KR20000032307A - Direct view type image displayer having tma module - Google Patents

Abstract

A direct view type image display device including a thin film mirror array (TMA) module is disclosed. The apparatus consists of pixels of a mirror for reflecting external light, and each mirror is deformed to a deformation size corresponding to the intensity of a corresponding one of a plurality of pixels displayed on the screen (TMA) Module and a black stripe array disposed at a predetermined distance from the thin film mirror array module and modulating the intensity of light reflected from each mirror of the thin film mirror array module. By using the thin-film mirror array module, the light efficiency can be increased and more information can be displayed than the display device using the liquid crystal display (LCD) module.

Description

Direct type image display device including thin film mirror array (TMA) module

The present invention relates to a direct view type image display apparatus, and more particularly, to a direct view type image display apparatus using a thin-film micromirror array-actuated (hereinafter referred to as TMA) module.

Optical path control devices or spatial light modulators for projecting optical energy onto the screen can be applied to various fields such as optical communication, image processing and information display devices. Typically, image processing apparatuses using such an optical modulator are classified into a direct view type image display device and a projection type image display device according to a method of displaying optical energy on a screen.

An example of a direct view image display device is a CRT (Cathode Ray Tube), which is a so-called CRT device, which has excellent image quality but increases in weight and volume as the size of the screen increases, leading to increased manufacturing costs. There is. Projection type image display devices include liquid crystal display (LCD), deformable mirror device (DMD) and AMA. Such projection image display apparatuses can be further divided into two groups according to their optical characteristics. That is, devices such as LCDs can be classified as transmit light modulators, while DMD and AMA can be classified as reflected light modulators.

Transmission optical modulators, such as LCDs, have a very simple optical structure, which makes them thinner, lighter in weight, and smaller in volume. However, the light efficiency is low due to the polarity of the light, there is a problem inherent in the liquid crystal material, for example, the response speed is slow and its inside is easy to overheat. In addition, the maximum light efficiency of existing transmission optical modulators is limited to a range of 1-2% and requires dark room conditions to provide acceptable display quality. Therefore, optical modulators such as DMD and Actuated mirror array (AMA) have been developed to solve the above problems.

Although DMD shows a relatively good light efficiency of about 5%, the hinge structure employed in the DMD not only causes serious fatigue problems, but also requires a very complicated and expensive driving circuit. The AMA reflects the light incident from the light source at a predetermined angle, and each mirror installed therein adjusts the luminous flux so that the reflected light is projected on the screen through an opening such as a slit or pinhole to form an image. Device. Therefore, its structure and operation principle are simple, and high light efficiency (more than 10% light efficiency) can be obtained compared to LCD or DMD. In addition, the contrast of the image projected on the screen is improved to obtain a brighter and clearer image.

Each actuator of the AMA generates a deformation in accordance with the electric field generated by the applied electric picture signal and the bias signal. As the actuator deforms, each of the mirrors mounted thereon is tilted. Therefore, the inclined mirrors reflect the light incident from the light source at a predetermined angle to form an image on the screen. As an actuator for driving the respective mirrors, a piezoelectric material such as PZT (Pb (Zr, Ti) O ₃ ), or PLZT ((Pb, La) (Zr, Ti) O ₃ ) is used. It is also possible to configure the actuator as electrostrictive material such as PMN (Pb (Mg, Nb) O 3).

These AMAs are classified into bulk and thin film types. Bulk AMA is disclosed in US Pat. No. 5,085,497 to Gregory Um et al. The bulk AMA is made by thinly cutting a multilayer ceramic to mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is built, and then processing by a sawing method and installing a mirror on the top. However, bulk AMA requires very high precision in design and manufacture, and has a disadvantage of slow response of the strained layer.

Accordingly, recently, a thin film mirror array (TMA) that can be manufactured using a semiconductor manufacturing process has been developed. For example, such a thin-film mirror array (TMA) is disclosed in Korean Patent Application No. 95-13353 (name of the invention: a method of manufacturing an optical path control device) filed by the applicant to the Korean Patent Office.

Thin-film mirror arrays (TMAs) are reflective optical modulators that use thin-film piezoelectric actuators in connection with microscopic mirrors, and have been developed to have uniformity of large-scale integration across more than 300,000 pixels of single-plate mirrors. come. The thin film mirror array TMA includes panels of 640 × 480 pixels representing red (R), green (G), and blue (B), respectively. The pixels are designed with a cantilever structure to maximize the surface area of the mirror to increase the light efficiency. Such a tilter structure includes an active matrix to which an image signal voltage is applied and a mirror operated by the applied signal voltage.

As described above, the direct view type image display device mainly uses a CRT (Cathode Ray Tube), but the small direct view type image display device such as a wrist watch, an instrument panel, or a mobile phone panel uses reflection using external light to reduce weight and volume. Type liquid crystal display (LCD) module. The liquid crystal display module is typically formed in a matrix form, in which pixels are arranged in a matrix in two directions perpendicular to each other and individually driven by a driving voltage to change optical characteristics of the liquid crystal. The driving voltage can be applied to the individual pixels by a simple matrix system, and a non-linear two-terminal element such as a metal-insulating metal (MIM) or a three-terminal switching element such as a TFT (thin film transistor) is arranged for each pixel. It may be applied to each pixel alternately by the active matrix system.

However, the reflective liquid crystal display module used in the small direct view type image display device has a disadvantage in that the driving speed is very slow compared to the active matrix system because it uses a passive matrix system that sequentially applies pulses. In addition, since the maximum light efficiency is low as about 1 to 2%, and the pixel pitch must be increased to minimize the light loss, the number of pixels per unit area of the screen is small and thus there is a small amount of information that can be displayed on the screen. In addition, since a dye is mixed with the liquid crystal to absorb light at the time of the OFF voltage, blue light appears on the screen, and a difference in viewing angles perceived by both eyes of the user is large.

Accordingly, it is an object of the present invention to provide a direct view type image display apparatus using a thin-film mirror array (TMA) module that can increase light efficiency and display more information than a conventional display apparatus using a liquid crystal display module. .

1 is a schematic view showing a direct-view image display device according to the present invention.

2A and 2B are plan views illustrating embodiments of a black stripe arrangement used in the device of FIG.

<Description of the code | symbol about the principal part of drawing>

100: direct image display device 102: black stripe

104: thin film mirror array (TMA) pixels

In order to achieve the above object, the present invention is composed of pixels of a mirror for reflecting external light, each mirror having a deformation size corresponding to the intensity of the corresponding one of the plurality of pixels displayed on the screen A black stripe disposed at a distance from the deformed thin film mirror array (TMA) module and the thin film mirror array (TMA) module to modulate the intensity of light reflected from each mirror of the thin film mirror array (TMA) module A direct view type image display apparatus including an array is provided.

According to the present invention, in order to display the desired information by modulating the intensity of light reflected from each mirror of the thin film mirror array (TMA) module, the black stripe array is arranged at a predetermined distance from the thin film mirror array module. Each black stripe of the black stripe array is arranged in the horizontal or vertical direction, and each of the black stripe and the mirrors of the thin film mirror array (TMA) module are alternately arranged.

Since the thin film type mirror array module is driven by an active matrix system, the direct view type image display device of the present invention has a faster driving speed than the device using the conventional reflective liquid crystal display device module. In addition, the thin-film mirror array module exhibits a high optical efficiency of about 10% and can reduce the pixel pitch compared to the liquid crystal display module, thereby increasing the number of pixels per unit area of the screen, thereby increasing the amount of information that can be displayed. In addition, by using the black stripe disposed in the horizontal direction, it is possible to minimize the difference in viewing angle that both eyes of the user perceives.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view showing a direct-view image display apparatus using a thin film mirror array (TMA) module according to the present invention.

Referring to FIG. 1, the direct-view image display apparatus 100 according to the present invention includes an array of black stripes 102a and a thin film mirror array (TMA) module 104.

The thin-film mirror array module 104 includes a plurality of mirror pixels 104a, 104b, 104c, ... for reflecting the irradiated light rays, and each mirror 104a, 104b, 104c, ... is provided thereunder. The intensity of the light beam is modulated in accordance with the electric signal applied to the actuator. That is, each of the mirrors 104a, 104b, 104c, ... is deformed to a deformation size corresponding to the intensity of one pixel among the plurality of pixels displayed on the screen.

Each black stripe 102a of the black stripe arrangement is formed of an optically opaque member. The flux of light rays passing between the black stripe 102a and the black stripe 102a controls the intensity of the light reflected from each of the mirrors 104a, 104b, 104c,... Of the thin film mirror array module 104. That is, the black stripe 102a array is provided for modulating the intensity of light reflected from the mirrors 104a, 104b, 104c, ... of the thin film mirror array module 104 to display a desired image on the screen.

2A and 2B are plan views illustrating embodiments of a black stripe arrangement.

2A and 2B, each black stripe 102a of the black stripe array 102 used in the direct view type image display device 100 of the present invention may be disposed in the vertical direction or in the horizontal direction. When the size of the thin-film mirror array module 104 is small, the light quantity difference occurs according to both eyes of the user light emitted from one point of the screen. That is, a difference in viewing angles occurs due to the deviation of both eyes of the user. Therefore, when the black stripe 102a is disposed in the horizontal direction as shown in FIG. 2B, light reflected from the mirror pixels adjacent in the horizontal direction with respect to one mirror pixel of the thin film mirror array (TMA) module 104. The light emitted from a point on the screen is felt by the same amount of light in both eyes of the user.

The operation principle of the direct-view image display device 100 according to the present invention having the above-described structure will be described in more detail as follows.

Light emitted randomly from the external light passes through the array of black stripes 102a and passes through the mirrors (hereinafter referred to as TMA pixels) 104a, 104b, 104c of the thin film mirror array (TMA) module 104. , ...). The TMA pixels 104a, 104b, 104c, ... are tilted at a predetermined angle in accordance with a signal applied to an actuator provided thereunder. The light rays reflected from the TMA pixels 104a, 104b, 104c, ... pass through the array of the black stripes 102a and display an image corresponding thereto on the screen. At this time, the path of the light rays reflected from the TMA pixels 104a, 104b, 104c, ... determines the intensity of the light rays passing through the black stripe 102a array. That is, the flux of light rays passing through the black stripe 102a array is controlled by the direction of the TMA pixels 104a, 104b, 104c, ... with respect to the black stripe 102.

In FIG. 1, the TMA pixel 104a on the right side shows an ON state, and light rays incident on the TMA pixel 104a from external light are reflected at a predetermined angle toward a specific front surface. Since the reflected light beams fall within the viewing angle of the user, a white image is displayed on the screen.

In FIG. 1, the TMA pixel 104b in the center shows an OFF state. Although the TMA pixel 104b reflects the light incident from the external light, the reflected light is out of the viewing angle of the user. It will appear black to the viewer.

In FIG. 1, the TMA pixel 104c on the left side also reflects the light rays incident from the external light, but since the reflected light rays are out of the viewing angle of the user, the TMA pixel 104c may appear black to the user looking at the screen.

Hereinafter, the relationship between the tilt angle of the TMA pixel and the viewing angle of the user will be described in detail.

The width of each black stripe 102a and the width of the TMA pixels 104a, 104b, 104c, ... are each referred to as 'a' and between each black stripe 102a and the TMA pixels 104a, 104b, 104c, ... When the distance is 'h', the angle θ of light reflected from the TMA pixels 104a, 104b, 104c,..., And transmitted through the black stripe 102a may be 0 and ± ArcTan (a /), respectively. h), ± ArcTan (2a / h), ± ArcTan (3a / h),... And so on.

At this time, the angle reaching the eyes of the user is ­ ArcTan (a / h) ~ + ArcTan (a / h), the light of the remaining angles should not enter the user's eyes. Light that can be used among the light incident on the TMA pixels 104a, 104b, 104c, ... has an angle of about ArcTan (2a / h) to ArcTan (4a / h).

In this case, light having an angle of ArcTan (2a / h) corresponds to ­ ArcTan (a / h) and light having an angle of ArcTan (4a / h) corresponds to ArcTan (a / h). Therefore, the tilt angle of the TMA pixels 104a, 104b, 104c, ... becomes ArcTan (1.5a / h).

For example, when the pitch a of the TMA pixel is about 100 μm, the tilting angle is about 5 °, and the distance h between the TMA pixel and the black stripe is about 1.7 mm, the viewing angle used by the user is about ± 3.3 °.

As described above, according to the direct view type image display device of the present invention, by using a thin film type mirror array (TMA) module driven by an active matrix system, the driving speed is increased compared to a device using a conventional reflective liquid crystal display (LCD) module. You can. In addition, the light efficiency can be increased, and the pixel pitch can be reduced compared to the liquid crystal display module, so that the number of pixels per unit area of the screen increases, thereby increasing the amount of information that can be displayed. In addition, by using the black stripe disposed in the horizontal direction, it is possible to minimize the difference in viewing angle that both eyes of the user perceives.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (2)

Consists of pixels of mirrors 104a, 104b, 104c, ... for reflecting external light, each mirror 104a, 104b, 104c, ... corresponding to one of a plurality of pixels displayed on the screen A thin-film mirror array (TMA) module 104 which is deformed into a deformation size corresponding to the intensity of a pixel of the pixel; And The intensity of light reflected from each of the mirrors 104a, 104b, 104c,... Of the thin film mirror array (TMA) module 104 is arranged at a predetermined distance from the thin film mirror array (TMA) module 104. And a black stripe array (102) for modulating. The black stripe array module of claim 1, wherein each black stripe 102a of the black stripe array 102 is disposed in a horizontal or vertical direction, and each black stripe 102a of the black stripe array 102 and the thin film mirror array module are disposed in the black stripe array 102. And the mirrors 104a, 104b, 104c, ... of 104 are arranged alternately with each other.