JPH04147129A - Liquid crystal exposure device - Google Patents

Abstract

PURPOSE:To perform linear exposure without any gap between dots by providing a liquid crystal shutter array consisting of two arrays of zigzag liquid crystal shutters, which have orthogonal polarizing directions of transmitted light, between each reflecting mirror and an exposure area. CONSTITUTION:The device is equipped with reflecting mirrors 5 - 7 which reflect respective polarized light beams toward linear exposure positions on a photosensitive recording medium 9 and the liquid crystal shutter array 8 formed by arranging the two zigzag arrays of liquid crystal shutters having the orthogonal polarizing directions of transmitted light. Parallel light is split by a polarization beam splitter 4 into a P polarized light beam 20 and as S polarized light beam 11 having the orthogonal polarizing directions; and the P polarized light beam 10 is reflected by reflecting mirrors 6 and 7 and passes through a liquid crystal shutter array having the same polarizing direction with the P polarized light beam 10 between the two liquid crystal shutter arrays 8 and the S polarized light beam is reflected by a reflecting mirror 5 and passes through a liquid crystal shutter array having the same polarizing direction with the S polarized light beam 11, so that the photosensitive recording medium 9 is irradiated and exposed linearly and alternately. Consequently, the photosensitive recording medium 9 is exposed linearly without any gap between dots and no image forming lens is required.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid crystal exposure device equipped with a liquid crystal shutter, and in particular, the present invention relates to a liquid crystal exposure device equipped with a liquid crystal shutter, and in particular, parallel light in two directions is applied to the LCD shutter to form a straight line with no gaps. The present invention relates to a liquid crystal exposure apparatus that performs exposure.

[Conventional technology]

In recent years, various liquid crystal display elements (LCDs) have been developed that utilize various electro-optic effects in liquid crystals to switch between light transmission and light blocking.
) shutter has been developed.

Here, among the LCD shutters, a twisted nematic (TN) type LCD shutter will be explained. This TN type LCD shutter is made up of a plurality of liquid crystal light modulation elements arranged, and in each liquid crystal light modulation element, the liquid crystal is formed by two transparent electrode substrates (outside) and two sheets having uniform linear grooves. It is sandwiched between an alignment film (inner side). When no voltage is applied between the transparent electrodes, the liquid crystal molecules assume a specific alignment state according to the force regulated by the grooves of the alignment films, but the groove directions of the two alignment films are mutually Because they are shifted by 90 degrees, the liquid crystal molecules exhibit a twisted structure in the long axis direction of the molecules.
The alignment of liquid crystal molecules is twisted by 90 degrees between both alignment films.

When the TN type liquid crystal light modulation element in this state is sandwiched between two polarizing plates whose polarization directions are perpendicular to each other, and a light beam is incident from one of the polarizing plates, the light beam becomes linearly polarized light at the first polarizing plate. While this linearly polarized light travels through the liquid crystal, due to the birefringence of the liquid crystal molecules and the above-mentioned 90 degree twisted alignment structure,
The polarization direction of the above linearly polarized light is rotated by 90 degrees. As a result, the polarization direction of the linearly polarized light matches the polarization direction of the other polarizing plates, and the linearly polarized light is emitted as is. However, when a voltage is applied between the transparent electrodes, the liquid crystal molecules are forcibly aligned in the direction of the electric field, so that the above-mentioned 90 degree twisted alignment structure of the liquid crystal molecules is not formed. Therefore, the linearly polarized light incident from one polarizing plate reaches the other polarizing plate without rotation of the polarization direction, and when it is output, the polarization direction of the linearly polarized light and the polarization direction of the other polarizing plate are orthogonal and the light is blocked. be done.

The switching between light transmission and light blocking as described above is performed by applying a voltage between the transparent electrodes. By arranging a plurality of liquid crystal light modulation elements, a shutter with high response speed becomes possible.

Focusing on the characteristics of such LCD shutters, we
Various liquid crystal exposure devices using shutters have been developed. Normally, this LCD shutter has a wiring pattern formed around the liquid crystal pixels, and this serves as a black mask that blocks light, so when line exposure is performed using this, there are no gaps between dots. It is common practice to perform staggered exposure by using an LCD shutter array in which liquid crystal pixels are arranged in two rows in a staggered manner, and by forming an image on a photosensitive recording medium with an imaging lens such as a SELFOC lens array. Ta.

[Problem to be solved by the invention]

However, when exposing a photosensitive recording medium in a staggered manner as in the conventional example above, adjacent liquid crystal pixels are separated by a certain distance with respect to the moving direction of the photosensitive recording medium, so image information is not stored. It is necessary for the host computer to read data of different lines every other line from the RAM provided in the display and write the data to the LCD shutter array, which makes this data control quite difficult. Moreover, since an imaging lens such as a SELFOC lens array is used, there is a problem in that the apparatus becomes expensive.

The present invention has been made to solve the above-mentioned problems, and is capable of exposing dots in a straight line on a photosensitive recording medium without gaps between them, and also eliminates the need for an imaging lens such as a Selfoc lens array. The purpose is to provide equipment.

[Means to solve the problem]

In order to achieve this object, a liquid crystal exposure apparatus of the present invention exposes a photosensitive recording medium based on an image signal. a polarizing beam splitter that separates the and S-polarized light beams into mutually orthogonal polarized light beams, a reflecting mirror that reflects each of the polarized light beams toward a linear exposure position on the photosensitive recording medium, and each of the reflecting mirrors and the exposure area; It is equipped with a liquid crystal shutter array in which two rows of liquid crystal shutters are arranged in a staggered manner, and the polarization directions of transmitted light are orthogonal to each other.

[Effect]

According to the present invention having the above configuration, parallel light from a light source is separated by a polarizing beam splitter into a P-polarized light beam and an S-polarized light beam whose polarization directions are orthogonal to each other, and this P-polarized light beam is reflected by a reflection mirror and is reflected by a liquid crystal display. Among the two rows of liquid crystal shutters in the shutter array, the S-polarized light passes through the liquid crystal shutter row that has the same polarization direction as the P-polarized light, and the S-polarized light is reflected by the reflection mirror and passes through the liquid crystal shutter row that has the same polarization direction as the S-polarized light. The light passes through the photosensitive recording medium and is irradiated in a straight line every other photosensitive recording medium, thereby performing exposure. As a result, it is possible to expose the photosensitive recording medium in a straight line with no gaps between dots, and it is also possible to eliminate the need for an imaging lens such as a SELFOC lens array.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

The liquid crystal exposure apparatus of the present invention includes a halogen lamp 1 as a rod-shaped light source and a reflector 2 that reflects the light emitted from the halogen lamp 1. The reflected light is converted into parallel light by a condenser lens 3 and directed toward a polarizing beam splitter 4.

This polarizing beam splitter 4 is for separating the parallel light incident from the condenser lens 3 into a P polarized light beam 10 and an S polarized light beam 11 having different 90° vibration planes.

One of the S-polarized light beams 11 separated by the polarizing beam splitter 4 is reflected by the S-polarized light reflection mirror 5 and enters a liquid crystal (LCD) shutter array 8 disposed above the photosensitive recording medium 9. It is incident at an angle θ. The other P-polarized light beam 10 is sequentially reflected by the first P-polarized light reflection mirror 7 and the second P-polarized light reflection mirror 6, and is reflected by the S
The light is incident on the LCD shutter array 8 from the side opposite to the polarization line 11 at the same angle of incidence θ.

Here, each of the reflecting mirrors 5 and 6 is adjusted so that the optical path length of the P polarized light beam 10 and the optical path length of the S polarized light beam 11 are the same, so that the light amount is the same, and the angle of incidence θ for both is the same. .7 position is adjusted.

As shown in FIG. 2, the LCD shutter array 8 has two rows of liquid crystal elements arranged in a staggered pixel arrangement, and each row has a P-polarized light beam 10 that passes light having the same vibration plane as the P-polarized light beam 10. A polarizing plate 12 and an S-polarizing plate 13 that transmit light having the same vibration plane as the S-polarized light beam 11 are arranged. In addition, a black mask 15 is placed around each liquid crystal element to prevent leakage current.
The light is blocked by Then, the S-polarized light beam 11 reflected by the S-polarized light reflection mirror 5 passes through the S-polarizing plate 13 of the LCD shutter array 8 and hits every other exposed point 14a among the transmission points 14 of the photosensitive recording medium 9. reach. In addition, the P-polarized light beam 1 reflected by the second P-polarized light reflection mirror 6
0 passes through the P polarizing plate 12 of the LCD shutter array 8 and reaches every other exposure position 14b among the transmission points 14 of the photosensitive recording medium 9.

That is, the P-polarized light ray 10 hits the row with the P-polarizer 12 as parallel light at an incident angle θ, while the S-polarized light 11 hits the row with the S-polarizer 13 as parallel light at an incident angle θ from the opposite side. However, since the vibration planes of the respective polarized light beams 10° and 11 differ by 90°, different polarizing plates, for example, the P-polarized light beam 10
does not pass through the S polarizing plate 13. Furthermore, since a black mask 15 is provided on the surface of the LCD shutter array 8 to block light from areas other than the liquid crystal pixels, uniform light is exposed in a straight line onto the photosensitive recording medium 9 through the LCD shutter array 8. Ru.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit thereof.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention, it is possible to expose dots on a photosensitive recording medium in a straight line without gaps between dots, thereby facilitating data control. Furthermore, since an imaging lens such as a SELFOC lens array is not required, the cost of the apparatus can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a liquid crystal exposure apparatus, and FIG. 2 is an enlarged perspective view of a main part of an exposure section. 1...Halogen lamp (light source), 3...Condenser lens, 4...Polarizing beam splitter, 5.6.7.
・・Reflection mirror 8・・LCD shutter array 9・
...Photosensitive recording medium, 10...P polarized light beam, 11...S
Polarized light beam, 12...P polarizing plate, 13...S polarizing plate, 1
4...Exposed area.

Claims (1)

[Claims] A liquid crystal exposure device that exposes a photosensitive recording medium based on an image signal, the liquid crystal exposure device comprising: a light source that produces parallel light; A polarizing beam splitter that separates the polarized light beams into polarized light beams, a reflecting mirror that reflects each of the polarized light beams toward a linear exposure position on the photosensitive recording medium, and a polarization direction of the transmitted light between each of the reflecting mirrors and the exposure area. 1. A liquid crystal exposure device comprising: a liquid crystal shutter array having two rows of liquid crystal shutters arranged in a staggered manner with orthogonal to each other.