JPS60179823A - Light pen - 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 [Field of Application of the Invention] The present invention relates to a light pen, and more particularly to a light pen suitable for handwriting input on a liquid crystal display (flannel) having a handwriting input function using laser light.

[Background of the invention]

A benign method that allows direct handwriting input on the display panel, using a light pen equipped with a semiconductor laser to thermally write on a display/channel using a liquid crystal material whose main component is a liquid crystal with a smectic phase as the display material. Papers such as “:t,ight Pen andRead□ul
FunCtion5 in 'pharmaly A
ddre -5sed '8meCtiCLiQuid
Crystal Disl)laY”.

pr□cecding Of the 3rd: [n
internationalDisplayContere
Illce, pp. 490-493 (1983) is known.

The writing method according to this paper will be explained using FIG. 1.

The display panel consists of two glass substrates 1.・About 10μ between 2
It has a structure in which liquid crystal 3 having a smectic phase is sealed in a thickness of m. In the initial state, liquid crystal molecules are aligned perpendicularly to the substrate and have high light transmittance. Signal electrodes 4 made of a transparent electrode material are formed on the upper glass substrate 1, and heat electrodes 5 made of a metal material (such as Cr) are formed in stripes on the lower glass substrate 2, and are arranged in an XY matrix. .

The light pen 6 includes a semiconductor laser 7 having an oscillation wavelength in the near-infrared region, and lenses 8 and 9.

A laser beam emitted from a semiconductor laser 7 in a light pen 6 is focused onto a heat electrode 5 by lenses 8 and 9.

The heat electrode 5 absorbs the laser beam and generates heat locally, raising the temperature of the liquid crystal material near the heat electrode 5 to an isotropic phase (isotropic liquid phase). Next, light pen 6
When the liquid crystal material moves, the liquid crystal material, which once became an isotropic phase, is rapidly cooled and becomes a smectic phase again. At this time, a structure with strong scattering properties is exhibited, and writing is achieved.

In this way, according to the movement of the light pen, the character 1
Figures etc. can be drawn on the display panel.

This display device further detects the capacitance of each pixel and
It also has the ability to electrically read written information.
Applications in various fields are expected.

However, the light emitted from the near-infrared semiconductor laser used in the light pen shown in this paper cannot be recognized by the human eye. The drawback was that it was difficult to determine.

That is, as shown in FIG. 2, when a person inputs information using the light pen 6, it is natural to use the light pen 6 by tilting it at an arbitrary angle with respect to the surface of the liquid crystal display panel. At this time, the heat electrode 5 that absorbs the laser beam and generates heat in the liquid crystal display panel is placed deeper than the surface of the upper glass substrate 1 by approximately the thickness of the glass substrate.

Note that the thickness of the upper glass substrate is usually 1 to 3 Wms, the thickness of the signal electrode 4 is 1000 Å or less, and the thickness of the liquid crystal layer is 10 μm.
It is about m.

Therefore, heat is generated from the surface of the liquid crystal display panel where the light pen is placed under 1 to 3 TrrIn and writing is performed, resulting in a difference between position A where the light pen is placed and position B where writing is actually performed.

At this time, as mentioned above, since the laser beam is invisible to the human eye, it is difficult to accurately determine the plunge position.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light pen which eliminates the above-mentioned drawbacks and can clearly indicate the writing position.

[Summary of the invention]

The light pen of the present invention that achieves the above object is characterized in that it includes a first light source that emits invisible light and a second light source that emits visible light.

In a preferred embodiment of the present invention, the invisible light and the visible light are focused at substantially the same position.

Furthermore, in a preferred embodiment of the present invention, the visible light is emitted at least before the non-visible light is emitted.

Further, in a preferred embodiment of the present invention, contact of the light pen with an external object is detected to control at least the emission of the invisible light.

Furthermore, in a preferred embodiment of the present invention, the emission of the visible light is controlled by detecting that the light pen contacts an external object.

Further, in a preferred embodiment of the present invention, the first light source is a semiconductor laser, and the second light source is an LED.

[Embodiments of the invention]

A first embodiment of the light pen according to the present invention is shown in FIG.
explain.

Inside the light pen housing 20, a near-infrared semiconductor probe 21,
L E D (Light Emitt) that emits green light.
ingDiode) 220 Two light sources are provided. In addition, a wavelength-selective reflector 23 (commercially available as a dichroic mirror) that transmits the laser beam in the infrared region and reflects wavelengths near green in the visible region is arranged at an angle of approximately 45° with respect to the optical axis of the laser beam. It is arranged so that it forms. Lenses 24 and 25 are provided to focus the light emitted from the two light sources onto the heat polarization within the liquid crystal display panel.

In the light pen with the above structure, the semiconductor laser 21 is used as a heat source for inputting information such as characters and figures to the liquid crystal display panel, and the laser beam emitted from it is
The light passes through the wavelength selective reflector 23 and is focused at a predetermined position by the action of lenses 24 and 25. In experiments conducted by the present inventors, it was possible to input information onto the liquid crystal display panel at the speed at which characters are drawn using normal empi, using a laser oscillation output of 20 mW.

The green light emitted from the LED 2-2 is reflected by the wavelength-selective reflector 23, and is focused by the action of the lenses 24 and 25 at approximately the same point as the focal point of the laser beam. The LED used by the present inventors in the experiment was a commercially available one with a current of approximately 10 mA.
Sufficient light emission was obtained by passing a current of ~20 mA.

When inputting information on the LCD panel using a light pen like this,
Since the position where the laser beam is focused is indicated by glowing green light from the LED, the writing position can be clearly recognized, making it very easy to determine the input position.

A second embodiment of the present invention will be explained with reference to FIG.

A roughly cylindrical pen nib member 3 at the tip of the light pen housing 30
1 is attached so that it can move within the range of expansion and contraction of the spring 32. Also, a switch 3 is located inside the light pen housing 30.
3.34 is provided.

Furthermore, semiconductor lasers for information input, LE for visible light emission
The optical system such as D is the same as in the previous embodiment.

The switch 33 is used to control the light emission of the LED, and the switch 34 is used to control the light emission of the semiconductor laser. When the light pen is pressed onto the liquid crystal display panel, the pen tip member 31 is pushed and moves into the light pen housing while stretching the spring 32.

At this time, if the switch 33 is pushed in a certain distance,
operates and the LED lights up. Therefore, the writing position within the liquid crystal display panel appears bright.

In this state, when the light pen is moved and a predetermined position desired for writing is determined, and the light pen is further pressed down, the pen tip member 31 further moves into the light pen housing, and the switch 34 is operated. At this time, the semiconductor laser emits light for the first time, so writing is performed in advance at the position illuminated by the LED. Note that when the light pen is removed from the liquid crystal display panel, the pen tip member 31 is pushed out by the spring 32, so that all light emission stops.

As described above, according to the second embodiment, the actual writing can be performed after recognizing the writing position with the human eye in advance, so that input operations using a light pen can be performed very easily. Note that in this embodiment, visible light may always be emitted.

〔Effect of the invention〕

As explained above, according to the present invention, visible light can be used to
Since the focal position of the laser beam, which has a wavelength in the near-infrared region that humans cannot see, can be recognized, information can be input easily using a light pen.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a liquid crystal display device that allows handwritten input with a light pen, Fig. 2 is an explanatory diagram illustrating a writing operation with a light pen, and Fig. 3 is a route map showing the first embodiment of the present invention. , FIG. 4 is a route map showing the second embodiment. 20.30... Light pen housing, 21... Semiconductor laser, 22... LED, 23... Wavelength selective reflector, 24.25... Lens, 31... Pen tip member, 3
2...Spring, 33.34...Switch. Agent Patent Attorney Akio Takahashi No. 1 Prisoner's Law 2 Figure 6 1:5. q 13 Continuation of figure 1 page [Co., Ltd.] Inventor Masaaki Kitajima Hitachi City Saiwaimachi 3-chome premises

Claims (1)

[Scope of Claims] 1. A light pen characterized by comprising a first light source that emits invisible light and a second light source that emits visible light. 2. The light pen according to claim 1, wherein the invisible light and the visible light are focused at substantially the same position. 3. A light pen according to claim 1 or 2, characterized in that the light pen emits the visible light at least before emitting the invisible light. 4. Claims 1, 2, or 3 are characterized in that the light pen detects contact with an external object and controls at least the emission of the invisible light. A light pen. 5. The light pen according to claim 4, wherein the light pen detects that the light pen comes into contact with an external object to control the emission of the visible light. 6. The light pen according to claim 1, wherein the first light source is a semiconductor laser. 7. The light pen according to claim 1, wherein the second light source is an LED.