Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2000-01-18
2003-11-18
Saras, Steven (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S055000, C345S031000, C345S108000
Reexamination Certificate
active
06650309
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a light modulation element for changing the position of a needle by an electrostatic stress for executing light modulation, an array-type light modulation element, a drive method thereof, and a flat-panel display unit.
2. Description of the Related Art
A light modulation element is available for controlling the amplitude (strength), phase, travel direction, etc., of incident light for processing and displaying an image, pattern data, etc. One of the light modulation elements is a liquid crystal light modulation element using the electro-optic effect of liquid crystal. The liquid crystal light modulation element preferably is used with a liquid crystal display of a thin flat-panel display unit. The liquid crystal display has a structure wherein oriented liquid crystal is entered and sealed between substrates forming a pair of conductive transparent films and sandwiched between orthogonal deflecting plates. The liquid crystal display produces display by applying a voltage to the conductive transparent film for orienting the liquid crystal molecules in the long axis direction perpendicular to the substrate and changing the transmission factor of light from a backlight.
By the way, in the liquid crystal display, light from the backlight is allowed to pass through multiple layers of the deflecting plates, transparent electrodes, and color filter, thus the light use efficiency lowers. The high-grade liquid crystal display requires TFTs and liquid crystal must be sealed between two substrates and be oriented, thus it is difficult to provide a large screen. This is a disadvantage of the liquid crystal display. Further, since light is allowed to pass through between the oriented liquid crystal molecules, the viewing angle becomes narrow. This is another disadvantage of the liquid crystal display.
To solve such disadvantages, an electrostatically driven light modulation element is proposed. This light modulation element comprises an alternating pattern of a first shield section having a plurality of drive electrodes insulated from each other arranged in a predetermined spacing in a predetermined direction and a second shield section movable with positive and negative charges electrostatically induced, the first and second shield sections being placed on a transparent substrate. The voltage applied to the drive electrode is changed, whereby the relative position between the first and second shield sections is changed by an electrostatic stress between the first and second shield sections, thereby changing the transmission factor of light passing through therebetween for executing light modulation.
According to the electrostatically driven light modulation element, light from the light source is allowed to pass through only the transparent substrate, so that the light use efficiency can be raised and the light modulation elements can be easily put into an array by photolithography and etching and liquid crystal need not be poured or oriented, thus the manufacturing costs can be reduced and a large area can be easily provided.
However, in the electrostatically driven light modulation element in the related art described above, the displacement relationship between the applied voltage and the relative position between the first and second shield sections shows a hysteresis characteristic, thus generally the applied voltage to the drive electrode is changed binarily. Therefore, the drive method becomes so-called simple matrix drive for connecting scan signal electrodes and image signal electrodes to the first shield section and the second shield section, scanning the scan signal electrodes in sequence, and applying signal voltages corresponding to the scanned scan signal electrodes to the image signal electrodes. However, in the simple matrix drive, the condition of the voltages applied to the scan signal electrodes and the image signal electrodes depends on the hysteresis characteristic and is restricted. To enhance the image quality of contrast, etc., it becomes necessary to optimize the element structure and fit the hysteresis characteristic to the drive condition.
For binary simple matrix drive, a method of dividing one image display into fields, scanning, and changing the display time for providing gradation is possible as means for providing gradation. In this case, even in a drive method of weighting scan intervals in the fields for decreasing the number of scan times, the write scan time becomes short and a restriction is placed on design so that the light modulation element responds sufficiently to it.
In contrast, some liquid crystal displays adopt active matrix drive of adding active elements (TFT, etc.,) to intersection parts of an XY matrix and applying voltage to liquid crystal through the active elements. In the active matrix drive, scan voltage is applied to scan signal electrodes in sequence and the TFTs connected thereto are turned on in unison. At the same time, a signal is applied from image signal electrodes and charges are accumulated in capacitance of each pixel through the TFTs. At the termination of scanning one line, the TFTs are turned off and the charges accumulated in the pixel capacitance are retained (memorized) intact. According to the active matrix drive, applied voltage can be set as desired in a wide range and comparatively fast response speed and high contrast can be provided, so that high picture quality can also be provided particularly in a moving picture.
Thus, development of light modulation elements having a memory property while inheriting the advantages, thereby enabling active matrix drive is also demanded in the electrostatically driven light modulation elements.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a light modulation element provided with a memory property according to a simple/and low-cost configuration for enabling matrix drive capable of performing the operation at high speed and producing high-contrast display, an array-type light modulation element, a drive method thereof, and a flat-panel display unit.
To the end, in this invention, there is provided a light modulation element for performing electromechanical operation of generating a first electromechanical force for a needle for displacing the needle, thereby changing a transmission factor of light, the light modulation element comprising drive means for generating or canceling a second electromechanical force for the needle in a direction different from that of the first electromechanical force and holding or canceling the displacement state of the needle.
In the light modulation element, the light modulation operation is performed by the first electromechanical force and the displacement state of the needle can be held or canceled in response to the second electromechanical force generated by the drive means. Thus, a memory property can be provided for the light transmission factor of the light modulation element and the element structure enabling active matrix drive can be provided.
In the light modulation element in this invention, the electromechanical force is an electrostatic force produced by an electric field.
In the light modulation element, an electrostatic force acts because of the potential difference caused by voltage application and the first, second electromechanical force can be driven by the electrostatic force.
In the light modulation element in this invention, the electromechanical force is an electromagnetic force.
According to the light modulation element, first, second electro-mechanical force can be driven by the electromagnetic force generated by an electromagnet, etc.
In the light modulation element in this invention, the electro-mechanical force is a force produced by an electrostrictive strain effect.
According to the configuration, the first, second electromechanical force can be driven by the electrostrictive strain force of a piezo-element, etc.
In the light modulation element in this invention, the directions of the first and second el
Fuji Photo Film Co. , Ltd.
Nelson Alecia D.
Saras Steven
LandOfFree
Light modulation element, array-type light modulation... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Light modulation element, array-type light modulation..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Light modulation element, array-type light modulation... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3170440