JPH04149417A - Liquid crystal display device for projection - Google Patents

Abstract

PURPOSE:To increase the degree of freedom of an installation place and to easily recognize a projection image by providing an image inversion switching means which switches an image to be displayed on a liquid crystal display plate between a normal image and an inverted image. CONSTITUTION:This display device is equipped with an input part 2 for inputting image information, a control part 4 which processes the input image information, the liquid crystal display plate 6 which displays the image information from the control part 4, and the image inversion switching part 8 which switches the image to be displayed on the liquid crystal display plate 6 between the normal image and inverted image. In this case, when the image inversion switching means 8 displays the normal image, an OHP 20, etc., is arranged in front of a screen 140 and the image is projected in normal use mode; when the image is switched to the inverted image, the inverted image is projected on the screen 140 from behind and a person in front of the screen 140 can confirm the normal uninverted image. Consequently, the image which can easily be viewed by the viewer can be projected according to the place of use.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a projection liquid crystal display used in an electronic blackboard system, etc., in which liquid crystal display contents are projected onto a screen by an overhead projector (hereinafter also referred to as OHP). It is related to the device.

[Conventional technology]

OHP is widely used in meetings with a large number of people to provide easy-to-understand explanations using diagrams, etc.
OHP is used by projecting what is written on a transparent sheet onto a screen as a manuscript, but in addition to this, there is also a liquid crystal display in which a liquid crystal display device is installed on the OHP and the contents displayed on this are projected onto the screen by OHP. Display devices are known. In other words, a transmissive liquid crystal display device is placed on an OHP document stage, and light from a light source located at the bottom of the document stage is passed through the liquid crystal display device, and the focus is adjusted using an optical system such as a mirror. etc., to project the content displayed on the liquid crystal display device onto the screen.

By using the content displayed on this liquid crystal display device as an OHP document, CR of a personal computer can be improved.
The same image as the T screen can be enlarged and projected, allowing a large number of people to view the same image at the same time.

[Problem to be solved by the invention]

Incidentally, an OHP is usually installed in front of the screen on the viewer's side to perform projection. For this reason, in OHPs using conventional projection liquid crystal display devices, there is a problem in that the projection liquid crystal display device, OHP, etc. become an obstacle for those behind the OHP when viewing the screen, making it difficult to see the projected image. was there.

Furthermore, when there are a large number of caregivers, it may be difficult to find a place to install an OHP that requires a control unit, power cord, etc.

The present invention has been made based on the above-mentioned circumstances, and it is an object of the present invention to provide a projection liquid crystal display device that has a greater degree of freedom in installation location and can easily recognize projected images.

[Means to solve the problem]

To achieve the above object, the present invention provides a projection liquid crystal display device for displaying an image to be projected on a screen on a liquid crystal display panel, which includes an image reversal switching means for switching the image between a normal image and an inverted image. , is characterized in that the image can be projected not only from the front of the screen but also from the rear.

[Function] The present invention has the above-mentioned configuration, and by providing an image reversal switching means, when an image is displayed as a normal image, OHP
etc. in front of the screen for normal use! An image can be projected in a manner.

Further, when the image is switched to an inverted image by the image inversion switching means, by projecting the inverted image from behind the screen, a person in front of the screen can recognize the normal non-inverted image.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a schematic block diagram of a projection liquid crystal display device according to an embodiment of the present invention. In FIG. 1, 2 is an input unit for inputting image information, 4 is a control unit for processing the input image information, 6 is a liquid crystal display board for displaying image information from the control unit, and 8 is a display unit for displaying image information on the liquid crystal display board. The projection liquid crystal display device 16 of this embodiment is an image reversal switching unit that switches an image between a normal image and an inverted image. Be equipped.

In the present invention, as shown in FIG. 1, image information input from an input section 2 is sent to a control section 4, subjected to image processing, and then supplied to a liquid crystal display board 6. At this time, the image displayed on the liquid crystal display panel 6 is switched to a normal image or a reversed image by the image reversal switching unit 8 depending on the usage mode of the OHP.

Next, a case will be described in which a normal image is displayed on a liquid crystal display panel in a projection liquid crystal display device which is an embodiment of the present invention. FIG. 2 is an overall configuration diagram of an electronic blackboard system constructed using the projection liquid crystal display device of this embodiment.

The electronic whiteboard system shown in FIG. 2 includes a personal computer 12 as a control unit, an electronic whiteboard 14 that also serves as a screen, a projection liquid crystal display device 16 having a liquid crystal display board 6, and a projection liquid crystal display device. 16 for projecting the image displayed on the electronic blackboard 14, a printer 22 for printing the image displayed on the projection liquid crystal display device 16, and a pen with a built-in magnetic material (not shown) that is an input section for image information. It is equipped with a keyboard 24 and the like.

The projection liquid crystal display device 16 is installed at a predetermined position on the original stage of the 0HP20. This 0HP20 is of the type that has a light source below the document placement stage, but it may also be of the type that has the light source above the document placement stage.An electronic whiteboard 14 is installed in front of the 0HP20. . The position of this electronic blackboard 14 is 0HP2
It is determined relative to ○HP20 so that the projected image from 0 is projected at a predetermined position on the electronic whiteboard 4.

In this electronic blackboard system, a magnetic detection bag f1. (not shown) is provided. This device consists of a large number of amorphous alloys arranged in the X and Y directions, and when a pen with a built-in magnetic material approaches and touches the writing surface of the electronic blackboard 14, that position is excited by the magnetic material, and the amorphous alloy at that position is The magnetic permeability of the alloy changes. By sensing this change with a coordinate decoder (not shown), the coordinates of the pen on the writing surface of the electronic blackboard 14 are recognized.

The coordinate information obtained by the coordinate decoder is sent to the personal computer 12 shown in FIG. 2, processed for image display, and supplied to the liquid crystal display panel 6. The liquid crystal display board 6 displays information from the personal computer 12, just like the CRT screen of the personal computer 12. Therefore, anything that can be displayed on a CRT screen can be displayed on this liquid crystal display board 6, including colors.

Currently, the OHP 20 is placed in front of the electronic whiteboard I4 and is used in a normal manner for projection, so the image reversal switching section is configured to switch between the personal computer 12 and the personal computer 12 so that the image displayed on the liquid crystal display board 6 becomes the normal image. is giving instructions to.

This image is projected onto the electronic blackboard 14 by the 0HP20.

Incidentally, in addition to the magnetic material, the pen includes a microsinch and an LC resonant circuit. The microsinch is turned on by bringing the pen into contact with the writing surface of the electronic blackboard 14, and the LC resonant circuit starts oscillating. This resonance frequency is set to a different value depending on the color displayed, and this frequency is sensed by a coil embedded inside the electronic blackboard 14. Since the personal computer 12 is set in advance with information on the color to be displayed based on this resonance frequency, characters, etc. can be displayed in color on the liquid crystal display board, and the color display image can be projected onto the electronic blackboard by using an OHP. can do.

Erasers for erasing projected images are also equipped with such a device, and by identifying a predetermined resonance frequency, a! It is now possible to understand. When it is recognized that the frequency is the eraser frequency, the content displayed on the writing surface in the area through which the eraser passes is erased in real time.

In this way, an image by the liquid crystal display bag 216 is projected on the writing surface of the electronic whiteboard 14 in real time in accordance with the trajectory of the movement of the magnetic pen as described above. Therefore, it appears as if the image is being drawn directly on the writing surface with a pen.

Next, a case will be described in which an image is switched to an inverted image and displayed on a liquid crystal display board in an OHP liquid crystal display device. FIG. 3 is an overall configuration diagram of a liquid crystal image projecting device constructed using the same projection liquid crystal display device as shown in FIG.

The above-mentioned electronic blackboard system uses the normal method of use in which the OHP is placed in front of the screen and projected. In this case, the OHP is located at the guard of the observer, so the person behind For some users, the OHP etc. may get in the way and make it difficult to see the projected image.

Therefore, in such a case, we decided to make it possible to project images not only from the front of the screen but also from the back.
The projection liquid crystal display device of this embodiment is provided with an image reversal switching section 8 for reversing and returning the image display.

When displaying an image in reverse using the image reversal switching unit 8, the image is projected from behind the screen. For this reason, it is necessary to use, for example, frosted glass as a screen instead of an electronic whiteboard or a normal screen.

The liquid crystal image projection device shown in FIG. An 0HP 20 that projects onto a frosted glass 140, a printer 22 that prints the image displayed on the projection liquid crystal display device 16, a keyboard 24 and a tablet left 2 that are image information input means.
6. Here, except for the frosted glass 140, the same ones as those used in the electronic whiteboard system shown in FIG. 2 above are used.

The liquid crystal display device 16 is installed at a predetermined position on the original stage of the OHP 20. 0HP20 projects an image from behind the frosted glass 140.

The observer's seat is provided on the opposite side of the 0HP 20 through a frosted glass 140.

Contents input using the keyboard 24 or tablet 26 are sent to the personal computer 12, processed for image display, and supplied to the liquid crystal display board 6.

The personal computer 12 uses the image inversion switching section to invert this image information and display it on the liquid crystal display board 6. This image is projected onto the ground glass 140 from behind by the OHP 20. When this projected image is viewed from the side where 0HP20 is located, the force is reversed (when viewed from the viewer's side, it looks like a normal normal image).

This LCD image projection device projects images from behind the screen (frosted glass), making it possible to use a wide space in the viewer's seat and making it easier to recognize the image because there are no obstacles in front of the viewer's eyes. becomes easier.

In this way, the projection liquid crystal display device of this embodiment can switch the image between the normal image and the reversed image using the image reversal switching unit according to the usage mode of the OHP, and project the image not only from the front of the screen but also from the rear. can do. Therefore, the degree of freedom in the installation location is much greater than in the conventional case, and an image that is easily visible to the viewer can be projected.

In the above embodiment, a case has been described in which the image reversal switching unit is provided in a projection liquid crystal display device, but the present invention is not limited to this. It may also be configured using .

Furthermore, in the above embodiment, a case has been described in which an image obtained by processing input contents on a personal computer is projected on a screen in real time, but the present invention is not limited to this, and the present invention is not limited to this. The content may be saved in a file and played back at the time of presentation.

〔Effect of the invention〕

As explained above, according to the present invention, by providing the image reversal switching means, it is possible to project an image by placing the OHP not only in front of the screen but also behind the screen.
It is possible to provide a projection liquid crystal display device that can project an image that is easy for viewers to view depending on the place of use.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a projection liquid crystal display device that is an embodiment of the present invention, and FIG. 2 is an overall electronic whiteboard system configured using the projection liquid crystal display device that is an embodiment of the present invention. FIG. FIG. 3 is an overall configuration diagram of a liquid crystal image projecting device constructed using this liquid crystal display device for projection. 2... Input section, 4... Control section, 6... Liquid crystal display board, 8... Image reversal switching section, 12.
...Personal computer, 14...Electronic whiteboard, 16...Liquid crystal display device for projection,
20...Overhead projector, 22...Printer, 24...Keyboard, 26...Tablet, ]40. ...frosted glass. Applicant Nippon Steel Information and Communication Systems Co., Ltd. Applicant Techno Plane Co., Ltd. Agent Patent Attorney Han 1) Masao

Claims (1)

[Claims] In a projection liquid crystal display device that displays an image to be projected on a screen on a liquid crystal display board, an image reversal switching means is provided for switching the image between a normal image and an inverted image, and the screen can be viewed not only from the front of the screen but also from the rear. A projection liquid crystal display device, characterized in that it is configured to be able to project the image.