JPH04146427A - Liquid crystal exposing device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a polarizing plate caused by heat by sending cooling air to the parts of a liquid crystal display panel and respective polarizing plates by an air sending means and removing heat generated by the irradiation of light. CONSTITUTION:A cooling fan 9 being the air blower means for sending the cooling air to the part between the liquid crystal display panel 7 and the respective polarizing plates 8a and 8b is disposed. The cooling air is sent to the parts of the panel 7 and the respective polarizing plates 8a and 8b so as to remove the heat generated by the irradiation of the light, so that the deterioration of the polarizing plates 8a and 8b caused by the heat is prevented and the lives of the plates 8a and 8b are prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal exposure apparatus, and more particularly to a liquid crystal exposure apparatus for exposing a desired image onto a photosensitive recording medium using a liquid crystal display panel.

[Conventional technology]

In recent years, for example, twisted nematic shutters have been used as shutters to switch between transmitting and blocking light.
TN) type liquid crystal display panels have been developed, and conventionally, such liquid crystal display panels are used to expose the image displayed on the liquid crystal display panel to a photosensitive recording medium using transmitted light. An exposure device is used.

Such a liquid crystal display panel has a plurality of liquid crystals sandwiched between two transparent electrode substrates and two alignment films having uniform linear grooves and arranged in a direction perpendicular to each other. It is formed by arranging liquid crystal light modulation elements, and in this liquid crystal light modulation element, the liquid crystal molecules have a twisted structure of 90° in the long axis direction of the molecules due to the groove direction of the two alignment films. Therefore, the alignment of liquid crystal molecules is twisted by 90° between both alignment films. Further, each of these liquid crystal light modulation elements is sandwiched between two polarizing plates whose polarization directions are perpendicular to each other.

When light is made incident from one of the polarizing plates, the light becomes linearly polarized by the first polarizing plate.

When no voltage is applied between the transparent electrodes, while the linearly polarized light travels through the liquid crystal, the polarization direction of the linearly polarized light changes due to the birefringence of the liquid crystal molecules and the 90° twisted alignment structure. The linearly polarized light is rotated by 90 degrees to match the polarization direction of the other polarizing plates, and the linearly polarized light is emitted as is. Furthermore, when a voltage is applied between the transparent electrodes,
The liquid crystal molecules are forcibly aligned in the direction of the electric field, and the above-mentioned 90° twisted orientation structure of liquid crystal molecules is no longer formed. Since the polarization direction of the linearly polarized light and the polarization direction of the other polarizing plate are perpendicular to each other, the linearly polarized light is not emitted but is blocked.

In a liquid crystal exposure apparatus using such a liquid crystal display panel, an image is formed by the liquid crystal display panel based on predetermined image data, and light from a light source that transmits only the part other than the image is transmitted through an optical lens. By forming an image on a photosensitive recording medium, a desired image is exposed.

[Problem to be solved by the invention]

However, in the conventional liquid crystal exposure apparatus described above, a halogen lamp or the like with a relatively large amount of light is used as the light source for exposure, so that the light from the light source that is not in the polarization direction of the polarizing plate is used to display the liquid crystal display. The light does not enter the panel and becomes heat, and even if the light passes through the liquid crystal display panel, light other than the polarization direction of the other polarizing plate is similarly not emitted and becomes heat. In this case, since the polarizing plate is extremely weak against heat, the polarizing plate easily deteriorates.
This has the problem of shortening the life of the polarizing plate.

Furthermore, since the polarizing plate that generates heat is closely attached to the liquid crystal display panel, there is a problem in that heat is transferred to the liquid crystal display panel, causing deterioration of the liquid crystal element.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a liquid crystal exposure apparatus that can reduce the amount of heat generated in the polarizing plate portion and prevent deterioration of the polarizing plate and the liquid crystal display panel. This is the purpose.

[Means to solve the problem]

In order to achieve the above object, a liquid crystal exposure apparatus according to the present invention includes:
A liquid crystal display panel that forms an image based on desired image data is provided, and polarizing plates that polarize light are provided on both sides of this liquid crystal display panel, and light is transmitted from the light source through the liquid crystal display panel and each polarizing plate. In a liquid crystal exposure device that performs exposure by irradiating a photosensitive recording medium with light, the liquid crystal electro-optical element and each polarizing plate are arranged with a predetermined gap, and the liquid crystal display panel and each polarizing plate are arranged near the liquid crystal display panel and each polarizing plate. It is equipped with a blower means for blowing cooling air.

[Effect]

According to the present invention, cooling air is blown to the liquid crystal display panel and each polarizing plate portion by the air blowing means to remove heat generated by light irradiation, thereby reliably preventing deterioration of the polarizing plate due to heat. In addition, since the liquid crystal display panel is arranged with a predetermined gap from each polarizing plate, the heat generated from the polarizing plate is transferred to the liquid crystal display panel. It will not be transmitted to the display panel, and deterioration of the liquid crystal element can be reliably prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

1 and 2 show an embodiment of a liquid crystal exposure device according to the present invention. A liquid crystal exposure device 2 is disposed inside a liquid crystal printer 1. ,
It has a halogen lamp 3 as a light source. Moreover, above this halogen lamp 3, this halogen lamp 3
A reflecting plate 4 is disposed to reflect the irradiated light downward from the halogen lamp 3, and a condenser lens 5 is disposed below the halogen lamp 3 to convert the emitted light from the halogen lamp 3 into parallel light. There is. An infrared cut filter 6 is disposed below the condenser lens 5, and a liquid crystal display panel 7 is disposed below this infrared cut filter 6. On the upper and lower sides of this liquid crystal display panel 7, there are rear polarizing plates 8.
The front polarizing plates 8a and 8b are each disposed with a predetermined gap from the liquid crystal display panel 7, and the polarizing plates 8a and 8b are disposed such that their polarization directions are perpendicular to each other.

The liquid crystal display panel 7 is formed by sandwiching a liquid crystal between two transparent electrode substrates via an alignment film in which the directions of uniform linear grooves are perpendicular to each other. When no current is applied, the light irradiated from the condensing lens 5 to the liquid crystal display panel 7 becomes straight light at the rear polarizing plate 8a, and then becomes linear light due to the birefringence of the liquid crystal molecules and the 90° twist of the alignment film. Due to the alignment structure, the light beam becomes a straight light whose polarization direction is rotated by 90 degrees, and the polarization direction coincides with that of the front polarizing plate 8b, so that the straight light is emitted as is. When electricity is applied to the transparent electrode, the liquid crystal molecules of the liquid crystal display panel 7 are forcibly aligned in the direction of the electric field, and the twist of the liquid crystal molecules is eliminated, so that the light incident on the liquid crystal display panel 7 from the rear polarizing plate 8a is , is emitted as it is, and this linear light is no longer emitted because its polarization direction is different from that of the front polarizing plate 8b.

Moreover, in this embodiment, the liquid crystal display channel 7 and each polarizing plate! A cooling fan 9 serving as a blowing means for blowing cooling air is disposed between 3a and 8b.

Further, inside the liquid crystal printer 1, a video I/F circuit 10 for inputting image data signals from the outside is arranged, and this video I/F circuit 10 converts analog image data signals into digital An A/D conversion circuit 11 for converting into a signal is connected. Connected to this A/D conversion circuit 11 is a video RAM 12 that separates and writes the image data signal digitized by the A/D conversion circuit 11 into red, green, and blue. , an LCD drive controller 13 is connected which causes the liquid crystal display panel 7 to form images of each color based on the gradation data of the images of each color written in the video RAM 12.

Further, below the liquid crystal display panel 7, a filter unit 14 consisting of color filters 14R914G and 14B is arranged to separate the light transmitted through the liquid crystal display panel 7 into single colors of red, green, and blue. An imaging lens 15 is disposed below the filter unit 14 to form an image from the liquid crystal display panel 7 on a predetermined exposure position.

A microcapsule paper 16 is disposed at the exposure position, and the microcapsule paper 16 contains a dye precursor or the like that reacts with a color developer on the surface of a long support. It is formed by applying multiple microcapsules. In addition, unexposed microcapsule paper 1
6 is housed in a light-shielding cartridge 18 while being wound around a cartridge shaft 17. On the downstream side of the exposure position of the microcapsule paper 16, a developer paper is placed on the latent image formed by exposure. A pair of pressure rollers 19, 19 are provided for performing pressure development in an overlapping state. Further, below the pressure roller 19, a winding pongee 20 for winding up the exposed and pressure-developed microcapsule paper 16 is disposed.

Further, above the pressure roller 19, a plurality of color developing papers 2
A paper feed cassette 22 in which the color developer paper 21 is stacked and accommodated therein is detachably attached, and the color developer paper 21 has a color developer coated on the surface of the support and is encapsulated in the microcapsules of the microcapsule paper 16. It develops color by reacting with a dye precursor. Further, above one end of the paper feed cassette 22, a half-moon roller 23 is provided for taking out the color developing paper 21 one by one.
is arranged near the paper feed cassette 22,
The developer paper 21 taken out by the half-moon roller 23 is transferred to the pressure roller 19 at a timing such that the tip of the developer paper 21 and the tip of the latent image on the microcapsule paper 16 are aligned.
A paper feed roller 24 is provided to convey the paper.

Further, on the downstream side of the pressure roller 19, a heat fixing device 2 is provided.
5 is arranged, and inside this heat fixing device 25,
A heater 26 and a conveyor belt 27 for conveying the developing paper 21 after pressure development are provided.

Next, the operation of this embodiment will be explained. First, external image data is input to the liquid crystal exposure device 2 by the video I/F circuit 10, and this image data is input to the A/D conversion circuit 1.
1 is digitized, separated into red, green, and blue, and written into the video RAM 12.

Then, by operating a print start key (not shown), the LCD drive controller 13 is operated, thereby causing the liquid crystal display panel 7 to first form an image corresponding to the red image data signal. Meanwhile, the halogen lamp 3 is turned on, and the red filter 14R of the filter unit 14 is placed below the liquid crystal display panel 7.

The light from the halogen lamp 3 is efficiently focused by the reflection plate 4 and the condensing lens 5 and becomes parallel light.
The light passes through the infrared cut filter 6 and enters the rear polarizing plate 8a. Here, light in a direction other than the polarization direction does not enter the liquid crystal display panel 7 and becomes heat. On the other hand, the light in the polarization direction is incident on the liquid crystal display panel 7, and the light that has passed through the liquid crystal display panel 7 is irradiated onto the front polarizing plate 8b. Of the light irradiated to the front polarizing plate 8b, the light whose polarization direction is the same as that of the front polarizing plate 8b due to the twisting of the liquid crystal element when no voltage is applied is transmitted through the front polarizing plate 8b, but when the voltage is applied, the light is twisted. Since the polarization direction of the remaining light is 90° different from that of the front polarizing plate 8b, the light is blocked by the front polarizing plate 8b and becomes heat.

In this case, in this embodiment, the cooling fan 9 is driven to blow cooling air to the liquid crystal display panel 7 and each of the polarizing plates 8a and 8b to remove the heat generated by the light irradiation. ing.

The polarized light beam that has passed through the front polarizing plate 8b passes through the red filter 14R and is imaged onto the microcapsule paper 16 by the imaging lens 15 for exposure. An image is formed.

When the red exposure is completed, the filter unit 14 is driven to replace the red filter 14R with the green filter 14G, and the LCD drive controller 13 switches the red image on the liquid crystal display panel 7 to a green image. Exposure is performed in the same way. Further, the blue image is similarly exposed to light, and when the exposure of the three colors is completed, a color latent image is formed on the microcapsule paper 16.

Next, the microcapsule paper 16 is conveyed in the direction of the pressure roller 19 by driving the winding shaft 20 and the pressure roller 19, while the developer paper 21 is fed by driving the half-moon roller 23. The color developing paper 21 is taken out one by one from the paper cassette 22, and the paper feed roller 24 transfers it to the pressure roller 19.
Transport to.

Then, the exposed surface of the microcapsule paper 16 and the color developer paper 21
Pressure roller 19 with the color developer coated surface of
The latent image on the microcapsule paper 16 is transferred to the color developing paper 21.

After passing through the pressure roller 19, the developer paper 21 is separated from the microcapsule paper 16 and conveyed to a heat fixing device 25.
It is wound up. The color developing paper 21 after separation is further conveyed by the conveyor belt 27 and is then heated to a heater 26.
The image is heated to promote color development, and after a desired color image is formed, it is output to the outside.

Therefore, in this embodiment, the cooling fan 9 cools the liquid crystal display panel 7 and each polarizing plate 8a.

Since cooling air is blown to the portion 8b to remove the heat generated by the irradiation of the light, the polarizing plates 8a and 8b
Deterioration due to heat can be reliably prevented, and the polarizing plate 8
The lifespan of parts a and 8b can be significantly improved. Moreover, since the liquid crystal display panel 7 is arranged with a predetermined gap from each of the polarizing plates 8a and 8b, the polarizing plate 8a.

The heat generated from 8b is not transferred to the liquid crystal display panel 7, and deterioration of the liquid crystal element can be reliably prevented.

Note that the present invention is not limited to the above embodiments,
Various changes can be made as necessary.

For example, in this embodiment, a color filter is used to create a color liquid crystal exposure device, but the color filter may be omitted and a monochrome liquid crystal exposure device may be used.

〔Effect of the invention〕

As described above, the liquid crystal exposure apparatus according to the present invention uses the blowing means to blow cooling air to the liquid crystal display panel and each polarizing plate portion to remove heat generated by light irradiation. Deterioration due to heat can be reliably prevented, and the life of the polarizing plate can be significantly improved. Moreover, since the liquid crystal display panel is separated from each polarizing plate, the heat generated from the polarizing plates is not transferred to the liquid crystal display panel, and deterioration of the liquid crystal element can be reliably prevented. It has the following effects.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram showing an embodiment of a liquid crystal printer to which a liquid crystal exposure apparatus according to the present invention is applied, and Figure 2 is a perspective view of the liquid crystal display panel portion of Figure 1. 1...Liquid crystal printer, 2...Liquid crystal exposure device, 3...
・Halogen lamp, 5... Condensing lens, 6... Infrared cut filter, 7... Liquid crystal display panel, 8...
Polarizing plate, 9...Cooling fan, 10...Video I/F
Circuit, 11... A/D conversion circuit, 12... Video R
A.M. 13... LCD drive controller, 14... Filter unit, 15... Imaging lens, 16... Microcapsule paper, 19... Pressure roller, 21 River color developing paper,
25... Heat fixing device.

Claims (1)

[Claims] A liquid crystal display panel that forms an image based on desired image data is provided, and polarizing plates that polarize light are provided on both sides of this liquid crystal display panel, and light is transmitted from the light source through the liquid crystal display panel and each polarizing plate. In a liquid crystal exposure apparatus that performs exposure by irradiating a photosensitive recording medium with light, the liquid crystal exposure element and each polarizing plate are arranged with a predetermined gap, and the liquid crystal display panel and each polarizing plate are arranged near the liquid crystal display panel and each polarizing plate. A liquid crystal exposure apparatus characterized in that a blowing means for blowing cooling air is provided.