JP2873584B2 - Image display device and driving method thereof - Google Patents

Description

The present invention relates to an image display device having a large screen and a high-definition image.

[Conventional technology]

2. Description of the Related Art In recent years, an image is formed and displayed by moving (scanning) a projection position of a light beam having information of red, green, and blue with respect to a white screen in a passenger aircraft or a general room. .

In addition, a large screen is obtained by enlarging and projecting the CRT screen with a reflecting mirror.

More recently, a large screen has been obtained by enlarging and projecting a liquid crystal display device having a plurality of matrix electrodes by a lens system. Further, as the liquid crystal display device,
A type with a thin film semiconductor active device (TFT) in each pixel,
A type using a ferroelectric liquid crystal display device and the like have been proposed.

By the way, as a conventional driving method of a liquid crystal display device, for example, in the case of a display device using a ferroelectric liquid crystal having a plurality of matrix electrodes, a two-field method or a four-pulse method is used.

In the two-field method, as shown in FIG. 5, the selection time of one scanning electrode is composed of four phases, one frame for one screen display is divided into two, and the two fields of the first half and the second half are divided into two. In some cases, two phases are arranged, and black writing and white writing are performed in different fields.

Here, "the selection time is composed of four phases"
This means that there are four pulses within the selection time of one scan electrode in one frame.

Also in the four-pulse method, as shown in FIG. 6, the selection time of the scanning electrode is divided into four, and the direction of the spontaneous polarization of the ferroelectric liquid crystal molecules is inverted or held to display white and black. .

[Problems of conventional technology]

However, in the type in which the CRT screen is enlarged and projected by the reflecting mirror, there is a limit in improving the brightness of the CRT screen, and therefore, there is a problem that the entire screen becomes very dark.

In addition, a type in which an arbitrary screen is formed by applying gradation information to a light beam (beam) composed of the three primary colors of light, red, green, and blue, and moving the light beam at high speed, limits the miniaturization of the light beam. And not suitable for high definition images. Since the means for moving the light beam at high speed is complicated, the production cost is increased.

Of the types that magnify and project a liquid crystal display with multiple x multiple matrix electrodes with a lens system, the type that uses a TFT requires a complicated process to fabricate the TFT that is a component, and therefore costs are low. Mimics a rise. In the type using a ferroelectric liquid crystal, although the cost of manufacturing a panel is low, gradation display cannot be performed when a matrix is formed due to the physical properties of the ferroelectric liquid crystal. Further, since the distance between the substrates of the device is as small as about 2 μm, an electrical short-circuit easily occurs between a pair of electrodes constituting the pixel, and the yield is reduced. Therefore, one device must be configured with a small area.

Further, regarding the driving method, the two-field method described above,
In the four-pulse method, the time during which the ferroelectric liquid crystal molecules are effectively moved is one of the four pulses existing within the selection time. Therefore, if a display device having a 3000 × 3000 matrix electrode is to be displayed 30 times per second, the ferroelectric liquid crystal molecules are (3000 × 30 × 4) ⁻¹ = 2.7.
It must respond with a microsecond pulse. There is no problem if a very high voltage can be applied to the ferroelectric liquid crystal, but since the withstand voltage of the normal IC currently used is about ± 20 V,
The above-mentioned display cannot be performed because the ferroelectric liquid crystal which has been developed to date does not respond at all with a pulse of 2.7 μsec.

As described above in the case of a display device using a ferroelectric liquid crystal, in the case of a TN type liquid crystal display device, the conventional driving method does not have a characteristic that the liquid crystal responds with only one pulse, and the scanning electrode When the number is large, the contrast of the TN type liquid crystal display device becomes small, so that the display cannot be performed substantially.

An object of the present invention is to solve the various problems in the various methods for obtaining a conventional large screen and obtain a large screen by a simple method.

[Means for solving the problem]

Therefore, the present invention relates to a first substrate including a plurality of electrodes formed of a transparent conductive film over a light-transmitting substrate, a first substrate including conductive leads, and a single electrode and a lead formed over the transparent substrate. With the electrodes on the first substrate and the electrodes on the second substrate so that the electrodes on the second substrate cross each other at substantially right angles, and a ferroelectric substance is A liquid crystal device having a liquid crystal exhibiting a crystalline liquid crystal and a means for aligning liquid crystal molecules in an arbitrary direction is prepared. In other words, the liquid crystal device is composed of a single liquid crystal device composed of a plurality of dots and a liquid crystal device that displays a screen composed of a plurality of dots that is originally composed of a plurality of plural dots. Then, a light source is placed in a direction perpendicular to the substrate surface of the liquid crystal device, light from the light source is made incident on the liquid crystal display device, and display light obtained by passing through the liquid crystal device is irradiated on a means for reflecting or refracting the display light. Such an image display device.

For example, when a display of 3000 × 3000 pixels is to be obtained as an image, a liquid crystal device having 1 × 3000 dots is used. In order to display one screen, by continuously changing the angle of the means for reflecting or refracting light in synchronization with the display of one row, the reflected display of one row is sequentially displayed.
By moving the projection position 3000 times and projecting on the screen, one screen is composed.

The focus and the size of the screen are determined by adjusting the positional relationship between the screen, the liquid crystal device, and the light source.

In the present invention, since a matrix is composed of a single dot × a plurality of dots, a signal can be composed of a pulse having one phase for one piece of information required per dot.
In addition, since the matrix is a 1 × 3000 dot matrix, the amount of rotation of liquid crystal molecules can be controlled by the pulse height.

The means for reflecting or refracting reflects or refracts the display from the liquid crystal device and projects it on the screen.In synchronization with the movement of the display of the liquid crystal device, the direction of reflection or refraction is changed, and a linear light beam is used. It has a function of converting a certain display into a planar display, that is, an image display.

With the above-described configuration, the same display as displayed on a plurality of matrix liquid crystal devices can be displayed on a single liquid crystal device.

A feature of the present invention in terms of a driving method is that the above-described device has only one pulse within a time for driving the liquid crystal molecules as an electric field applied to the liquid crystal molecules.

Here, "within the time for driving liquid crystal molecules" will be described in comparison with the conventional technique. In the two-field method described above, "within the time for driving liquid crystal molecules" means "within a portion where a certain liquid crystal molecule exists". Within the time during which the scanning electrode included in the pixel is selected ".

In the two-field method, four pulses existed during the time when one scanning electrode was selected, that is, during the time when the liquid crystal molecules were driven.

 Hereinafter, the present invention will be described with reference to examples.

Embodiment 1 First, an outline of a liquid crystal device used in the image display device of the present invention is shown in FIG.

In the liquid crystal device (1), an ITO film was formed on a 1.1 mm-thick soda lime glass prepared as follows by sputtering a 1500 mm thick ITO film.
Form a film. By a known patterning method, 2000 electrodes and leads (2) were produced, and used as a first substrate (3). In a similar manner, a second substrate (5) having one electrode and a lead (4) was obtained. A polyimide precursor solution (NMP solvent) was sprayed on the second substrate by an offset method, and baked at 250 ° C. for 1 hour in N ₂ gas to obtain 200 ° C.
Was obtained. This film was micro-scratched in a certain direction by a known rubbing method. Thereafter, the first and second substrates were adhered to each other with an epoxy-based adhesive through particles having a diameter of 2.5 μm. Then, ferroelectric liquid crystal is injected by a well-known vacuum method, and then the injection port is
Sealed with resin.

 Thus, a liquid crystal device (1) is obtained.

Next, FIG. 2 shows a schematic diagram of the image display device of the present embodiment.

The image display device of the present embodiment comprises a light source (6), a liquid crystal device (1), a polarizing plate (7), means for reflecting light from the liquid crystal device (8), and a screen (9) with enlarged display.
And an optical system composed of a lens (10) for projecting the light to the projector.

The display light from the liquid crystal device (1) passes through a polarizing plate (7), passes through a means (8) for reflection, and is reflected there and reaches a screen (9) enlarged by a lens (10).

A cold cathode tube was used as the light source (6). The polarizing plate (7) was attached to both outer surfaces of the liquid crystal display device. The reflecting means (8) is a cylindrical polygonal mirror having 30 surfaces. However, the drawings are shown by circles. The reason why the number of screens is 30 is to consider that one screen is formed by rotating the cylindrical polygon mirror once per second, and 30 screens are displayed per second. Therefore, by determining the number of screens to be displayed in one second, the number of surfaces of the polygon mirror is determined. The polygon mirror is rotated by 6 × 10 ⁻³ deg each time a synchronization pulse is applied once by a combination of a stepping motor and a gear. The synchronization pulse is generated at the same time when the display of the liquid crystal device changes. That is, the polygon mirror is 6 × corresponding to one display of the liquid crystal display device.
By rotating by 10 ⁻³ deg, the position of the projected image projected on the screen corresponding to one display moves, and one screen can be created on the screen.

The display light from the liquid crystal device enters one surface of the polygon mirror, is reflected there, and is projected on the screen (9).

When the projection of one screen ends on one surface, the projection of the second screen starts on the next surface. In this way, the projection is performed sequentially, and a continuous screen is displayed on the screen.

The lens for enlarging the image because of the need to project it on the screen was placed at the position where the light reflected by the polygon mirror was incident.
It is effective to use the lens as a zoom lens to continuously change the magnification of the projected image, since the size of the screen and the distance between the screen and the image display device can be arbitrarily selected.

FIG. 7 shows a block diagram of the drive circuit in this embodiment.

The data signal sent to the shift register (24) is sent as a synchronization pulse to the motor driver (25) and further sent to the analog selector (26).

The drive voltage level is sent to the analog selector (26), and the signal shown in FIG. 8 (b) is sent to the segment side electrode (22).

A signal shown in FIG. 8A is sent from the power supply (27) to the common-side electrode (28).

As a result, an electric field is applied to the pixel (29), and as a result, the light transmittance of the pixel (29) changes as shown in FIG. 8 (c).

FIG. 8C shows that the transmittance changes in response to the liquid crystal molecules responding to the individual pulses. Then, gradation display could be performed.

In this embodiment, a mirror is used as a means for reflecting display light, but it can reflect incident light to form one screen alone,
In addition, after the projection of one screen is completed, any one can be arbitrarily selected without being locked by a mirror as long as the display light constituting the next screen can be incident.

As described above, according to the present invention, a large screen can be obtained by a small image display device, and a large screen can be configured by a liquid crystal device having a single electrode × a plurality of electrodes. Since there is no need to make it, the production is easy and the production yield is improved.

Embodiment 2 The outline of the image display device of this embodiment is, as shown in FIG. 3, composed of a light source (6), a polarizing plate (7), a liquid crystal device (1) and a plurality of prisms surrounding them. It consists of arranged polyhedra (11). However, the prism is omitted.

The display light from the liquid crystal device (1) produced in the same manner as in the first embodiment is refracted by a prism, then enlarged through a lens (10), and projected on a screen (9). The number of prisms is selected according to the number of screens to be projected per second when the polyhedron is rotated once per second. For example, when 30 screens are projected in one second, the polyhedron is a 30-plane having 30 prisms, and the polyhedron rotates each time a synchronization pulse is applied once by a combination of a stepping motor and a gear. As a result, the angle at which the display light is incident on the prism changes, so that the position of the projected image projected on the screen moves and one screen can be created on the screen. At this time, it is necessary to adjust the refractive index of the prism and the overall size of the prism so that one screen is formed by one prism, and when the projection of one screen is completed, the display light is incident on the next prism. There is.

In this embodiment, a prism is used as a means for refracting the display light, but the incident light can be refracted to form one screen by itself, and when the projection of one screen is completed, the display light constituting the next screen is formed. The prism is not limited to a prism as long as it can be made incident.

Also in the case of the present embodiment, it is effective to use a zoom lens as the lens as in the first embodiment.

As described above, according to the present invention, a large screen can be obtained by a small image display device, and a large screen can be formed by a liquid crystal device having a single electrode × a plurality of electrodes. Since there is no need to make it, the production is easy and the production yield is improved.

Third Embodiment In the present embodiment, an image display device for displaying a stereoscopic image on a screen using two optical systems in the image display device shown in the first or second embodiment.

In this embodiment, as shown in FIG. 4, two optical systems of the device shown in the first embodiment are used in the image display apparatus to form a left-eye screen and a right-eye screen, respectively, so that the optical system is formed in advance. Set. In the optical system for the left eye, a polarizing plate (12) for displaying the image for the left eye is arranged in the device, and in the optical system for the right eye, the image for the right eye is also displayed in the device. Polarizing plate (13) is arranged in advance. These polarizers are used in liquid crystal display devices (1)
Performs the same function as the function provided on the upper surface of the device. The polarizing plates (12) and (13) for the left and right eyes were arranged so that the polarizing axes were orthogonal to each other. (14) are observation glasses for observing the screen projected on the screen, and are polarized in the same direction as the left-eye polarizing plate (12) and the right-eye polarizing plate (13) in the image display device. Two polarizing plates with axes (1
5) (16) is incorporated for the left eye and right eye, respectively.

Here, the liquid crystal devices provided in the optical systems for the left eye and the right eye are made to display the images prepared for the left eye and the right eye, respectively, and the left and right images projected on the screen (9) are displayed. By observing the right-eye projection image through the glasses (14), it is felt that a stereoscopic image appears in front of the observer.

Here, the polarizing plate for the left eye (12) and the polarizing plate for eyeglasses (15)
Are in the same direction, the polarizing axes of the right eye polarizing plate (13) and the eyeglass polarizing plate (16) are in the same direction, and the polarizing plates (12) (15) and the polarizing plate (13) Since the polarization axes of (16) are orthogonal to each other, the projection image viewed by the left eye and the projection image viewed by the right eye are separately projected on the left and right eyes.

In the present embodiment, the polarizing plate is used for the glasses, but the liquid crystal shutter is used instead of the polarizing plate. When the shutter is opened, the image for the right eye is sent to the observer's brain, and the left and right images are combined, so that it appears as if a stereoscopic image appears in front of the observer.

According to this embodiment, a large screen can be obtained by a small image display device, and a large screen can be formed by a liquid crystal device having a single electrode × a plurality of electrodes. In the past, a stereoscopic image that could not be obtained unless the conventional method of projecting a large screen image double or two screens separately had a single x multiple electrodes The use of two sets of liquid crystal devices has a major feature that a large-screen stereoscopic image can be easily obtained.

[Effects] A liquid crystal device using a matrix composed of a singular × plurality has an elongated shape, and the area can be reduced by using a liquid crystal device having a plural × plurality of matrices. As a result, a large number of liquid crystals could be obtained from one substrate. It was also advantageous in terms of yield, and was able to reduce costs.

In addition, the present invention has an advantage that the configuration is simple because most of the conventional CRT technology can be used.

Displaying a movie requires 30 screens per second.
According to the present invention, one dot information can be displayed by a signal consisting of one pulse. For example, a 3000 × 3000 pixel required for a high-definition TV can be displayed in a ferroelectric mode. The response speed of the crystalline liquid crystal material is about 10 μsec.

In a ferroelectric liquid crystal display of a plurality of dots and a plurality of dots, a gradation display, which was impossible, has been made possible. When the pulse width of the liquid crystal molecules was constant, the degree of rotation of the molecules could be adjusted by the pulse height, and gradation display was possible.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a liquid crystal device used in the present invention. 2 to 4 are views schematically showing an image display device of the present invention. 5 and 6 are diagrams showing driving waves of a conventional ferroelectric liquid crystal display device. FIG. 7 shows a block diagram of the drive circuit. FIG. 8 is a diagram showing drive signals. DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device 2, 4 ... Electrode and lead 3 ... 1st board | substrate 5 ... 2nd board | substrate 6 ... Light source 7 ... Polarizing plate 8 ... Means for reflecting 9 ... Screen 10 ... ... Lens 22 ... Segment side electrode 24 ... Shift register 25 ... Motor driver 26 ... Analog selector 28 ... Common side electrode

Claims (3)

(57) [Claims] 1. A liquid crystal device having a ferroelectric liquid crystal or liquid crystal molecule between a first substrate having a plurality of electrodes connected to leads and a second substrate having electrodes connected to the leads. And a light source and display light from a light source that has passed through the liquid crystal device is reflected or refracted by one surface and projected onto a screen, and the one surface is synchronized with a display movement that is a linear light beam of the liquid crystal device. By rotating in one direction, the position of the display light projected on the screen is moved to form one screen, and when the one screen is completed, it appears by rotating in one direction. An image display device, wherein another surface adjacent to the one surface has a rotating polyhedron for reflecting or refracting the display light for forming the next one screen. 2. The polarizing plate according to claim 1, wherein the liquid crystal display device, the light source, the rotating polyhedron, and the light source side and the opposite side of the light source with the liquid crystal device interposed therebetween. Having two sets of optical systems for the left eye and the right eye, wherein the polarizing axes of the polarizing plate for the left eye and the polarizing plate for the right eye are orthogonal to each other, and the optical systems for the left eye and the right eye An image display device for forming one screen for the left eye and one screen for the right eye, respectively. 3. A liquid crystal device having a ferroelectric liquid crystal or liquid crystal molecule between a first substrate having a plurality of electrodes connected to leads and a second substrate having electrodes connected to the leads. And, while projecting display light from the light source that has passed through the liquid crystal device onto a screen that is reflected or refracted by one surface, the one surface is synchronized with a display movement that is a linear light beam of the liquid crystal device. By rotating in one direction, the position of the display light projected on the screen is moved to form one screen, and when the one screen has been formed, it appears by rotating in one direction. The image display device, characterized in that another surface adjacent to the one surface has a rotating polyhedron for reflecting or refracting the display light for forming the next one screen, wherein the first substrate is Yes That in a plurality one of the electrodes has a selected time, the driving method of the image display device characterized by having thereby apply an electric field of only one pulse.