JPH05257109A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To maintain a liquid crystal panel always at an optimum temp. regardless of a change in outdoor air temp. by detecting the peripheral temp. of a liquid crystal element and controlling the heating temp. CONSTITUTION:A peripheral temp. detecting means, such as thermometer measuring resistor 32, which is attached on a metallic case 24, etc., of a liquid crystal block 22 and detects the peripheral temp., i.e., outdoor air temp. around the liquid crystal element 7 and a temp. control means which is a temp. control circuit 35 having a temp. correcting circuit 33 for controlling the heating temp. of a bar-shaped heater 30 according to a change in the peripheral temp. of the liquid crystal element 7 detected by this side thermometer measuring resistor 32 and an amplifier 34 are installed to the liquid crystal element 7. The temp. correcting circuit 33 of the temp. control circuit 35 is provided with a temp. coefft. which is negative with the peripheral temp. of the liquid crystal element 7. Then, the heating temp. of the bar-shaped heater 30 is lowered when the peripheral temp. rises. The metallic cases 24, 25 of the liquid crystal blocks 22, 23 are thus heated and held always at the specified temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light heat writing type liquid crystal display device for projecting and displaying an optical image such as a figure recorded on a liquid crystal element on a screen by irradiation of laser light. ..

[0002]

2. Description of the Related Art Conventionally, there has been used a liquid crystal element composed of a liquid crystal panel having a liquid crystal layer sandwiched between transparent substrates, and a liquid crystal panel holding means composed of a metal case and a glass plate for holding and keeping the temperature of the liquid crystal panel. , A phase change of the liquid crystal caused by heat generated by irradiating the liquid crystal element with laser light causes an optical image such as a figure to be recorded on the liquid crystal element, and the optical image is projected and displayed on a screen or the like by a projection display means. There is a liquid crystal display device of the thermal writing type using the laser light (see, for example, JP-A-58-42372).

In this type of heat writing type liquid crystal display device using laser light, the power of phase change of the liquid crystal is insufficient only by the heat generated by the irradiation of laser light.
Conventionally, the entire liquid crystal panel is covered with a metal case and a glass plate, the metal case is heated to a constant temperature by a heater, the liquid crystal panel is held by the glass plate, and the liquid crystal panel is kept at a constant temperature.

[0004]

However, in the past, the temperature of the liquid crystal panel was likely to change due to the change in the outside air temperature.

Conventionally, there has been no method other than increasing the thickness of the glass plate as a measure for reducing the influence of the temperature change of the liquid crystal panel due to the outside air temperature. However, increasing the thickness of the glass plate has adverse effects such as a decrease in the power of the laser light and a decrease in the light transmittance. Therefore, the thickness of the glass plate is limited.

Therefore, conventionally, when the outside air temperature decreases, the thickness of the drawing line of the liquid crystal panel by the laser light becomes too thin according to the standard, or it becomes impossible to draw in an extreme case. In addition, there is a problem that the drawing line becomes thicker than the standard when the outside air temperature rises.

The present invention has been made in order to solve the above problems, and provides a liquid crystal display device capable of always maintaining an optimum temperature of a liquid crystal panel regardless of a change in outside air temperature. The purpose is to

[0008]

According to a first aspect of the present invention, there is provided a liquid crystal display device, wherein an optical image is recorded by a phase change of the liquid crystal due to heat generated by irradiation with laser light. A liquid crystal display device comprising an element and means for projecting and displaying the optical image, wherein the liquid crystal element has a liquid crystal panel and means for holding the liquid crystal panel, and detects the ambient temperature of the liquid crystal element to detect the liquid crystal. By providing a temperature control means for keeping the temperature of the liquid crystal panel constant by controlling the heating temperature of the panel holding means. According to a second aspect of the present invention, the liquid crystal panel holding means includes a metal case and a glass plate that cover the entire liquid crystal panel, and the ambient temperature detecting means and the heating means of the temperature control means are attached to the metal case.

[0009]

According to the first aspect of the liquid crystal display device of the present invention constructed as described above, the ambient temperature control means detects the ambient temperature of the liquid crystal element to control the heating temperature of the liquid crystal panel holding means. Therefore, when the ambient temperature becomes high, the heating temperature is lowered, and when the ambient temperature becomes low, the heating temperature is raised so that the liquid crystal panel holding means can always be heated and held at a constant temperature. According to a second aspect of the present invention, the entire liquid crystal panel is covered with the metal case and the glass plate, and the ambient temperature detecting means and the heating means of the temperature control means are attached to the metal case.
The heat retention effect of the liquid crystal panel is high.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the liquid crystal display device of the present invention will be described below with reference to the drawings.

First, the optical block of the entire liquid crystal display device will be described with reference to FIG.

Laser light emitted from a laser light source such as a semiconductor laser 1 is reflected by a dichroic mirror 7 via a Y scanner 2, a relay lens 3, an X scanner 4 and an f-θ lens 5, and is applied to a liquid crystal element 7. To do.
At that time, the laser light is focused on the liquid crystal surface of the liquid crystal element 7 by the f-θ lens 5, and the Y scanner 2 and the X scanner 4 scan in the two-dimensional directions of the Y axis direction and the X axis direction. An optical image such as a figure is recorded (drawn) on the liquid crystal element 7 by the phase change of the liquid crystal due to the heat generated by the irradiation of the laser light. Then, the projection light emitted from the projection light source such as the metal halide lamp 8 is transmitted to the liquid crystal element 7 through the condenser lens 9 and the dichroic mirror 6, and the transmission light is projected by the projection lens 10 by the projection means. The optical image such as a figure recorded in the element 7 is enlarged and projected (displayed) on the screen 11 or the like.

Next, the details of the liquid crystal panel 13 of the liquid crystal element 7 and the principle of thermal writing of an optical image will be described with reference to FIG.

First, the liquid crystal panel 13 has a pair of transparent conductive films 15 on both sides of a liquid crystal layer 14 in which liquid crystal and a special dye are mixed.
And a transparent substrate such as a glass substrate 16 and the like.
A low voltage circuit 19 having a power source 17 and a switch 18 is connected to the pair of transparent conductive films 15.

Next, the write mode shown in FIGS. 2A and 2B is generated by the energy of the laser light when the liquid crystal layer 14 is instantaneously irradiated with the laser light with the switch 18 in the OFF state. The special dye is heated by the heat to form a scattering structure in the liquid crystal due to the phase change, and the pixel 20 which is the light blocking structure is formed by the rapid cooling effect after the passage of the laser light. Then, an optical image such as a figure is written (recorded) by a drawing line which is a continuous line of the pixels 20 and is projected and displayed on the screen 11 or the like.

2C, the switch 18 is turned on, and a low voltage is applied to the pair of transparent conductive films 15 by the low voltage circuit 18, so that the liquid crystal pixel 20 is in the original state. Erase by returning to. Further, in the partial erasing of FIG. 2D, a low voltage is applied to the pair of transparent conductive films 15 and the pixel 20 of the liquid crystal is irradiated with a laser beam, so that the pixel 2
Erase by resetting 0 to the original state.

Next, the main part of the liquid crystal display device will be described with reference to FIG.

First, the liquid crystal element 7 includes the above-mentioned liquid crystal panel 13 and the liquid crystal block 2 constituting the liquid crystal panel holding means.
It is composed of three blocks, 2, 23. And
The liquid crystal blocks 22 and 23 are composed of metal cases 24 and 25 made of aluminum or the like and glass plates 26 and 27, respectively. , 27, the liquid crystal block 23 is integrally coupled to the liquid crystal block 22 by a plurality of screws 28. And
A special liquid is sealed between the liquid crystal blocks 22 and 23.

Next, the liquid crystal element 7 supplies electric power from the heater driving circuit 31 to the heating means such as the rod-shaped heater 30 embedded in the metal case 24 of the liquid crystal block 22 to heat the rod-shaped heater 30 to drive the liquid crystal block. The metal cases 24 and 25 of 22 and 23 are heated to keep the entire liquid crystal panel 13 warm.

At this time, the entire liquid crystal panel 13 is covered with the metal cases 24 and 25 of the liquid crystal blocks 22 and 23 and the glass plate 26.
If the liquid crystal block 13 is covered with 27 and a special liquid is sealed between the liquid crystal blocks 22 and 23, the liquid crystal panel 13 has a high heat retaining effect and the whole liquid crystal panel 13 can be kept warm.

Next, the liquid crystal element 7 includes a liquid crystal block 22.
Ambient temperature detecting means such as a resistance temperature detector 32 which is externally attached to the metal case 24 or the like and detects the ambient temperature which is the ambient temperature around the liquid crystal element 7, and the liquid crystal element 7 detected by the resistance temperature detector 32. The temperature correction circuit 33 and the amplifier 3 for controlling the heating temperature of the rod-shaped heater 30 according to the change of the ambient temperature of the
4 is attached to the temperature control circuit 35.

According to the temperature control circuit 35 of the liquid crystal display device constructed as described above, the temperature correction circuit 33 is provided with a negative temperature coefficient with respect to the ambient temperature of the liquid crystal element 7.

Therefore, if the ambient temperature rises, the heating temperature of the rod-shaped heater 30 is lowered, and if the ambient temperature is lowered, the heating temperature of the rod-shaped heater 30 is raised. 25 can be constantly heated and maintained at a constant temperature.

As a result, the liquid crystal panel 13 can always be maintained at the optimum temperature accurately regardless of the change in the ambient temperature of the liquid crystal element 7, and the thickness of the drawing line of the liquid crystal panel 13 can be accurately adjusted within the standard. Can be set.

Incidentally, in this liquid crystal display device, when the heating temperature of the rod-shaped heater 30 is set to 53 ° ± 0.1 °, the overheating temperature of the liquid crystal blocks 22 and 23 is 51 ° ± 0.
At 1 °, the temperature of the liquid crystal layer 14 of the liquid crystal panel 13 becomes 2 degrees.
It is maintained at 5 ° ± 0.1 °, and the thickness of the thin line of the drawing line is 200 μm within the standard dimension (150 to 250 μm).
I was able to maintain it accurately.

The above is a description of one embodiment of the present invention.
The present invention is not limited to the above embodiments, and various modifications can be made based on the technical idea of the present invention. For example,
The ambient temperature detecting means is not limited to the resistance temperature detector 32, and may be any one capable of detecting the ambient temperature and generating less self-heating, for example, a thermistor, a posistor, a diode or the like. Can be used. Similarly, the heating means is not limited to the rod-shaped heater 30.

[0027]

The liquid crystal display device of the present invention constructed as described above has the following effects.

According to the first aspect, the ambient temperature control means
By detecting the ambient temperature, which is the outside air temperature of the liquid crystal element, and controlling the heating temperature of the liquid crystal panel holding means, the heating temperature is lowered when the ambient temperature becomes high, and the heating temperature is raised when the ambient temperature becomes low. Since the liquid crystal panel holding means can always be heated and held at a constant temperature, the liquid crystal panel can always be kept at the optimum temperature regardless of the change in the ambient temperature. Therefore, the drawing line thickness of the liquid crystal panel can be accurately set within the standard, and
It is possible to relax the temperature conditions of the place where the liquid crystal display device is used.

According to a second aspect of the present invention, the entire liquid crystal panel is covered with a metal case and a glass plate, and the ambient temperature detecting means and the heating means of the temperature control means are attached to the metal case to enhance the heat retaining effect of the liquid crystal panel. As a result, the temperature of the liquid crystal panel can be kept uniform, and the temperature of the liquid crystal panel can be accurately controlled according to changes in the ambient temperature.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a liquid crystal panel.

FIG. 3 is a diagram illustrating an optical block of a liquid crystal display device.

[Description of Reference Signs] 1 semiconductor laser (laser light source) 7 liquid crystal element 8 metal halide lamp (projection means) 9 condenser lens (projection means) 10 projection lens (projection means) 13 liquid crystal panel 14 liquid crystal layer 16 glass substrate (transparent substrate) 22 , 23 Liquid crystal block (liquid crystal panel holding means) 24, 25 Metal case 26, 27 Glass plate 30 Rod-shaped heater (heating means) 31 Heater drive circuit 32 Resistance temperature detector (ambient temperature detection means) 35 Temperature control circuit (temperature control means) )

Claims (2)

[Claims] 1. A liquid crystal display device comprising a liquid crystal element on which an optical image is recorded by a phase change of the liquid crystal due to heat generated by irradiation of laser light, and a liquid crystal display device comprising means for projecting and displaying the optical image. A temperature control means for holding the temperature of the liquid crystal panel constant by detecting the ambient temperature of the liquid crystal element and controlling the heating temperature of the liquid crystal panel holding means. A liquid crystal display device comprising: 2. The liquid crystal panel holding means comprises a metal case and a glass plate for covering the entire liquid crystal panel, and the ambient temperature detecting means and the heating means of the temperature control means are attached to the metal case. Item 2. The liquid crystal display device according to item 1.