JPS63212980A - Transmission type liquid crystal matrix display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-Y matrix in which unit picture elements are formed on a transparent substrate made of silicon, sapphire, glass, etc. The present invention relates to a transmissive liquid crystal matrix display device using an image display panel in which a liquid crystal is interposed between a transparent substrate and a liquid crystal substrate.

The above-mentioned transmission type liquid crystal matrix display device is publicly known, and includes:
Among those using a semiconductor switching element as a unit picture element, there are those using an MO3 type transistor and those using a thin film transistor (TPT) as the semiconductor switching element.

A conventional configuration using TPT is shown in FIG. Note that for convenience of explanation below, all similar parts are indicated by the same numbers, and each part has been appropriately enlarged, so the relative dimensions thereof do not necessarily correspond to the description in the main text. A unit pixel consists of Cd on a transparent substrate (not shown) such as a transparent glass plate.
TFT1' made by vapor depositing Se, CdTe, etc.
, 1' and a transparent display electrode (
(not shown), gate signal storage capacitor 2, and wiring X
i, Yj, Yj', etc., and a transparent substrate such as a glass plate with a transparent electrode attached to one surface (not shown)
A liquid crystal cell 3 is interposed between the two. For example, now
When a scanning gate signal is applied to the electrode wiring, that is, the gate wiring x1, the TFT1' is turned on, and the video signal passes from the Y electrode wiring, that is, the video signal wiring Yj, and charges the capacitor 2 through the TFT1'. The charge in the capacitor 2 corresponding to the amplitude of this video signal applies a gate voltage to the TFT 1', and in accordance with this voltage, an alternating current flows from the wiring Y' to the liquid crystal cell 3 via the TFT 1'. operates to modulate the external light that passes through this panel.

For example, if a dynamic scattering type liquid crystal is used as the liquid crystal, the transmitted external light undergoes dynamic scattering depending on the video signal. In addition, a vapor deposited film such as silicon oxide is formed on transparent electrodes and integrated substrates, and a homogeneous alignment process is applied to these films. Twisted nematic liquid crystal is used, and a polarizing plate with orthogonal axes is added to the display panel. In the case where the optical fiber is provided in the optical fiber, the orientation changes according to the video signal, and the transmitted external light can be modulated by the electric field effect.

FIG. 2 shows an example of a conventional configuration using MO3 type transistors. A unit picture element consists of an integrated substrate in which an MO3 type transistor 1°, a transparent charge storage capacitor 2, etc. are integrated on a transparent substrate such as sapphire, and a transparent substrate having a transparent electrode. This is an interposed liquid crystal cell 3.

For example, if a gate signal is applied to the gate wiring Xi now, the MO
The type 3 transistor 1 is turned on, and the video signal passes through the transistor 1 from the video signal wiring Yj and charges the capacitor 2. Even if the gate signal disappears, as long as the charge stored in the capacitor 2 is applying a voltage to the liquid crystal cell 3, the liquid crystal cell 3 will undergo phase transition, dynamic scattering, or electric field depending on the liquid crystal composition depending on the voltage. The effect causes a change in orientation, and the transmitted light continues to be modulated in response to the video signal voltage.

Therefore, as illustrated in FIGS. 1 and 2, it is possible to configure a television receiver by arranging unit picture elements in a matrix and scanning them in the X and Y directions. A group of transistors is turned on all at once in the X direction to write a video signal into a group of capacitors, and scanning is performed sequentially in the Y direction. C by so-called line scanning
The same effect as RT can be obtained, and a transmissive flat panel television is constructed.

Furthermore, in the transmissive liquid crystal display device according to the present invention, as illustrated in FIG. By installing it on a substrate, a translucent integrated substrate, etc., a color flat panel television can be constructed.

FIG. 3 shows a cross-sectional view of the unit picture element shown in FIG. 2 which is integrated into an integrated circuit. In this case, an aluminum film (with silicon as a semiconductor) is placed on a transparent substrate 17 made of a sapphire substrate.
A transmissive liquid crystal matrix display device incorporating O8 type transistors will be described, but the material of the conductive paths other than the transparent electrodes does not matter, so polycrystalline silicon may be used. Transistor 1 has a drain or source 4. Channel part 5. source or drain 6
The aluminum gate 7 forms the aforementioned gate wiring x1. 8 is a gate oxide film, and 9 is a silicon oxide film for protecting the surface of the transistor. 1o is a silicon oxide insulating film that covers areas other than picture elements. Reference numeral 12 denotes a transparent insulating film also made of silicon oxide, which forms the capacitor 2 together with transparent electrodes 11 and 13. The transparent electrode 13 is a capacitor electrode, and also serves as a display electrode that supplies a required signal voltage to the liquid crystal. Aluminum track 4&.

6a forms the aforementioned video signal wiring Yj, and the aluminum line 4 & connects the drain or source 4 with the aluminum line 6a.
are in electrical contact with the source or drain 6 and the transparent display electrode 13, respectively. transparent electrode 11
The transparent display electrode 13 is deposited by depositing a transparent conductive film such as a mixture of In203 and 5n02 or In2O3. 16 is a transparent substrate such as a glass plate; 16 is a transparent electrode such as an Xn205 film deposited thereon; these form a transparent electrode plate 21; 14 is a liquid crystal, and an integrated circuit board '2 is formed with an integrated circuit on the sapphire substrate 17 mentioned above.
0, and a transparent electrode plate 2. The liquid crystal cell 3 is filled with the transparent electrode 6, and together with the transparent display electrode 13, constitutes the liquid crystal cell 3.

R and G are three primary color filters such as red and green deposited on the sapphire substrate 17 corresponding to the unit picture elements.

Performs color selection of transmitted light. As the liquid crystal 14, a dynamic scattering type can be used. In this case 11-13
Dynamic scattering is caused in the liquid crystal 14 according to the accumulated charge of the capacitor consisting of, and the light intensity of the transmitted chromatic light L2 is controlled. However, in order to construct a good transmission type liquid crystal matrix display device, it is desirable to operate the liquid crystal 14 in a twisted nematic (TN) type. In this case, the transparent electrodes 13 and 15 are aligned so that they are homogeneously aligned at right angles to each other, and two polarizing plates 18 are placed on the transparent electrodes 13 and 15 as shown in the figure.
．． Constitute by sandwiching 19.

At this time, the orientation of the liquid crystal 14 changes according to the accumulated charge of the capacitors 11 to 13, and the light intensity of the transmitted chromatic light L2 can be controlled. Also, if necessary, electrode 13.15
An insulating film such as a silicon oxide film may be deposited on the surface, and the surface may be subjected to orientation treatment.

At this time, AC operation is performed, and the circuit configuration shown in FIG. 1 is useful.

In the configuration of a television display device, for example, about 240 unit picture elements as shown in FIG. 3 are arranged in a matrix in each of the X and Y directions as shown in FIG. The size of a unit pixel is, for example, 150 microns in the X direction and 2 microns in the Y direction.
00 microns Therefore, the effective screen size is about 36x48-. Since this type of liquid crystal display device can be driven at low voltage with low power consumption, it is considered to be useful as a battery-operated television of the multiple type.

However, this type of transmissive liquid crystal matrix display device has several problems that need to be solved.

One of them is the problem of the transmitted light source that illuminates the display panel. In order to reduce power consumption, it is necessary to effectively utilize external light such as sunlight. The second problem is color display.

An additive color method is used for color display, and a vortex-forming operation is indispensable, but unless white display can be achieved well, clear color display is impossible.

Furthermore, there is a need for a sufficient and efficient light source and light transmission mechanism for use at night, and there is also a strong demand for televisions and the like that use liquid crystals to be thinner, smaller, and easier to use.

In view of the above, the present invention provides a transmissive liquid crystal matrix display device with low power consumption, which can easily solve all of the above problems using a useful external light illumination method.

The present invention provides a transmissive liquid crystal display device that uses a transmissive liquid crystal panel, a housing, and a unique optical auxiliary plate, and is constructed by adding special ideas to the combination structure of these.

An embodiment of the present invention will be described below based on the drawings. Fourth
The figure is a schematic vertical cross-sectional structural diagram of a transmissive liquid crystal display device used in the present invention when using external light. In FIG. 4, a transmission type liquid crystal display panel 23
A TN type liquid crystal 14 is interposed between an integrated substrate 20 and a translucent electric sign board 21, and three primary color filters of R, G, and B are installed on the integrated substrate 20 in correspondence with picture elements. , polarizing plates 18 and 19 are arranged to sandwich these.

The observation area is located, for example, on the outside of the display panel 23 on the translucent electrode plate 21 side, and the display panel 23 has a light auxiliary device on the integrated substrate 2o side that can be opened and closed at an acute angle θ with respect to the display panel 23. A board 24 is installed. The light auxiliary plate 24 can have at least the surface 26 facing the integrated substrate 20 as a white light scattering surface, and can be held by the plate-like support 26 . The light scattering surface 25 can be formed, for example, by coating or spraying a white pigment such as white powder of titanium oxide or magnesium oxide on its surface, or by forming it from white paper or the like. Alternatively, a directional white scattering surface can be formed by applying an aluminum foil or the like having irregularities.

Furthermore, 25 and 26 can be integrated and made of plastic or the like. The light auxiliary plate 24 is seen through from the observation point via the display panel 23.

Let us now consider the case where the display panel 23 is supplied with the necessary signal voltage as described above and is operated. In the presence of normal sunlight or indoor lighting, these external lights L1 enter the light auxiliary plate 24 through a gap with the display panel 23 that opens upward, and generate white scattered light LR on the light scattering surface 25. do. When the number display panel 23 is in a transparent state, the observer can see through the light auxiliary plate 24 through the display panel 23, and a white transparent display can be performed by the light scattering surface 26 exhibiting white color.

This white display determines the brightness and color clarity in color display. Therefore, in order to make this white display bright and transparently display a color image at an appropriate viewing angle, the light auxiliary plate 2
The inclination angle θ of 4 is an important factor. The available tilt angles range from 30 to 800 acute angles, with the most preferred θ being 40 to 800.
It is in the range of 6oO.

The light auxiliary plate 24 is obliquely seen through the display panel 23, and the white display must be projected to include the entire effective screen of the display panel 23, so the screen of the light auxiliary plate 24 is visible through the display panel 23. It must be large both vertically and horizontally relative to the effective screen, and must be made to have a suitably wide area. If the inclination angle O is an obtuse angle, the light auxiliary plate 24 has an extremely large screen, and it is necessary to see through the display panel 23 from a considerably oblique direction. Compared to the case of viewing perpendicular to the surface, the perspective image becomes extremely vertically packed, or it becomes impossible to see through. On the other hand, when θ is zero, external light cannot enter the light auxiliary plate 24.

If the inclination angle θ is selected within the range described above, external light will appear.

irradiates the light scattering surface 25 appropriately, a bright white display can be performed, and moreover, it can be seen through as a natural screen shape at an appropriate viewing angle. Therefore, when a color video signal is supplied to the display panel 23, the signals are R and G.

The transmittance of the liquid crystal 14 in the portion corresponding to B changes, and a good color image including white is transparently displayed.

In order to further improve the brightness, it is also possible to impart translucency to the light auxiliary plate 24, and to use transmitted scattered light LT using external light, '' on the back surface of the light auxiliary plate 24, in addition to the scattered light L8. Useful. According to this method, in the above configuration, the effective amount of incident light from the outside changes depending on the size of the inclination angle θ, and the amount of scattered light changes.

In other words, while the brightness of the screen changes, the brightness of the surrounding external light and transmitted/scattered light can be set almost independently of θ, so there is no need to attach an illumination light source. A low-power display device can be constructed. In addition, when the ambient light is not sufficiently bright, such as at night, it also has the advantage of allowing irradiation from the back side of the light auxiliary plate 24 by auxiliary irradiation.

To make the light auxiliary plate 24 transparent, even if the support plate 26 is made of a transparent plate made of plastic or the like and the light scattering surface 26 is made semitransparent, the entire light auxiliary plate 24 is made of a milky white semitransparent plate made of plastic or the like. may be configured.

In order to further improve the utilization rate of external light, not only this example but also all the light auxiliary plates described in this specification may be made into a spherical or interfering surface shape so as to be concave with respect to the display panel. can. This configuration has the advantage that a brighter image can be obtained because L, , L have the directionality of condensing light and directing it toward the display panel.

Although the above description has mainly been about display panels for color images, the present invention can be similarly applied to monochrome display panels that do not have color filters B, G, and R, allowing good black and white images to be seen through.

FIG. 6 is a diagram showing a vertical cross-sectional structure of an embodiment of a transmission type liquid crystal matrix display device according to the present invention.

In FIG. 5, 23 is the above-mentioned transmissive liquid crystal display panel, and 24 is an optical auxiliary plate installed on the display panel 23 at an acute angle of inclination O so that it can be opened and closed. At the same time, the light auxiliary plate 24 has white scattering and diffusion properties against external light.
By maintaining the light diffusion and transmission illumination effect, transparent display can be performed even when the ambient light is dark, such as at night. Reference numeral 26 denotes a light scattering surface which forms a white scattering surface against external light, is semi-transparent, and is configured to diffusely transmit the irradiated light Li from the auxiliary light source 38.

26 is a transparent body such as plastic that holds the light scattering surface 36. A light reflector 37 is provided to cover the outer surface of the transparent plate 36, and is made of a cumulative layer with a changed refractive index, aluminum foil, a vapor deposited film, or the like. The auxiliary light source 38 may be provided with one or more auxiliary light sources 38 at the intermediate or edge portions of the light auxiliary plate 34 by means of a light reflector 37 to direct the irradiation light to the transparent body 2.
It is installed so as to invade 6. Therefore, the irradiated light Li from the auxiliary light source 38 is diffusely reflected in the transparent body 26 by the action of the light scattering surface 26° and the light reflector 37, and almost uniformly bright diffuse transmitted light is transmitted over the entire surface of the semitransparent light scattering surface 26. L, /
can be generated. Therefore, high-intensity ambient light L1
When the brightness of the surrounding light or the scattered light is insufficient, the diffused transmitted light L from the auxiliary light source 38 forms a bright white display surface and provides a good contrast ratio through the display panel 23. Color or monochrome images can be observed.

Further, when the auxiliary plate 26 is closed at night, a uniform and sufficient light beam can be efficiently incident on the entire surface of the panel 23, which is extremely effective for clear color display.

FIG. 6 is a structural external view of an embodiment of a transmissive liquid crystal display device according to the present invention, and shows an example in which an image display device such as a television receiver is configured. 4o is a flat plate-shaped case, and the display panel 23 is housed at approximately the center or lower than the center. The window portions 41 and 41' are arranged on the front and back sides of the housing 40 corresponding to the position of the display panel 23 so as to include at least the effective screen of the display panel 23. 24 are arranged. The end portion of the light auxiliary plate 24 is connected to the lower part of the display panel 23 via a connecting fitting 42 so that it can be opened and closed.

This optical auxiliary plate 24 forms the back cover of the case 40, and is designed so that the inclination angle, that is, the opening/closing angle O can be set to at least an acute angle. Further, the optical auxiliary plate 24 also serves as a mounting and fixing base for the housing 40 in the operating state as shown in the figure. The housing 40 also includes an antenna 43 for receiving television radio waves.
Necessary adjustment parts such as a volume adjustment polyurethane 442 with a built-in power switch, a channel selection dial 45, and a speaker section 46 are provided. Further, inside the case 40, there is a chainer, a video intermediate frequency amplification circuit, and a video detection amplification circuit.

It accommodates circuit blocks such as an audio detection amplifier circuit, a control signal generation circuit, and an X driver for driving the display panel 23.

When the light auxiliary plate 24 shown in Figs. 4 and 6 is used as the light auxiliary plate, and the light auxiliary plate 24, which serves as the back cover and installation fixing stand, is opened so that the angle of inclination θ becomes an acute angle, Scattered light LR1 and further transmitted scattered light.

Due to the diffused transmitted light, a good color image can be seen through the display panel 23.

Such a configuration has several notable advantages. That is, the first method is to distribute the necessary parts vertically and install the display panel 23 in the center of the case 40 or lower than the center, so that the light auxiliary plate 24 or 34, which also serves as the back cover, can be used as a display panel. Compared to the effective screen of No. 23, the area can be made sufficiently large, especially in the direction of oblique perspective, and it is possible to expand the viewing angle range that can be seen through and improve image distortion due to oblique perspective. Second, since it is integrally connected to the housing 40 via the connecting fitting 42 so that it can be opened and closed, the device can be made smaller, that is, pocket-sized. This is extremely effective in improving the usability of this type of device.

Note that the optical auxiliary plate section 0, where the volume adjustment volume 44 and the channel selection dial 46 are located, is not necessarily required because it cannot be seen through. Therefore, this portion of the light auxiliary plate 24 may be removed or the light scattering surface portion may be removed to form a light scattering surface 25 that can be observed through transmission only upward from this portion.

FIG. 7 is an external view of still another embodiment of the transmission type liquid crystal matrix display device according to the present invention. In this embodiment, unlike FIG. 6, the optical auxiliary plate 24 includes the effective screen of the display panel 23, and is limited to a portion necessary for perspective observation. That is, the optical auxiliary plate 24 is connected to the casing 6o near the lower end of the back window portion 51' via a connecting fitting 52 so as to be openable and fixed, and also serves as a part of the back cover. If necessary, the optical auxiliary plate 24 may be provided with legs 57 that can be opened and closed as shown in the drawings to support the casing 5o during transparent observation. In this case, a more compact and robust television device can be realized.

Although the embodiment has been described using an MO3 type transistor as an example, it is clear that the same implementation can be performed using a TFT system or the like.

As described above, according to the present invention, a light auxiliary plate having a light-scattering surface is connected to the casing housing the transmissive liquid crystal matrix panel so as to be openable and fixed, and the external light is effectively used to provide clear images. In addition to making it possible to display a wide variety of colors, the auxiliary plate can be opened and used as a support only when using external light. At night, by closing the auxiliary plate that also serves as the back cover of the case, the built-in light source can illuminate the entire display panel with uniform and sufficient light, making it possible to display clear colors while also being thin and compact. A display device that is small and extremely easy to use is realized.

[Brief explanation of the drawing]

Figures 1 and 2 are the circuit diagrams of the IJ sock display device; Figure 3 is the transmission type liquid crystal display shown in Figure 2)
FIG. 4 is a schematic cross-sectional structure diagram of an embodiment of a transmission type matrix display device according to the present invention, FIG. 5 is a cross-sectional structure diagram of the same embodiment, and FIGS. Each figure is an external view of the configuration of the embodiment. 1.1', 1'...field effect transistor, 2
...Capacitor, 3,14...Liquid crystal,
13...Transparent display electrode, 15...Transparent electrode, 16...Transparent substrate, 17...
Transparent substrate, 18.19...Polarizing plate. 2Q... Integrated substrate, 21... Transparent electrode plate, 23... Display panel, 24...
Light auxiliary plate, 25...Light scattering surface, 36...
・Transparent body, 37...Light reflector, 38...
・Auxiliary light source, 40.60... Housing, 42°52
...... Connection fittings, R, G, B... Color filter, Xi, Xi+, -------X electrode arrangement M,
Yl, Y:l' j:l-4-1+++...Y electrode wiring, θ......tilt angle. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure-~ sect sect 〒 ×

Claims (1)

[Claims] A transparent X, Y device in which a large number of unit picture elements each including at least a transparent display electrode are arranged in both the X and Y directions on a transparent substrate.
An image display panel is formed by interposing a liquid crystal between a matrix substrate and a transparent substrate with a transparent electrode attached to one surface, and an operating signal voltage is selectively applied between the display electrode and the transparent electrode. a transmissive liquid crystal matrix display unit configured to supply a liquid crystal, selectively operate the liquid crystal, and modulate and control external light transmitted through the image display panel; A light auxiliary plate that can be inclined at an acute angle and whose surface forms a light scattering surface is installed, and external light enters the light auxiliary plate through an acute gap between the light auxiliary plate and the display panel. The light scattering surface of the light auxiliary plate is configured so that the scattered light of the external light of the light auxiliary plate can be seen through the display panel from the other side of the display panel, and the light scattering surface of the light auxiliary plate is configured to have a diffused The light auxiliary plate is imparted with transparency, and has a light reflector on a surface opposite to the light scattering surface of the light auxiliary plate, and the light reflector allows irradiation light to be directed to the light scattering surface at the middle or edge portion of the auxiliary plate. It has one or more auxiliary light sources installed so as to penetrate the display panel, and allows diffused transmitted light from the auxiliary light sources through the light scattering surface to be seen through the display panel, as well as scattered light due to external light. The display panel has a color filter corresponding to a unit picture element, the display panel is housed in a case together with a circuit block for driving the display panel, and the front and back positions of the case are arranged in correspondence with the display panel. Of the windows formed in the window, at least the back side window is covered,
and the optical auxiliary plate is connected to the housing at an acute angle so as to be openable and fixed, and the optical auxiliary plate forms part or all of the back cover of the housing and serves as a support for the housing when opened. Transmissive liquid crystal matrix display device with special features.