JPH11265167A - Non-radiative color display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-radiative color display, which requires low power and can generate a high quality image, and a multiplex addressing method for the above display. SOLUTION: In a non-radiative color display 10 with which plural color pixels showing an input image are displayed in response to an input image, display pixels 40 are arranged in the shape of a matrix in response to an impressed electric field so as to change the density of colors in that display corresponding to that impressed electric field. Drive electronics 20 generate the pixels of a desired color density by generating an electric field selectively to these display pixels 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the field of non-emissive color display devices. More specifically, the present invention relates to a non-emissive color display device that changes optical density using electric field driven solid phase particles.

[0002]

2. Description of the Related Art Non-emissive displays display information by changing the optical density on the display surface.

A disadvantage of emissive displays is that this type of display requires the use of power to generate light. The use of liquid crystal displays
This corresponds to this case. This display is provided with a switching element for controlling light. Separate light generation means is required to generate light.

[0004] Of course, liquid crystal displays (LCDs) are well known in the art and are used in various cameras. Liquid crystal displays use liquid crystal phase molecules to change the polarization of light. The user views the image on the display through a pair of crossed polarizers that are part of the display. The polarizer causes a significant amount of light loss and degrades the observed image. To overcome this problem, LCDs use a significant amount of power. Also, it is difficult to obtain high levels of density change that can affect the quality of the image on the display.

[0005] There are various types of non-emissive displays using electric field driven solid phase particles. One class is
This is a so-called electrophoretic display, which is based on the principle of movement of charged particles in an electric field. In electrophoretic displays, charged particles having different reflective optical densities are moved by an electric field toward or away from the viewing side of the display, thereby creating a contrast in optical density. Another class of electric field driven particles used in non-emissive displays are particles that contain an electric dipole. Each pole of the particle is
It is associated with different optical densities (dichroism). The electric dipole can be oriented in two directions by a pair of electrodes, orienting each of the two polar surfaces in the viewing direction. The different optical densities in the two hemispheres of the particles thus create a contrast in optical density.

[0006]

A problem with non-emissive displays using electric field driven solid phase particles is that such displays are all monochrome.
Monochrome is understood to mean the ability to display pixels along a single color curve (CHROMATICITY CURVE). The color curve is terminated at each of its ends by a minimum and maximum color density.

[0007] Another need for non-emissive displays based on electric field driven solid phase particles is to provide efficient driver circuits for the pixels. These displays typically have multiple pixels.
The requirement that each display pixel be driven by a separate electrical driver can severely limit the size of the display panel.

It is an object of the present invention to provide a non-light emitting type color display device which requires low power and can generate a high quality image.

Another object of the present invention is to provide a multiplexed addressing scheme for a non-emissive color display device.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-emissive color display device for displaying a plurality of color pixels representing an image in response to an input image, comprising: a) responding to an applied electric field; Are arranged in a matrix,
And b) an electric field driven solid phase particle configured to change a color density in the display according to the applied electric field; and b) generating an electric field selectively with respect to the electric field driven solid particle. And an electric driver for generating a pixel having a desired color density.

As an advantage of the present invention, a very efficient display using low power can be obtained by using electric field driven solid phase particles appropriately selected to form a color image.

It is a feature of the present invention that the non-emissive color driven solid phase particles can be used effectively in displays and respond to electric fields using very low power.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to a display device capable of displaying a color image.

Referring to FIG. 1, there is shown a schematic diagram of a display device 10 according to the present invention. The display device 10 includes drive electronics 20 and a non-emissive color display 30. The arrangement of the display pixels 40 is shown distributed in rows and columns. Row is R
1, R2, R3,. . . And the like. The columns are C1, C2, C3,. . . And the like. Each display pixel 40 is indicated by its row and column number. The display device is M
It has rows and N columns.

A first embodiment of the present invention will be described below. 2A and 2B show a more detailed cross-sectional view of the non-emissive color display 30 along line 2-2 of FIG. Non-emissive color display 30 is shown as having a plurality of electric field driven solid phase particles 100. In FIG. 2, the electric-field-driven solid-phase particles 100 are dichroic particles, that is, half of the particles are white, and the other half are black, yellow, magenta, cyan, red,
It is illustrated as having different color densities, such as green and blue. Dichroic particles are electrically bipolar. Each of the color surfaces (eg white and black)
Points to one pole in the dipole direction. The term "electrically driven solid phase particles" is understood to include particles which are typically solid phases immersed in a fluid within microcapsules. The electric field driven solid phase particles 100 are suspended in a fluid 110, such as oil, which is encapsulated in microcapsules 120. The microcapsules 120 are immersed in the matrix 130. The addressing electrodes are arranged in a pixelated manner as pairs of an upper electrode 150 above and a lower electrode 160 below the substrate. The upper electrode 150 is made of a transparent conductive material such as indium tin oxide (ITO) in order to view the electric field driven solid phase particles 100. When a potential difference is applied between each pair of addressing electrodes, microcapsules 120
Electric field induced solid phase particles 100
Are aligned in the low energy direction, and the ends of the dipoles are respectively directed to electrodes of opposite polarity. FIG. 2A shows that a negative potential is applied to the upper electrode 150 and a positive potential is applied to the lower electrode 1.
Shown are the particles 100 in a white state applied to 60. FIG. 2B shows the particles 100 in a black state where a positive potential is applied to the upper electrode 150 and a negative potential is applied to the lower electrode 160. The state of the particle 100 depends on the applied electric field and does not depend on the previous state of the particle 100. Non-luminous color display 30
Can perform multiple writes and erases without affecting performance. The terms write and erase will be understood as applying a voltage to set the particles to a desired color or background color, respectively. For the application, any color may be used as the background color. Details of the preparation of dichroic dipole particles and their addressing arrangement are described in US Pat.
Nos. 43,103, 5,344,594, and 5,
604,027 and Proce by Saito et al.
edings of the SID, Vol. 23/4 (1982), pp. 249-253, "A Newly Developed Electric Twisted Ball Display (A Newly
Developed Electric Twi
Sting Ball Display), the disclosures of which are hereby incorporated by reference. Another example of a display using field-driven particles is described in PCT Patent Application No. WO 97/04.
No. 398, which is an electrophoretic display. However, it is understood that the present invention is compatible with many other types of field-driven particles that can display different color densities under the influence of an electrically activated field (application of an electric field). You.

In FIG. 3, the drive electronics 2 of FIG.
0 are depicted as passive array multiple addressing circuits according to the first embodiment of the present invention. Capacity 220
And the resistor 230, the lamp parameter equivalent impedance 21 of the pixel including the electric field driven solid phase particles 100, the microcapsules 120 and the matrix 130 between a pair of electrodes.
0. The electrical driver 260 of FIG. 3 is illustrated as a metal oxide semiconductor field effect transistor (MOSFET) as a preferred embodiment of the present invention. Specifically, the MOSFET of FIG. 3 is an N-channel enhanced mode MOSFET. In FIG. 3, the source, gate, and drain of the MOSFET are “S”,
Symbols “G” and “D” are given. The substrate of the electrical driver 260 is well insulated. this is,
This can be achieved by biasing the substrate more negatively than the drain "D" or by fabricating the device on a passive substrate as in thin film technology. The source "S" of the MOSFET electrical driver is connected to ground. MOSFET is a complementary metal oxide semiconductor (CMO).
S) Using technology, it can be manufactured on a silicon-based substrate. MOSFETs can also be fabricated on passive substrates using thin film or thick film amorphous silicon technology. It should be noted that other devices, such as analog switches formed using bipolar junction transistors (BJTs), may also be used in the present invention. The upper electrode 150 in FIGS. 2A and 2B is connected to the drain “D” of the electric driver 260. The row selection electrode 240
Connected to gate “G” of electrical driver 260. The lower electrode 160 in FIGS. 2A and 2B is connected to the output of the electric driver 200. Column electrode 250
Is connected to the input of the electrical driver 200. Electrical driver 200 is illustrated in the present invention as a MOSFET source follower. Electric driver 200
Provides bipolar driving capability. That is, positive and negative power are supplied. It should be noted that in the present invention, various output stages can be used as devices, and other driver devices and technologies such as BJT can be used as technologies. The pixels 40 in each row of the two-dimensional array of pixels are activated in parallel (activate: applying an electric field). For example, when the electric driver 260 in the row R1 is activated (activated: on), the voltage of each column electrode 250 is changed by the electric driver 200 to each lower electrode 16.
0 is applied. The charge is stored in each capacitor 220 in row R1. Each pixel in row R1 is addressed. In the present embodiment, a total of (M + N) electrical drivers and (M + N)
N) There are conductive wires.

FIGS. 4A and 4B show a line 2-2 in FIG.
2 shows a more detailed cross-sectional view of a non-emissive color display 30 according to a second embodiment, taken along line II. The second embodiment includes a semiconductor substrate 140 with an expanded pixel configuration. Semiconductor substrate 140 provides driver electronics for bottom electrode 160. Semiconductor substrate 140
Is preferably formed using thick film amorphous silicon. It is understood that the semiconductor substrate of the present invention is compatible with many other semiconductor materials.

FIG. 5 shows a second embodiment of the present invention. The drive electronics 20 of FIG. 1 is depicted as an active array multiple addressing circuit. As in the first embodiment of the present invention, the capacitor 220 and the resistor 230
Means electric field driven solid phase particles 100 and microcapsules 1
20 is an equivalent impedance 210 of the pixel including the matrix 20 and the matrix 130. Additional circuit elements may be added for more accurate equivalent circuit impedance. Details of the MOSFET driver are as discussed in the discussion of the first embodiment of the present invention. The upper electrode 150 is connected to the drain of the electric driver 260. The row selection electrode 240 is connected to the gate of the electric driver 260. The lower electrode 160 is connected to the ground. For each row, an electrical driver 20
0 is illustrated as the MOSFET source follower of the present invention. It should be noted that in the present invention, various output stages can be used as devices, and other driver devices and technologies such as BJT can be used as technologies. The pixels 40 in each row of the two-dimensional array of pixels are activated (electric field applied) in parallel. For example, when the row electrode 240 of the row R1 is activated (activated: operation voltage is applied),
Each of the electrical drivers 260 in row R1 is conductive (on)
The electric driver 200 of each column is connected to each column electrode 25
0 and a voltage are applied to the lower electrode 160. The charge is in row R
1 is stored in each capacity 220. Each pixel in row R1 is addressed. In this embodiment, in order to address the non-light emitting type color display 30, a total of (M × N + N) is used.
There are electrical drivers and (M + N) conductive wires.

FIG. 6 shows the arrangement of color pixel patterns in a non-emissive color display 30 according to the present invention. The arrangement of the display pixels 40 is shown distributed in rows and columns. The rows are R1, R2, R3,. . . And the like. The columns are C1Y, C1M, C1
C, C2Y, C2M,. . . And the like. Each display pixel 40 is indicated by its row and column number. The display pixels 40 are dichroic pixels. As is well known in the art, full color non-emissive displays typically require at least three colors: yellow, magenta, and cyan. In addition, black, red, green, blue, and other colors can be added to extend the amount of color range.

The display pixels 40 of FIG.
The electric field driven solid phase particles 100 are included. Row C1
Y, C2Y, C3Y,. . . The yellow display pixel 40, which is connected to the pixel, includes electric-field-driven solid-phase particles 100 that are half yellow and half white. Columns C1M, C2M, C3M,. . . The magenta display pixel 40, which is connected to, includes electric field driven solid phase particles 100 that are half magenta and half white. Columns C1C, C2C, C3C,. . . The cyan display pixel 40, which is connected to the pixel, includes electric field driven solid phase particles 100 that are half cyan and half white. The apparatus has the columns C1Y, C1M, C1C, C2Y, C
It is driven similarly to the second embodiment, except that 2M has its own electric driver 200. The display device has a total of M rows and 3 × N columns. In the present embodiment, the non-emission type color display 30
To address (3 × M × N + 3 × N)
There are electrical drivers and (M + 3 × N) conductive wires. Color is formed by selecting a combination of color pixels as shown in Table 1 below.

[0021]

[Table 1] Combination of color pixels Desired color Yellow display Magenta display Cyan display pixel 40 pixels 40 pixels 40 White White White White Cyan White White Cyan Magenta White Magenta White Yellow Yellow White White Red Yellow Magenta White Green Yellow White Cyan Blue White Magenta according cyan invention, can also be obtained many other pixel color patterns, it is understood.

Although the present invention has been described in detail with particular reference to certain preferred embodiments, it will be understood that various changes and modifications can be made within the spirit and scope of the invention. Would.

[Brief description of the drawings]

FIG. 1 is a partial schematic diagram showing a display device according to the present invention.

FIG. 2 is a more detailed cross-sectional view of the non-emissive color display 30 taken along line 2-2 of FIG. 1, illustrating different states of the electric field driven solid phase particles.

3 shows an addressing circuit for the display device of FIG. 1, including a lamp element model showing the pixels of the display of FIG. 2;

FIG. 4 is a more detailed cross-sectional view of the non-emissive color display 30 taken along line 2-2 of FIG. 1, showing different states of the electric field driven solid phase particles in another embodiment. .

FIG. 5 illustrates another embodiment of an addressing circuit for the display device of FIG. 1 including a lamp element model showing pixels of the display of FIG. 2;

FIG. 6 shows a color pattern of pixels in a display according to the invention.

[Explanation of symbols]

10 display device, 20 drive electronics, 30 non-luminous color display, 40 pixels,
100 electric field driven solid phase particles, 110 fluid, 120
Microcapsule, 130 matrix, 140 semiconductor substrate, 150 upper electrode, 160 lower electrode, 170
Ground, 200 electrical driver, 210 impedance, 220 capacitance, 230 resistance, 240 row electrode, 250 column electrode, 260 electrical driver.

Claims (3)

[Claims] 1. A non-emissive color display device for displaying a plurality of color pixels representing an image in response to an input image, comprising: a) being arranged in a matrix in response to an applied electric field;
And b) an electric field driven solid phase particle configured to change a color density in the display according to the applied electric field; and b) generating an electric field selectively with respect to the electric field driven solid particle. A non-light-emitting color display device, comprising: an electric driver for generating a pixel having a desired color density. 2. A non-emissive color display device for displaying a plurality of color pixels indicative of an image in response to an input image, comprising: a) being arranged in a matrix in response to an applied electric field; And b) a plurality of electrode pairs, each pair intersecting at a pixel, wherein the display includes electric field driven solid phase particles configured to change a color density in the display in response to the applied electric field. And applying an electric field in two directions opposite to each other to the electric field driven solid phase particles, and c) being coupled to the electrode, the electrode generating an electric field in a desired direction to produce a desired color. Electrical driver means for selectively applying a voltage to the electrodes to generate a concentration. 3. The non-emission type color display device according to claim 2, wherein said electric driver means comprises a plurality of electric drivers and an electric driver for addressing said electric drivers to said electric drivers. An electrical addressing circuit for generating an electric field that controls movement of the solid particles, and
Non-emission type color display device.