JP2000284322A - Active matrix substrate and spacial optical modulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spacial optical modulating device having high definition modulating pixels which are not obtd. in a conventional device. SOLUTION: This spacial modulation device consists of an active matrix substrate 102 having switching elements 101 for driving pixels, a transparent substrate 103 facing the substrate 102, and an electro-optic medium 104 held between the substrates. The electro-optic medium corresponding to the pixel 105 is equipped with at least two driving electrodes 107 to apply an electric field and with a pixel separator 106 to physically separate pixels arranged on the active matrix substrate 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a spatial light modulator.

[0002]

2. Description of the Related Art A conventional spatial light modulator has a structure in which an electric field is applied above and below an electro-optic medium.

[0003] Also, ASIA DISPLAY 98 p.
371, a vertical electric field type liquid crystal display mode called an FFS mode, SID98 DIGEST p. No. 389, a lateral electric field type liquid crystal display mode called an IPS mode has been developed.

[0004]

However, in such a conventional spatial light modulator, when an attempt is made to realize a fine pixel, there is a leakage electric field from an adjacent pixel and interference of orientation, resulting in a high definition. There is a problem that it is difficult to obtain a proper modulation pixel.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a spatial light modulator having high-definition modulation pixels.

[0006]

In order to achieve the above object, a pixel is formed by a plurality of electrodes, a switching element is formed on each electrode, and the pixels are formed in a matrix. It is characterized by. Further, a plurality of wirings are formed to be connected to the switching element, and a driving circuit is formed to be connected to each of the wirings.

[0007] With such a configuration, the voltage control of the pixel in the minute area can be performed by the switching element. More preferable control becomes possible by connecting the switching elements to all the electrodes existing in the pixel region.

Further, the spatial modulation device of the present invention comprises an active matrix substrate in which pixels are formed by a plurality of electrodes, and a switching element is formed on at least one of the plurality of electrodes; In a spatial light modulator in which an electro-optical medium is sandwiched between a substrate and a substrate disposed opposite to the substrate, a pixel separator for dividing a pixel region is formed in each pixel.

According to this, even if the spatial light modulator has a pixel structure with a higher density, it is possible to configure a spatial light modulator relating to amplitude and phase with high accuracy and eliminating the influence of adjacent pixels.

Further, the electrodes are formed on the same or close planes, that is, on another layer via an insulating layer.

According to this, a high-density pixel can be realized by freely applying a fine processing process.

Further, the electrode has a reflection characteristic.

According to this, the active matrix substrate does not need to be transparent, and a high density reflective pixel can be realized.

Further, the electro-optical medium is a liquid crystal.

According to this, it is possible to realize a high-density pixel in which the influence of the orientation of adjacent pixels is blocked by the pixel separator.

Further, there is provided a spatial light modulator, wherein the pixel separator is a photopolymerized polymer.

According to this, the adjacent pixels can be finely divided, and the influence of the orientation of the adjacent pixels can be eliminated.

Further, the active matrix substrate is made of M
It is a silicon wafer on which an OS transistor is formed.

According to this, a high-definition pixel can be realized by freely applying the Si fine processing process.

Further, at least one of the electrodes constituting the pixel is connected to a switching element.

According to this, high-precision light modulation with respect to amplitude and phase without the influence of adjacent pixels can be performed.

Further, at least one of the electrodes constituting the pixel is connected to a switching element,
The other drive electrode is connected to a wiring having a specific potential.

According to this, it is possible to perform light modulation on amplitude and phase with high accuracy while eliminating the influence of adjacent pixels.

Further, an electrode connected to a wiring having a specific potential constituting a pixel is connected to an adjacent selection signal line.

According to this, an equivalent device structure can be realized with less wiring.

Further, the switching element, the wiring, and the storage capacitor are provided at positions overlapping the pixel separator in plan view.

According to this, it is possible to suppress a decrease in the aperture ratio, and to realize a high-definition pixel whose aperture ratio does not depend on the size of the electrode.

Further, the electrodes constituting the pixel are connected to switching elements for driving adjacent pixels.

According to this, an equivalent device structure can be realized with less wiring and fewer elements.

Further, a driving signal for giving a signal corresponding to a difference potential of a display data column is applied to a signal line for sending display data to a pixel driving switching element to which the electrode constituting the pixel is connected. And

According to this, a device structure with a small leakage electric field between horizontally adjacent pixels can be realized.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

[Configuration of Liquid Crystal Panel] FIGS. 11 and 12
1 is a plan view of the liquid crystal panel used in the spatial light modulator according to the present embodiment, as viewed from the counter substrate side, and FIG.
FIG. 4 is a cross-sectional view of the liquid crystal panel when cut along a line −H ′.

11 and 12, a liquid crystal panel 1 has an active matrix substrate 200 on which electrodes are formed in a matrix, and a counter substrate 400 on which a counter electrode 532 and a light-shielding film 531 formed as necessary are formed.
And a liquid crystal 539 sealed and sandwiched between these substrates.
It is schematically composed of The active matrix substrate 200 and the opposing substrate 400 are bonded together with a predetermined gap therebetween by a sealing material 552 including a gap material formed along the outer peripheral edge of the opposing substrate 400.

Between the active matrix substrate 200 and the counter substrate 400, a liquid crystal sealing region 540 is defined by a sealing material 552.
Liquid crystal 539 is sealed in 40. In the liquid crystal sealed area 540, the active matrix substrate 200
A spacer 537 may be interposed between the substrate and the counter substrate 400. As the sealant 552, an epoxy resin, various ultraviolet curable resins, or the like can be used. Further, as a gap material to be mixed with the sealing material 552,
An inorganic or organic fiber or sphere of about 2 μm to about 10 μm is used.

Here, since the sealing material 552 is partially interrupted, the interrupted portion causes the liquid crystal injection port 54 to break.
1 is configured. For this reason, after the opposing substrate 400 and the active matrix substrate 200 are bonded to each other, if the inside region of the sealant 552 is set in a reduced pressure state, the liquid crystal 539 can be injected under reduced pressure from the liquid crystal injection port 541. The liquid crystal injection port 541 may be closed with the sealant 542. The opposing substrate 400 is also provided with a light shielding film 555 for cutting off the image display area 80 inside the sealant 552. The active matrix substrate 200 and the opposing substrate 40
An upper / lower conductive material 556 for establishing electrical continuity between the upper and lower conductive members is formed. Further, depending on the type of liquid crystal 539 to be used, the operation mode, and whether the liquid crystal 539 is normally white mode or normally black mode, a polarizing film is provided on the light incident side surface or the light emission side of the counter substrate 400 and the active matrix substrate 200. , A retardation film, a polarizing plate and the like are arranged in a predetermined direction.

In this embodiment, the opposing substrate 400 is smaller than the active matrix substrate 200, and the peripheral portion of the active matrix substrate 200 is stuck so as to protrude from the outer peripheral edge of the opposing substrate 400. Accordingly, the driving circuits (the scanning line driving circuit 70 and the data line driving circuit 60) and the input / output terminals 545 of the active matrix substrate 200 are in a state of being exposed from the counter substrate 400.

FIG. 1 is a sectional view showing an outline of the present invention. A liquid crystal, which is an electro-optical medium 104, is sandwiched between an active matrix substrate 102 having a switching element 101 for driving a pixel and a transparent substrate 103.
Is driven by at least two electrodes on the active matrix substrate. Further, the pixel 105 is separated from the adjacent pixel by the pixel separator 106, and has a structure that is hardly affected by the liquid crystal alignment of the adjacent pixel. A driving electric field is applied to the electro-optical medium by at least two driving electrodes 107 provided on the active matrix substrate. At least two drive electrodes are arranged in one pixel, and a horizontal electric field or a vertical electric field is applied to the electro-optical medium depending on a potential between the electrodes. The pixels are physically divided into one pixel by one pixel by a pixel separator. This eliminates the influence of the change in the orientation of the surrounding pixels. This effect is more prominent in high-density devices in which the pixel pitch becomes smaller and the effects of leakage electric fields from adjacent pixels and changes in orientation become apparent. FIG. 2 is an enlarged view of a part of the spatial light modulator of the present invention as viewed from the front. One pixel 201
Are separated by a pixel separator 203, and an electric field is applied to the electro-optical medium of the pixel by a drive electrode 202. The operable electro-optical medium includes, for example, LiNbO3, a poled organic polymer film, an SmA liquid crystal, a nematic liquid crystal dispersed in a polymer, and a nematic liquid crystal.

Although the drive electrodes are formed on the same plane in FIGS. 1 and 2, they may have a quasi-planar structure in which an insulating layer is interposed between the electrodes.

Table 1 shows a more specific configuration employed in this embodiment.

[0041]

[Table 1]

An active matrix substrate using a Si wafer is described in Nikkei Electronics 1981, 2.1.
No. 6 p. 164, but the electrode arrangement corresponding to the pixel is different as shown in FIGS.

The pixel separator is SID96 DIGE
ST p. 611, a method of dissolving the photosensitive monomer in the liquid crystal and forming it by utilizing phase separation of the liquid crystal and the polymer, or a method of forming the monomer by directly exposing the monomer to UV light by mask exposure and photopolymerization. .

FIG. 3 shows an example of the pixel circuit configuration of the spatial light modulator employed in this embodiment. The transistor 301 has a source line 302, a gate line 303, and a drain connected to the transistor-side pixel electrode 304 and the auxiliary capacitor 305. The other pixel electrode 306 is connected to the common potential line 307. The potential of the common potential line is fixed at a substantially middle point of the source amplitude, and an electric field corresponding to a potential change of the transistor-side pixel electrode is applied to the electro-optical medium provided across the electrodes. Therefore, one pixel is an area indicated by 309. The basic drive is a thin film transistor (hereinafter, T
This is performed using an active matrix substrate using FT. LCD using active matrix substrate
Alternatively, it can be performed in the same manner as a matrix LCD in which MOS transistors are formed on a substrate.

As described above, a horizontal electric field generated in parallel between the electrodes or a vertical electric field generated in parallel on the electrodes (parallel to the paper) is applied to the electro-optical medium. An ECB mode or TN mode liquid crystal shown in Table 1 can be adopted as a typical electro-optical medium. Normally, in these liquid crystal modes, a vertical electric field generated between a common electrode provided opposite to a pixel electrode is used. In this embodiment, an electric field generated between at least two pixel electrodes on an active matrix substrate is used. Use. On the other hand, the influence of the orientation of the adjacent pixels is blocked by the pixel separator.

In FIG. 3, an initial alignment process is performed so that the liquid crystal becomes 308 on the active matrix substrate, and the director of the liquid crystal is twisted in a plane by a lateral electric field. The alignment treatment on the counter substrate side may be performed in an anti-parallel manner to 308 or a treatment perpendicular to the substrate.

FIG. 4 shows an example of a pixel circuit configuration in which the common potential line 407 is shared with electrodes on both sides. For simplicity, the auxiliary capacitance connected to the transistor drain is not shown. The pixel 409 straddles the electrode on the common potential side and the electrode on the transistor side. The basic operation is the same as in FIG.

FIG. 5 shows a configuration example of a pixel circuit using the gate line potential of the previous X pixel row without using the common potential line. For simplicity, the auxiliary capacitance connected to the transistor drain is not shown. The operation is the same as in FIG.

FIG. 6 shows an example of a structure in which all electrode potentials are controlled by transistors without using a common potential line. For simplicity, the auxiliary capacitance connected to the transistor drain is not shown. In the configurations of FIGS. 3, 4, and 5, the potential of the electrode paired with the transistor-side electrode is basically fixed, but in FIG. 6, all the electrodes are independently supplied with the potential. Since one pixel 609 is driven by a potential difference between the electrodes, the source signal at the time of driving includes a difference in data to be displayed. This will be described later.

FIG. 7 shows another configuration driven by a similar difference signal. In FIG. 6, one pixel is composed of two transistors and two electrodes, but in the configuration of FIG. 7, a part of adjacent pixel electrodes is physically divided by a pixel separator as a drive electrode. Therefore, one pixel is effectively one transistor and one electrode,
An advantage is that the number of transistors can be reduced by half compared to the configuration of FIG. In addition, since the transistor, the source wiring, the gate wiring, and the storage capacitor can be provided below the pixel separator, at the active matrix side, that is, at a position overlapping in a plane, a reduction in the pixel area ratio (opening ratio) can be suppressed. Further, there is an effect that the aperture ratio is not limited to the size of the electrode. Since the potential is the same as that of the adjacent pixel, there is also an advantage that the influence of the leakage electric field is small. Further, when the active matrix substrate is a transparent substrate on which a TFT is formed, a light-shielding layer covering a transistor, a source wiring, a gate wiring, and an auxiliary capacitance portion can be used as a self-alignment mask when forming a pixel separator.

FIG. 8 shows an example of a pixel circuit configuration in which an adjacent selection signal line (for example, a gate line corresponding to a pixel row which is the previous X line) is used as a ground destination of an auxiliary capacitor. That is, after the previous line is selected, the gate wiring of the previous line is often set to a fixed potential.

Next, a driving method using a difference potential used in FIGS. 6, 7 and 8 will be described.

FIG. 9 shows an example of a drive source line signal for giving a difference potential. The display data column 901 of a certain pixel row is ... 11
010010 ..., the drive source line signal 902, which is a signal line for sending display data, becomes .010011100... Corresponding to the difference potential of the display data sequence. Although a binary signal is given here as a drive signal for simplicity, a multivalued or analog signal can be handled since a difference may be calculated from a specific potential and given.

FIG. 10 shows an example in which the direction of an electric field can be added as information when a horizontal electric field is used. An electric field of three levels 0, +1 and -1 can be given according to the direction of the electric field. An arrow 1001 in the figure indicates the direction of the electric field. Liquid crystal modes that use the direction of an electric field include ferroelectric liquid crystals and antiferroelectric liquid crystals, which are suitable for driving these.

The drive for giving such a difference potential has a characteristic that the potential applied to the pixel is easily converted into an AC even in the case of a large painting or the like, and can prevent deterioration due to the application of a DC applied to the electro-optical medium.

Although the embodiments of the present invention have been described above, the present invention is applicable not only to the simple electrode shapes described in the embodiments, but also to various shapes such as a comb tooth shape and an orthogonal shape. In the present invention, the configuration of the pixel is divided not only by the electrode but also by a physical separating means, so that a finer pixel can be formed. In addition, it can be widely applied to optical information processing and display devices.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a spatial light modulator according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part of the spatial light modulator according to the embodiment of the present invention as viewed from the front.

FIG. 3 is a configuration diagram of a pixel circuit of the spatial light modulator according to the embodiment of the present invention.

FIG. 4 is a display pattern group that is reduced and projected according to the embodiment of the present invention.

FIG. 5 is a configuration diagram of another pixel circuit according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a pixel circuit configuration in which one pixel is configured by two transistors and two electrodes according to the embodiment of the present invention;

FIG. 7 is a configuration diagram of another pixel circuit driven by a difference signal according to the embodiment of the present invention.

FIG. 8 is a configuration diagram of a pixel circuit grounded to an adjacent selection signal line according to an embodiment of the present invention.

FIG. 9 is a schematic diagram of a driving method for giving a difference potential according to the embodiment of the present invention.

FIG. 10 is a schematic diagram of a driving method according to an embodiment of the present invention in which the direction of an electric field is given as information.

FIG. 11 is a plan view of the liquid crystal panel according to the embodiment of the present invention.

FIG. 12 is a diagram illustrating a cross-sectional view of a liquid crystal panel according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Switching element 102 Active matrix substrate 103 Substrate 104 Electro-optical medium 105 Pixel 106 Pixel separator 107 Drive electrode 201 1 pixel 202 Drive electrode 203 Pixel separator 301 Transistor 302 Source line 303 Gate line 304 Transistor pixel electrode 305 Storage capacitor 306 Common Potential line side pixel electrode 307, 407 Common potential line 308, 409 Initial alignment direction 309, 609 1 Pixel region 401, 501 Projected LCD pattern 901 Display data column 902 in a certain pixel row Driving source line signal 1001 Direction of electric field

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/336 F-term (Reference) 2H091 FA07X FA07Z FA50X FA50Z FD08 FD10 GA08 GA13 HA07 HA12 JA01 LA16 LA30 2H092 GA25 JA24 JB22 JB31 JB67 MA09 NA01 NA07 NA25 PA03 PA10 PA11 QA07 QA13 QA14 QA15 5C094 AA05 AA09 AA10 AA45 AA53 AA54 BA03 BA43 CA19 DB04 EA04 EA06 EA10 EB05 EC03 FA01 FA02 FB01 GA10 5F110 BB01 DD03 GG02 NN02

Claims (14)

[Claims] 2. An active matrix substrate comprising: a plurality of electrodes forming pixels; a switching element formed on each electrode; and the pixels being formed in a matrix. 2. The active matrix substrate according to claim 1, wherein a plurality of wirings are formed connected to the switching element, and a driving circuit is formed connected to each of the wirings. 3. An active matrix substrate in which one pixel region is formed by a plurality of electrodes, and a switching element is formed on at least one of the plurality of electrodes, and the active matrix substrate is disposed to face the active matrix substrate. In a spatial light modulator in which an electro-optical medium is sandwiched between a substrate and a separated substrate, a pixel separator for dividing a pixel region is formed in each pixel. 4. The spatial light modulator according to claim 3, wherein the plurality of electrodes are formed on the same plane. 5. The spatial light modulator according to claim 3, wherein the plurality of electrodes are formed on another layer with an insulating layer interposed therebetween. 6. The spatial light modulator according to claim 3, wherein the electrode has a reflection characteristic. 7. The spatial light modulator according to claim 3, wherein the electro-optical medium is a liquid crystal. 8. The spatial light modulator according to claim 3, wherein the pixel separator is a photopolymerized polymer. 9. The spatial light modulator according to claim 3, wherein the active matrix substrate is a silicon wafer on which a MOS transistor is formed. 10. The method according to claim 3, wherein
At least one of the electrodes constituting the pixel is connected to the switching element, and the other electrode is connected to a wiring having a specific potential. 11. The spatial light modulator according to claim 10, wherein an electrode connected to the wiring having the specific potential is connected to an adjacent selection signal line. 12. The spatial light modulator according to claim 3, wherein the switching element, the wiring, and the storage capacitor are provided so as to overlap the pixel separator. 13. The spatial light modulator according to claim 3, wherein the electrodes are connected to adjacent switching elements, respectively. 14. The space according to claim 13, wherein a drive signal for giving a signal corresponding to a potential difference between display data strings is given to a signal line for sending display data to a switching element to which said electrode is connected. Light modulation device.