As a method of coloring the film, a colorless and transparent film may be colored or dyed, or a dye may be mixed in a pellet state before forming the film. The color may be black, white, red, blue, green, etc. other than the above.

FIG. 5 shows a case where movable films are laminated as in FIGS. 1 and 2. This driving method will be described later. In FIG. 6, fixed films and movable films are alternately laminated. One pixel is formed by cyan, magenta, and yellow, or black is added to this. Each mover should be able to move independently of the others.

Here, a method of manufacturing the film will be described.
First, cyan, magenta with a thickness of 1 μm to 200 μm,
Prepare colored films such as yellow and black.
This is used as a base film. As a material, polyester, polyimide, or the like is preferable in terms of electrical characteristics and ease of manufacturing.

A single layer of any one of copper, aluminum, chromium, tantalum, tungsten, molybdenum, indium tin oxide, and carbon, or a plurality of these patterns, is formed on this film by a lithography technique or a photoengraving process. Form. This becomes an electrode.

After that, an insulating film (film) is formed on the above substances by anodizing, sputtering, vapor deposition, spin coating, dipping, printing, surface polymerization, laminating and the like. This is called a cover film. Examples of the material include a silicon oxide film, a silicon nitride film, a silicon carbide film, tantalum oxide, alumina, lead zirconate titanate, barium titanate, polyimide, polyester, polytetrafluoroethylene, polyamide, polyurethane, and polyepoxy side. is there. You may stick the film of the said material with an adhesive agent. Also, in the case of a thermoplastic resin film, the base film and the cover film can be bonded together without an adhesive.

When manufacturing an opaque white film, if magnesium oxide or barium sulfate is sputtered on the film, it becomes a perfect diffuser plate having a reflectance of 100%, and the light utilization efficiency is almost 100%. You can make a very bright display.

As the fixing portion, the thickest one can be used instead of the film. The film thus produced may be coated with Teflon or polyethylene to reduce friction and wear.

Next, a method of driving the movable film will be described. It is most effective to use electrostatic force for driving. This is because the use of electrostatic force is advantageous in reducing the size and weight.

As a method of utilizing electrostatic force, for example, FIG.
If there is a capacitor as shown in (a) and the electrodes are displaced from each other as shown in FIG. 7 (b), horizontal attractive force and vertical attractive force as shown in the figure work. By pulling an appropriate insulating film between the electrodes of the capacitor, only the horizontal attractive force can be taken out, and this is used as the driving force.

The electrostatic attraction works in the horizontal and vertical directions as shown in FIG. 7, and the horizontal attraction is used as the driving force of the film. The vertical attractive force increases the frictional force between the moving film and the fixed film, and therefore should be made as small as possible. The capacitance of the capacitor is C, the applied voltage is V, the distance between the electrodes of the capacitor is d, the dielectric constant of the dielectric in the capacitor is ε, the electrode width is W, the electrode length is L, and the horizontal movement amount of the electrode is Assuming X, the electrostatic energy U is
Is represented by U = CV ^2/2, the vertical attracting force Fd is

[0031]

[Equation 1] The horizontal attractive force Fx is

[0032]

[Equation 2] It can be expressed as. The vertical attractive force is inversely proportional to the square of the electrode distance d, and the horizontal attractive force is inversely proportional to the square of d. Therefore, if d is separated to some extent, the horizontal attractive force overcomes the frictional force, the force is applied to the electrode in the direction of increasing the capacitance of the capacitor, and the film moves. In order to drive the film continuously, the polarities of the electrodes must be changed one after another.

If the upper and lower electrodes are aligned, the horizontal attractive force does not work. Therefore, as shown in FIG. 8, there are two regions, that is, a region where the electrodes are displaced and a region where the electrodes overlap.
It is necessary to have a phase structure. The waveform of the voltage V applied to these electrodes 11 is 1/4 in the first phase and the second phase as shown in FIG.
Square waves with a periodic offset are preferred. By applying such a voltage, the movable film 6 can be driven in the direction of the arrow in the figure or in that direction. Depending on which is advanced, the movable film 6 can be advanced to the left or right in the figure. In FIG. 8, the fixing film 2 is 2
Although it has a phase structure, the movable film may have a two-phase structure.

In order to obtain a large force, a plurality of electrodes 11 shown in FIG. 8 may be arranged in parallel. Then, it is preferable that the polarities of the adjacent electrodes 11 are opposite to each other. This is because the amount of change in electrostatic energy or the amount of change in electrostatic capacitance is larger than that in the case where adjacent electrodes have the same polarity, and the generated force is larger.

The voltage waveform consists of a leading wave and a lagging wave as shown in FIG. 9. Depending on whether the first phase and the second phase are the leading wave or the lagging wave, the direction of movement is either left or right in FIG. You can

FIG. 10 shows a circuit for producing the preceding wave and the delayed wave of FIG. It is advisable to connect a photo-MOS relay to the portions A and B in the figure to separate the power source of the applied voltage of the movable film and the fixed film from the waveform generating portion. In order to completely control the movement of the movable film, it is preferable to send a desired number of pulses to the waveform generator from a pulse generator equipped with a counter circuit, rather than generating a basic clock from a function generator.

FIG. 11 is a flow chart of electrode polarities for driving the movable film. (A) → (B) →
The polarity is switched in the order of (C) → (D). here,
A method of driving each movable film when three movable films are sandwiched between two fixed films as shown in FIG.
13 is used for the explanation. 12 and 13, only the polar arrangement of electrodes is shown.

FIG. 12 shows a case where only the magenta movable film 4 is moved. First, by arranging the polarities of the electrodes as shown in FIG. 12A, and then switching the polarities of the electrodes in the order of (b) → (c) → (d), only the magenta film 4 is moved. I can go.

FIG. 13 shows a case where only the cyan movable film 3 is moved. First, by arranging the polarities of the electrodes as shown in FIG. 13A and then switching the polarities of the electrodes in the order of (b) → (c) → (d), only the cyan film 3 is moved. I can go.

In this way, the movable film at any position can be moved separately. As a result, the number of fixing films can be reduced, which is a preferable configuration for realizing a thin display device.

14 to 17 are views showing the cross sections of the movable film and the fixed film in more detail. P
Is the electrode pitch, W is the electrode width, and d is the gap between the opposing electrodes. Basically, P = 2W is preferred from the above-mentioned capacitor theory.

FIG. 14 shows the case where the insulation (film) 12 is attached to the fixing film 2 and the electrodes 11 are provided on both sides of the insulation film 12. The insulating film 12 may be attached to the movable film 6. This also applies to FIGS. 15 to 17 below.

FIG. 15 shows a case where the insulating film 12 is attached to the fixing film 2 and the electrode 11 is provided only on one side of the insulating film 12. FIG. 16 shows a case where the electrodes 11 are formed on the front and back surfaces of one or both films, and the insulating film 12 is attached to either one or both.

FIG. 17 shows the case where the electrode is embedded in the film or the electrode 11 is sandwiched and thermocompressed in the same kind of thermoplastic film. Then, the plane pattern of the electrode 11 is shown to FIG. 18 (a) (b) (c). As shown in FIG. 18A, the pitch of the electrodes 11 changes in the middle,
Those that do not change as shown in FIG. As a result, there are two regions, that is, a region where the electrodes 11 overlap each other and a region where the electrodes 11 are displaced as shown in FIG.
A phase structure can be realized. Alternatively, the structure shown in FIG. 18C may be used.

Next, the low power consumption driving method of the present invention will be described. As shown in FIG. 19, the movable film 6 and the fixed film 2 are arranged in a matrix, the signal lines 16 are arranged in the vertical direction in the drawing, and the scanning lines 14 are arranged in the horizontal direction in the drawing. The signal line 16 is connected to the signal line circuit 15, and the signal line circuit 15 distributes the image information (signal) sent to the display device to each signal line 16. In addition, the scanning line 14
Acts to select the pixel to be signaled,
It is connected to the scanning line circuit 13.

The scanning line circuit 13 internally has a soft register synchronized with the signal line circuit, and the scanning lines 14 are sequentially selected from the top or bottom of the drawing. A plurality or a single pulse that is timed with appropriate potential and signal information is sent to the selected scan line.

In the case of this embodiment, the electrode pattern of the fixing film 2 has a two-phase structure having regions where the electrode pitch is displaced as shown in FIGS.
I have a book. Further, the electrode pattern of the movable film 6 has a structure in which there is no electrode pitch deviation as shown in FIG. 18B, and has two wiring terminals. And in this case, 1
The scanning line of one row consists of 5 wires, and the fixed film 2
4 wiring terminals and one wiring terminal of the movable film 6 are connected. The signal line in one column is composed of one wiring and is connected to one wiring terminal of the movable film 6.

Here, the scanning line in the non-selected state or the signal line potential when the movable film is not moved is set as the floating potential. By doing so, it is possible to eliminate the charge / discharge that is not related to the display of the capacitance between the signal lines and the scanning lines, and it is possible to reduce the power consumption.

The switch 18 in the signal line circuit 15 determines the conducting state and the floating potential state of the signal line based on the image information. Further, the switch 17 in the scanning line circuit 13 determines the conducting state and floating state of the scanning line according to the shift register. The terminals 19 and 20 correspond to the first phase and the second phase of FIG. 8, respectively, and are adapted to send pulses that are deviated from each other by ¼ cycle.

As described above, the display device of this embodiment is a reflection type multi-color type which is inexpensive, has low power consumption, and is thin and lightweight. Since it is a reflective type, it does not require a backlight and has low power consumption. Therefore, it can be used as a display for small portable terminals such as PDAs and notebook personal computers. Furthermore, it is possible to provide beautiful multi-colored surfaces with high color reproducibility, and it is easy to manufacture and can be made large in size, so display devices such as color electronic books, color electronic encyclopedias, electronic posters and paintings that are expected to spread in the future. Can be used as

The display device of this embodiment is of a reflection type and has a high reflectance, so that it enables a paper white display, and in principle has a wide color reproduction range, a low price, and a light weight. Also, since it is a film substrate, it is possible to make as many large display devices as possible. Furthermore, since it has a memory property in principle, it has the ability to hold an image even when the power supply is in the OFF state.
Very low power consumption.

This display device can be applied to portable information devices and personal computers requiring low power consumption, as well as electronic books, electronic newspapers, electronic notebooks, electronic posters, signboards, console panels for control devices, and the like. Since this display device can perform vivid display with a color furnace similar to that of gravure printing, new applications other than the above can be considered.

The present invention is not limited to the above-described embodiments, and various modifications can be carried out without departing from the scope of the invention. In the embodiment, a part of the signal line is also floated, but only the non-selected scanning line may be floated.

[0054]

As described above, according to the present invention,
By utilizing the forward / backward movement of the movable film, it is possible to realize a movable film type display device having a completely new structure with high reflection luminance and low power consumption.

[Brief description of drawings]

FIG. 1 is a perspective view of a movable film type display device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a movable film type display device according to an embodiment of the present invention.

FIG. 3 is a sectional view of a movable film type display device according to an embodiment of the present invention.

FIG. 4 is a sectional view of a movable film type display device according to an embodiment of the present invention.

FIG. 5 is a sectional view of a movable film type display device according to an embodiment of the present invention.

FIG. 6 is a sectional view of a movable film type display device according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of vertical attractive force and horizontal attractive force acting on the capacitor electrode.

FIG. 8 is a sectional view showing an arrangement of electrodes of a movable film type display device according to an embodiment of the present invention.

FIG. 9 is a waveform diagram of a voltage applied to drive the movable film type display device according to the embodiment of the present invention.

FIG. 10 is a circuit diagram for generating a voltage applied to a movable film type display device according to an embodiment of the present invention.

FIG. 11 is a layout view of electrode polarities for driving a movable film type display device according to an embodiment of the present invention.

FIG. 12 is a layout view of electrode polarities for driving a movable film type display device according to an embodiment of the present invention.

FIG. 13 is a partial sectional view of a movable film type display device according to an embodiment of the present invention.

FIG. 14 is a partial cross-sectional view of a movable film type display device according to an example of the present invention.

FIG. 15 is a partial cross-sectional view of a movable film type display device according to an example of the present invention.

FIG. 16 is a partial cross-sectional view of a movable film type display device according to an example of the present invention.

FIG. 17 is a partial cross-sectional view of a movable film type display device according to an example of the present invention.

FIG. 18 is a plan view showing the arrangement of electrodes of the movable film type display device according to the example of the invention.

FIG. 19 is a plan view of a movable film type display device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Fixed film 6 ... Movable film 7 ... Display part 8 ... Drive part 9 ... Wiring part 10 ... Black film 11 ... Electrode 12 ... Insulating film 13 ... Scan line circuit 14 ... Scan line 15 ... Signal line circuit 16 ... Signal lines 17, 18 ... Switches 19, 20 ... Terminals

Claims (1)

[Claims] 1. A plurality of fixing portions having a first color and arranged so as to partially overlap each other by being shifted by a predetermined distance in a first direction; A plurality of movable films, which are separated from each other in a second direction intersecting the first direction, and electrodes are formed on the fixed portion and the movable film, respectively, and a static film acting between these electrodes is formed. A driving unit that moves the movable film forward and backward in a first direction by electric power, a scanning line connected to the electrode of the fixed unit, a signal line connected to the electrode of the movable film, and a scanning line in a non-selected state. Alternatively, the movable film type display device is provided with means for setting the potential of the signal line to a floating potential state.