JPH0429087B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a projector for enlarging and projecting data such as desired characters and figures on a screen. The present invention relates to a projection type liquid crystal display device that inputs arbitrary data by specifying the position of the screen, displays the data on a liquid crystal display, and projects this display onto a screen.

[Conventional technology]

When giving lectures or research presentations in large venues, explanations may be given while enlarging and projecting data and figures using a projector. Conventional projectors of this type have a transparent film with characters and figures written on it placed on a magnifying reflector, and the data and figures are enlarged and projected onto the screen on this film. Therefore, the speaker must write the necessary data on the film in advance.
Not only is the work time-consuming, but it also has drawbacks such as not being able to easily modify the manuscript.

The applicant previously filed Japanese Patent Application No. 59-41376
In 186924), a coordinate input device with a display was proposed in which a liquid crystal panel was mounted on a tablet and displayed positional coordinates designated by a magnetic pen or the like or image information based on the coordinates. This device has the advantage that arbitrary data can be entered with high precision simply by operating an input pen on the display, and the input results can be immediately confirmed on the display.

[Purpose of the invention]

The purpose of the present invention is to provide a projection type liquid crystal display, which outputs and displays characters, figures, etc. that are handwritten into a tablet on a liquid crystal display panel, and projects the output and displayed images, focusing on the advantages of the prior invention described above. An object of the present invention is to provide a display device.

[Structure of the invention]

The projection type liquid crystal display device of the present invention includes a tablet capable of inputting information such as handwritten characters and figures, a liquid crystal display panel superimposed on the tablet, and a reflective screen provided between the tablet and the liquid crystal display panel. a control means for outputting and displaying information input into the tablet on a liquid crystal display panel; a light source means for irradiating light onto the liquid crystal display panel; and a light source means for projecting reflected light from the liquid crystal display panel onto a screen. It is characterized by having a projection lens.

[Effect]

In this way, with this projection type liquid crystal display device, handwritten information input into the tablet through the liquid crystal display panel, information input directly into the tablet from an external device, etc. are displayed in a visible state on the liquid crystal display panel. The light emitted from the light source means above is reflected by a reflecting member, and the reflected light is projected onto a screen or the like by a projection lens. Since the light from the light source means only passes through the liquid crystal display panel, the attenuation of the amount of light can be suppressed slightly.
The light from the light source can be used effectively.

〔Example〕

Hereinafter, an embodiment of the present invention shown in the drawings will be described. At the upper end of a support arm 3 whose lower end is attached to a base case 1 via a support shaft 2 etc., a light source 4, two reflecting mirrors 5, 6, and convex lens 7
A projector case 8 that accommodates the is attached. The light from the light source 4 is configured to illuminate the upper surface of the base case 1 through a lower opening 9 by a reflecting mirror 5. Although not shown, a condenser lens is provided between the light source 4 and the reflecting mirror 5.

On the upper surface of the base case 1, which is exposed to light from the light source 4, there is provided a well-known transmissive liquid crystal display 11 in which a liquid crystal medium is interposed between a plurality of crossed horizontal electrodes and vertical electrodes. As shown in detail in FIG. 2, on the bottom surface of this liquid crystal display 11, figures and characters are drawn using a flat concave mirror 12, which is a reflective member, and an input pen 13, which generates a steady magnetic field. Break it down into X-axis and Y-axis coordinates,
A tablet 14 for detecting coordinate positions is arranged. The structures of the input pen 13 and tablet 14 are explained in detail in, for example, the above-mentioned Japanese Patent Application No. 59-41376, so a detailed explanation thereof will be omitted.

As shown in FIG. 2, the concave mirror 12 has a large number of concentric grooves 16 formed at a fine pitch on the upper surface of a thin aluminum substrate 15 with a thickness of approximately 1 mm, and the surface of each groove 16 is inclined toward the center. It is composed of a Fresnel lens with a curved surface. A transparent synthetic resin coating layer 17 is provided to cover these grooves 16, so that the upper surface of the concave mirror 12 is flat. Therefore, the refraction caused by the concave mirror 12 is very small, and the magnetism from the input pen 13 placed on the liquid crystal display 11 can detect the coordinate position of the tablet 14 located almost directly below.
By this concave mirror 12, the light from the light source 4 is reflected by the reflecting mirror 5 and the concave mirror 12, then converged by the convex lens 7, and projected onto the screen 10 by the reflecting mirror 6 supported so that its angle can be adjusted. .

Inside the base case 1, there is a control circuit 1 for processing coordinate data detected by the tablet 14.
8 is stored. Also, externally, data from the control circuit 18 is sent to the liquid crystal display 11 to display the data on this display, and the data is sent to a monitor TV or printer (not shown) for display or storage. A processing device 19 is provided for processing. Of course, this processing device 19 may also be housed within the base case 1.

Next, the tablet 14 and the liquid crystal display 11
The operation control will be explained with reference to FIG. The tablet control circuit 21 includes a tablet 14, an X-direction multiplexer 22, and a Y-direction multiplexer 2.
3, the voltage induced by electromagnetic induction is detected by the detection line in the tablet 14, and the locus of the figure or character is used as the X and Y coordinates, and the voltage is transmitted through the The induced voltage of the lever is sent to the control circuit 18.

In the control circuit 18 , the induced voltage is amplified by an amplifier 31 , rectified into a DC voltage by a detector 32 , and further converted into a digital value by an analog-to-digital (A/D) converter 33 . This digital signal is applied to an arithmetic processing circuit 35 via an input buffer 34. In the arithmetic processing circuit 35, the previous sample induced power (digital value) temporarily stored in the memory 36
and the data taken in from the input buffer 34 to determine the X-coordinate value or Y-coordinate value. This arithmetic processing circuit 35 also sends control signals to the X-direction and Y-direction multiplexers 22 and 23 via an output buffer 37, and
The induced voltage in the direction is alternately sent to the amplifier 31. The drive power supply 38 supplies a sinusoidal current to the excitation line of the tablet 14.

The timing signal supplied to the input buffer 34 sends data from the tablet 14 from the arithmetic processing circuit 35 to the processing unit 19 only while the input pen 13 is drawing figures or characters on the tablet 14.

The position data consisting of coordinate values in the X and Y directions sent to the processing device 19 is sent to the display drive circuit 4.
It is also sent to the display memory 42 via the display control circuit 41 of No. 0, and is arranged and stored in a certain order.
The signals are sequentially read out and output to the X-direction driver 43 and the Y-direction driver 44 according to timing pulses from . A scanning pulse generated by a scanning circuit 45 in synchronization with the timing pulse is input to the X direction driver 43 and the Y direction driver 44, and each driver 43, 44 corresponds to the coordinates of the liquid crystal display 11 in the X direction and Y direction. The position indicated on the tablet 14 is displayed at the same position on the liquid crystal display 11.

In this way, the loci of figures and characters drawn by the input pen 13 on the liquid crystal display 11 are displayed on the liquid crystal display 11 in a visually visible manner in the same locus. The display on the liquid crystal display 11 is projected onto the screen 10 by light from the light source 4.

By adding a character editing function to the processing device 19, input characters, etc. can be modified, added, or deleted. Furthermore, if a graphic processing function is added, it is possible to use CAD, CAN, etc., so it is possible to display not only handwritten characters and figures, but also sentences and figures prepared in advance. Furthermore,
The position data sent to the processing device 19 can be recorded on a floppy disk or a hard copy can be obtained via a printer.

〔Effect of the invention〕

As described above, the projection type liquid crystal display device of the present invention allows desired figures and characters to be displayed on the liquid crystal display by moving the input pen so as to specify the coordinate position on the tablet via the liquid crystal display and the reflective member. At the same time, the characters and figures displayed on this liquid crystal display can be projected and displayed on the screen, so there is no need to prepare a document to be projected in advance as with conventional projectors, and you can fill in it on the spot. Furthermore, corrections can be made very easily. Since the light from the light source means only passes through the liquid crystal display panel, the amount of light can be attenuated only slightly, and the light from the light source can be used effectively.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view schematically showing an embodiment of the present invention, and FIG. 2 shows details of a concave mirror.
FIG. 3 is a block diagram showing a drive circuit for a tablet and a liquid crystal display. In the drawing, 4 is a light source, 7 is a projection lens, 1
1 is a liquid crystal display, 12 is a concave mirror, 13 is an input pen, 14 is a tablet, 18 is a control circuit, 1
9 is a processing device.

Claims (1)

[Scope of Claims] 1. A tablet capable of inputting information such as handwritten characters and figures, a liquid crystal display panel superimposed on the tablet, and a reflective member provided between the tablet and the liquid crystal display panel. and a control means for controlling the information input to the tablet to be output and displayed on the liquid crystal display panel;
A projection type liquid crystal display device comprising: a light source means for irradiating light onto the liquid crystal display panel; and a projection lens for projecting reflected light from the liquid crystal display panel onto a screen. 2. The projection type liquid crystal display device according to claim 1, wherein the reflective member is composed of a flannel lens.