JPH06265927A - Liquid crystal spatial light modulator - Google Patents

Abstract

PURPOSE:To improve the productivity by providing an area of twisted orientation and an area of parallel orientation and providing a means which optically connects these areas to eliminate a need of a special optical system for alignment. CONSTITUTION:A one-dimensional prism array 107 is arranged behind a liquid crystal panel 100, and a polarizing plate 101 is arranged on the opposite side. Arrays of ECB(electric field controlled birefringence) cells and TN(twisted nematic) cells of homogeneous orientation are alternately arranged, and every two of respective cells are paired and are connected optically like a prism. They are orientated in one direction on the TFT element substrate side but have the orientation direction changed every array on the counter substrate side. That is, an orientating film 105 is applied on the counter substrate to perform the orientation treatment for ECB cells, and an orientating film 110 is applied throughout over the film 105 to perform the orientation treatment for TN cells, and parts of ECB cells are etched, and applied orientating films are removed from behind to form areas of TN and ECB.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal spatial light modulator capable of independently modulating the amplitude and phase of light.

[0002]

2. Description of the Related Art A conventional liquid crystal spatial light modulator has a TN panel 303 and an ECB panel 302 arranged in series, as shown in FIG. 3 ('92 Autumn Meeting of the Applied Physics Academic Conference, Proceedings). , 17p-N-2).

[0003]

However, the conventional liquid crystal spatial light modulator has the following problems. While trying to align the positions of the two liquid crystal panels while looking at the alignment mark with a microscope, the glass substrate (thickness 1m
Since it is 2 mm from m), it is impossible to focus on both marks, and accurate alignment cannot be performed. For this reason,
After aligning the parallel light vertically so that the moire disappears, the pattern is displayed to check the correspondence of the pixels.A special optical system is required, which is suitable for mass production. There was a problem of not having. The present invention solves such a problem, and an object thereof is to provide a high-performance liquid crystal spatial light modulator by a simple means.

[0004]

A first liquid crystal spatial light modulator according to the present invention is provided with regions of twist alignment and regions of parallel alignment, and means for optically connecting these regions. And

A second liquid crystal spatial light modulator of the present invention is characterized in that, in the first liquid crystal spatial light modulator, the connecting means is a prism array.

[0006]

The details of the present invention will be described below with reference to Examples.

(Embodiment 1) FIG. 1 shows the configuration of a liquid crystal spatial light modulator of the present invention. A one-dimensional prism array 107 is provided behind the liquid crystal panel 100, and a polarizing plate 101 is provided on the opposite side.
Were arranged respectively. The arrangement of pixels of this liquid crystal panel is shown in FIG. ECB (electric field control birefringence) cells 202 and TN (twisted nematic) cells 201 having a homogeneous orientation are alternately arranged in columns. These are paired two by two and are optically connected by a prism. In this embodiment, the pixels of the liquid crystal panel are vertically long, and the ECB
The set of TN and TN is almost square.

Coherent light 1 that has passed through the polarizing plate 101
12, 113 become linearly polarized light and enter the ECB or TN cell. The ECB cell changes the phase of the light polarized in the direction of the liquid crystal director without changing the polarization state of the light. Since the TN cell changes the polarization state of light,
When the light passes through the polarizing plate again, its amplitude changes.
The light 112 incident from the ECB cell is first phase-modulated by the ECB cell, folded back by the prism 107, and incident on the TN cell. This light becomes elliptically polarized light while passing through the TN cell, and the amplitude changes again when passing through the polarizing plate 101. With this, the amplitude and phase could be modulated. On the other hand, the light 113 incident from the TN cell is first elliptically polarized by the TN cell. Then, it is folded back by the prism 107 and enters the ECB cell. The ECB cell phase-modulates only the polarization component parallel to the director and does not change the polarization state. When this light passes through the polarizing plate 101 again, the amplitude changes. With this, the amplitude and phase could be modulated similarly to the light incident from the ECB. Since the TN cell also changes the phase, this is EC
It was corrected by the data input to the B cell.

In order to reduce the influence of diffraction by the pixel, d <a (2x-a) / 4nλ. Here, d is the thickness of the counter substrate 106, a is the size of the opening (smaller when the length and width are different), x is the pixel pitch (the same direction as a), n is the refractive index of the optical path, and λ is the wavelength of light. Yes (see Figure 2). This is a diffraction image (sinc) of a rectangular aperture.
This is a condition that the first zero of (function) does not enter the adjacent pixel.
In this embodiment, the horizontal pixel pitch is 40 μm, the opening size is 30 μm, and the thickness of the counter substrate is about 0.4 mm.

The liquid crystal panel used in this embodiment is of the TFT driving type, and the TFT element substrate 102 is on the light incident side. T
In order to prevent malfunction of the FT element 109, a light shielding mask 108 is arranged below the TFT element (light incident side).

The TFT element substrate side is oriented in one direction, and the counter substrate side is changed in orientation for each row. That is,
An alignment film 105 is applied on the counter substrate, and an alignment process for an ECB cell is performed first (rubbing parallel to the TFT element substrate). Next, an alignment film 110 is applied to the entire surface from above and alignment treatment for the TN cell is performed (rubbing is performed at right angles to the rubbing direction of the TFT element substrate). After this, EC
The B cell portion is etched to remove the alignment film applied later. Thus, the TN and ECB regions were formed.

In the liquid crystal spatial light modulator of the present invention, only the alignment of the prism array needs to be performed, and it is not necessary to check the correspondence of pixels as in the conventional case. For this reason, no special optical system for alignment is required, and productivity is improved.

It is also possible to form the prism array directly on the counter substrate. In this case, the assembly becomes easier.

[0014]

According to the present invention, when the liquid crystal spatial light modulator is manufactured, only the alignment of the prism array need be performed, and it is not necessary to check the correspondence of the pixels as in the conventional case. Therefore, no special optical system for alignment is required, and the effect of improving productivity can be obtained. Further, if the prism array is directly formed on the counter substrate of the liquid crystal spatial light modulator, the manufacturing becomes easier.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of a liquid crystal spatial light modulator of the present invention.

FIG. 2 is a top view showing an arrangement of pixels of the liquid crystal spatial light modulator of the present invention.

FIG. 3 is a side view showing a configuration of a conventional liquid crystal spatial light modulator.

[Explanation of symbols]

 100 liquid crystal panel 101 polarizing plate 102 TFT element substrate 103 alignment film 104 liquid crystal 105 alignment film 106 counter substrate 107 prism array 108 light-shielding mask 109 TFT element 110 alignment film 111 light-shielding mask 112 coherent light 113 coherent light 201 TN cell 202 ECB cell 301 polarization Plate 302 ECB panel 303 TN panel 304 Polarizing plate

Claims (2)

[Claims] 1. A liquid crystal spatial light modulator comprising a twisted alignment region and a parallel alignment region, and means for optically connecting these regions. 2. The liquid crystal spatial light modulator according to claim 1, wherein the connecting means is a prism array.