JPH063640A - Liquid crystal display device - Google Patents

Abstract

(57) [Summary] [Object] With regard to a liquid crystal display device, an object thereof is to be able to operate a cursor on a phase transition type liquid crystal display device which is an original screen for enlarged projection. [Structure] A screen display unit 1 including a screen display panel 1a and a screen drive unit 1b for displaying a phase transition type liquid crystal screen 5, and a cursor 6 including a cursor display panel 2a and a cursor drive unit 2b.
The cursor display unit 2 for displaying, the screen display panel 1a via the screen drive unit 1b, and the cursor display panel 2a via the cursor drive unit 2b are simultaneously controlled to display the cursor 6
Is displayed on the screen 5 at a predetermined position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device,
An object of the present invention is to provide a liquid crystal display device in which a cursor displayed in a cursor display section is optically combined with a screen displayed in a phase transition type screen display section and the cursor can be operated in a large capacity display screen.

Recently, with the development of large-capacity storage means such as an optical disk, it has become possible to easily store a huge amount of information such as video as well as character information. If such information is to be displayed on a desk, it can be easily performed by a CRT display device, which contributes to the progress of OA and CAD. However, when trying to display on a large screen, the device becomes exaggerated, and there is no display device called a simple projection type or projection type yet.

[0003]

2. Description of the Related Art Projection-type display devices are developed with a light source having a strong directivity such as a laser beam and development of semiconductor technology, and L
A display device having a high resolution and a flat display surface, such as a CD (liquid crystal display device), has come to be obtained, and has been regained attention.

Conventionally, a display device for enlarging and projecting a screen of a CRT on a screen has been known, and a system for enlarging and projecting a moving image of a commercial TV (television) on the screen has become widespread as a phosphor having high brightness is developed. I'm doing it.

On the other hand, the LCD uses an STN (super twisted nematic) liquid crystal and realizes a so-called active matrix driving in which TFTs (thin film transistors) are arranged in each pixel, and the manufacturing technology of the color filter is advanced, for example, for portable use. Color TVs for wall hangings are starting to appear.

However, in order to display a large amount of information, hundreds of thousands to millions of pixels are required, and the conventional TV is used.
It is difficult to obtain a bright and clear screen by enlarging and projecting an LCD due to restrictions such as the number of scanning lines and the scanning method. Therefore, as a solution to such a problem, a phase transition type liquid crystal display device having a memory function is drawing attention.

FIG. 3 is an explanatory view of a display principle of a phase transition type liquid crystal, and FIG. 3A is a display principle diagram of a phase transition type liquid crystal display device.
FIG. 3B shows the display principle of the STN type display device of the reference example. First, in FIG. 3 (B), a panel for an STN type display device is obtained, for example, when a transparent electrode is stacked on a glass substrate provided with a striped transparent electrode made of an ITO film so as to cross the transparent electrodes. The alignment film is formed so that the nematic liquid crystal is twisted, for example, by 270 °. Then, the two substrates are sealed to fill the liquid crystal. Then, polarizing plates are attached to both sides of the substrate. This structure is called a matrix structure.

Further, TFTs (thin film transistors) are arranged in parallel for each pixel on one substrate, and the other two substrates are covered with a common whole surface electrode to seal the liquid crystal.
This configuration is called an active matrix configuration.

In the case of this STN type display device, when no voltage is applied, the linearly polarized light which has passed through one of the polarizing plates passes through the other polarizing plate while rotating while rotating in the liquid crystal. Therefore, the state where no voltage is applied is the bright state.

On the other hand, when a predetermined voltage is applied, the alignment of the liquid crystal is disturbed, and the polarized light passing through one polarizing plate cannot pass through the other polarizing plate even though it passes through the liquid crystal. That is, the state in which the voltage is applied is the dark state. Then, when application of a voltage lower than the threshold voltage: V _{0 and} a voltage higher than the threshold voltage V ₀ is intermittently performed, bright / dark inversion rapidly occurs. And this inversion operation has a quick response.

Therefore, if the STN liquid crystal display device is a light valve type display device provided with illumination (backlight) on the back surface, it is possible to display TV moving images in color by combining with a color filter.

On the other hand, in FIG. 3A, the panel of the phase transition type liquid crystal display device has a structure in which a phase transition type liquid crystal is sealed between two substrates provided with transparent electrodes. Now
Assuming that the reference voltage is V ₀ , when the transmission mode (bright state) is changed to the scattering mode (dark state), first, the application electrode:
After the voltage is set to 0 V and the light is scattered, the reference voltage is set to V ₀ .
Then, the scattering mode is maintained and the dark state is stored.

Next, when changing from the scattering mode to the transmission mode, first, the applied voltage: 2V ₀ is applied to set the transmission mode, and then the reference voltage: V ₀ . Then, the transparent state is held and the dark state is stored.

By the way, in the phase transition type liquid crystal, the transmission mode is a nematic phase and the scattering mode is a cholesteric phase. This phase transition takes, for example, a transmission → scattering (cholesteric phase → nematic phase) transition of several ms and a scattering → transmission (nematic phase → cholesteric phase) transition of several tens ms per line.

As described above, the relationship between the applied voltage and the light transmittance has a history. Therefore, if the driving voltage is set to V ₀ after each mode transition of transmission / scattering, the two modes can be stably maintained.

Using the display principle of this phase transition type liquid crystal,
Large display capacity several times that of conventional LCDs, eg 2,000
It can display a large capacity of several million pixels such as × 2,000 pixels. It takes several seconds to several tens of seconds to rewrite the screen, but once the display screen is held, the fixed screen becomes the original screen (original image) and it is easy to enlarge and project using the optical system. Is possible.

[0017]

By the way, FIG. 3 (B)
In the STN type display device shown in (1), each pixel is always electrically scanned to drive the liquid crystal for display. Therefore, the operation of moving the cursor to specify the display position or partially rewriting it can be easily performed. However, when the number of pixels is gradually increased in order to display a large capacity, for example, in the case of a simple matrix structure, there is a problem in the response of the liquid crystal, and in the case of an active matrix structure, there is a problem in the TFT manufacturing process. It becomes difficult to realize for some reason.

On the other hand, in the case of the phase transition type liquid crystal display device shown in FIG. 3 (A), the display is memorized if it is once scanned with a matrix structure. Therefore, it is possible to easily display a large-capacity screen having hundreds of thousands to millions of pixels.

However, since the phase transition type liquid crystal display device has a memory function, it is not possible to move the cursor to specify the display position and partially rewrite it. Therefore, for example, a screen that has been
It is necessary to perform a troublesome work of rewriting the entire screen of the liquid crystal screen after displaying the contents on T or the like to confirm the contents.

Therefore, according to the present invention, the cursor displayed on the cursor display section is optically combined with the screen displayed on the phase transition type screen display section so that the cursor can be operated on the enlarged and projected screen. The purpose is to provide a device.

[0021]

[Means for Solving the Problems] The above-mentioned problem has a screen display section, a cursor display section, a control section, and a projection means, and the screen display section displays a phase transition type liquid crystal screen. Which has a screen display panel and a screen drive section, wherein the cursor display section displays a cursor, and has a cursor display panel and a cursor drive section, The control unit is configured to simultaneously control the screen display panel via the screen drive unit and the cursor display panel via the cursor drive unit to display the cursor at a predetermined position on the screen. It is solved by a liquid crystal display device.

[0022]

In the phase transition type liquid crystal display device having the memory function, the cursor cannot be displayed. However, in the present invention, the cursor can be operated so that the cursor can be moved within the screen. ing.

That is, in addition to the screen display unit composed of the phase transition type liquid crystal display device, a cursor display unit dedicated for cursor display is separately provided, and the screen drive unit of the screen display panel and the cursor drive unit of the cursor display panel are common. It is controlled by the control unit. Then, the screen of the screen display unit and the cursor of the cursor display unit are optically combined.

Then, when the cursor is moved,
It can also be operated as if the cursor is moving on the screen. Therefore, it is possible to easily specify the position of the screen or partially rewrite it with the cursor.

[0025]

FIG. 1 is a schematic perspective view of an embodiment of the present invention,
FIG. 2 is a schematic perspective view of another embodiment of the present invention. In the figure, 1 is a screen display unit, 1a is a screen display panel, 1b is a screen drive unit, 2 is a cursor display unit, 2a is a cursor display panel, 2b is a cursor drive unit, 3 is a control unit, 4 is projection means, and 4a. Is a light source, 4b is an optical system, 4c is a screen, 5 is a screen, 6 is a cursor, and 10 is a liquid crystal display device.

1 and 2, a liquid crystal display device 10 according to the present invention is composed of four members, a screen display section 1, a cursor display section 2, a control section 3 and a projection means 4. First,
The screen display unit 1 is a phase transition type liquid crystal display device having a memory function, and a screen display panel 1a for exclusively displaying a screen 5
And a screen drive section 1b for driving the screen display panel 1a.

On the other hand, the cursor display portion 2 is, for example, STN
A liquid crystal simple matrix liquid crystal display device or an active matrix liquid crystal display device driven by TFTs may be used. Further, for example, a liquid crystal display device using FLC (ferroelectric liquid crystal) may be used. Then, a cursor display panel 2a for exclusively displaying the cursor 6 and the cursor display panel 2a
And a cursor drive unit 2b for driving the.

The control unit 3 is connected to the screen drive unit 1b and the cursor drive unit 2b to control the two drive units 1b and 2b at the same time.
The screen 5 displayed by the screen display panel 1a and the cursor 6 displayed by the cursor display panel 2a are displayed in synchronization with each other.

The projection means 4 includes a light source 4a for illuminating the screen display panel 1a and the cursor display panel 2a from the back, an optical system 4b for optically combining the screen 5 and the cursor 6 of those panels 1a and 2a, and And a screen 4c on which the cursor 6 is enlarged and projected.

Embodiment 1 In FIG. 1, a cursor display panel 2a is superposed on a screen display panel 1a. Then, the cursor 6 of the cursor display panel 2a is moved corresponding to the screen 5 of the screen display panel 1a, the position of the screen 5 can be designated, and the projection means 4 enlarges and projects it on the screen 4c in a superimposed state. Has become.

According to the liquid crystal display device 10 constructed as described above, the phase transition type liquid crystal display device which cannot be operated by the cursor 6 in the past is moved within the screen 5 on the screen 4c. The cursor 6 can be moved like this. Then, the cursor 6 can be used to specify the position and rewrite.

Embodiment 2 In the liquid crystal display device 10 shown in FIG. 2, the screen display panel 1a and the cursor display panel 2a are arranged side by side.
The screen drive unit 1b and the cursor drive unit 2b are simultaneously controlled by the control unit 3 so that the screen 5 of the screen display panel 1a and the cursor 6 of the cursor display panel 2a are relatively aligned. .

The projection means 4 is provided with two sets of light sources 4a and an optical system 4b, and the screen 5 and the cursor 6 of the respective panels 1a and 2a are united to project them on the screen 4c in an enlarged scale.
Then, on the screen 4c, the position can be specified so that the cursor 6 can be moved in the screen 5 or partial rewriting can be performed.

Although the projection means 4 is illustrated as having an integral structure in this example, the screen display unit 1 and the cursor display unit 2 (and the control unit 3) are integrally configured, for example, an existing OHP (overhead projector). It can also be placed on the screen for projection display. Further, the projection means 4 can be variously modified in the number and arrangement of the light sources 4a and the optical system 4b depending on the size and magnification of the panels 1a and 2a and the screen 4c.

[0035]

Since the phase transition type liquid crystal display device having a memory function can display a large capacity of several million pixels, it is useful as an original screen for enlarged projection, but it has a drawback that cursor display is not possible. On the other hand, according to the present invention, a cursor display unit is separately provided and optically combined with the screen display unit, so that the cursor can be operated so that it can be moved within the screen.

As a result, the present invention greatly contributes to the spread and development of the phase transition type liquid crystal display device which is expected to be used for enlarging and projecting a large-capacity display screen, such as realization of an electronic OHP.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an embodiment of the present invention.

FIG. 2 is a schematic perspective view of another embodiment of the present invention.

FIG. 3 is an explanatory diagram of a display principle of a phase transition type liquid crystal,
(A) is a display principle diagram of a phase transition type liquid crystal display device, and (B) is a display principle of an STN type display device of a reference example.

[Explanation of symbols]

1 screen display section 1a Screen display panel 1b
Screen drive 2 Cursor display 2a Cursor display panel 2b
Cursor drive unit 3 Control unit 4 Projection means 4a Light source 4b
Optical system 4c Screen 5 Screen 6 Cursor 10 Liquid crystal display

Claims (4)

[Claims] 1. A screen display unit (1) and a cursor display unit (2)
And a control unit (3), wherein the screen display unit (1) displays a screen (5) of a phase transition type liquid crystal, and includes a screen display panel (1a) and a screen drive unit.
(1b), the cursor display unit (2) is for displaying a cursor (6), and has a cursor display panel (2a) and a cursor drive unit (2b), The control unit (3) simultaneously controls the screen display panel (1a) via the screen drive unit (1b) and the cursor display panel (2a) via the cursor drive unit (2b) to control the cursor
A liquid crystal display device characterized in that (6) is displayed at a predetermined position on the screen (5). 2. The liquid crystal display device according to claim 1, wherein the cursor display panel (2a) is disposed above or below the screen display panel (1a) so as to be overlapped with each other. 3. A projection means (4), said projection means (4) having a light source (4a), an optical system (4b) and a screen (4c), and said light source (4a). ) Illuminates the panels (1a) and (2a) from the back side, and the optical system (4b) merges the cursor (6) with the screen (5) and the screen (4
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is enlarged and projected on c). 4. The liquid crystal display device according to claim 3, wherein the cursor display panel (2a) is arranged side by side on the screen display panel (1a).