KR970003001B1 - Optical path regulating apparatus - Google Patents

Abstract

The light path adjusting device is embodied by using a shear strain feature of a piezoelectric ceramic. The device comprises: a substrate having MxN holes and conductive patterns in a matrix fashion on the surface of the lower portion thereof; a plurality of first and second actuators comprised of first and second strain portions each separated by means of first, second and third grooves, first and second signal electrodes exposed by means of the first groove to be connected to a part of the lower surface of the substrate through the holes, on the sides of the first and second strain portions, and first and second common ground electrodes exposed by means of the second groove to be connected the adjacent part through the surface crossed with the third groove, on the side of the first and second strain portions; an actuator array in which the first and second actuators constitute MxN unit pixels; and first and second reflection mirrors formed on the surfaces of the first and second signal electrodes.

Description

Light Path Control

1 is a cross-sectional view of a conventional optical path control device,

2 is a perspective view of an optical path adjusting device according to the present invention;

3 is a cross-sectional view of a unit pixel taken along line a-a of FIG.

* Explanation of symbols for main parts of the drawings

30: optical path control device 31: substrate

33: support portion 35: adhesive portion

37, 43: first and second deformation parts 39, 45: first and second signal electrodes

41,47: First and second common ground electrodes 42,48: First and second actuators

50: unit pixel 51,53: first and second reflecting mirror

55, 57, 59: first, second and third groove 61: hole

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical path adjusting device of a projection image display device, and more particularly, to an optical path adjusting device using characteristics of shear strain of piezoelectric ceramics.

An image display apparatus is classified into a direct view type image display apparatus and a projection type image display apparatus according to a display method. The direct view type image display device includes a CRT (Cathode Ray Tube). The CRT image display device has a good image quality, but there is a problem in that a large screen has an increase in weight and thickness, and a price is expensive. . Projection type image display apparatuses include a large crystal display (hereinafter referred to as an LCD). Such a large display LCD can be thinned to reduce its weight. However, such an LCD has a high loss of light due to a large loss of light due to a polarizing plate, and a thin film transistor for driving the LCD is formed for each pixel, so that there is a limit in increasing the aperture ratio (light transmission area).

In order to make up for the drawbacks of LCDs, a projection type image display device using Actuated Mirror Arrays (hereinafter referred to as AMA) was developed by Aura, USA. A projection image display device using AMA separates white light emitted from a light source into red, green, and blue light beams, and then reflects these light beams to reflectors inclined by the deformation of actuators, respectively. paths, and adjusts the amount of light beams to project on the screen to display an image. The AMA is classified into a one-dimensional AMA having an actuator of M × 1 and a two-dimensional AMA having an M × N according to the driving method. The actuator includes a deformable part and electrodes formed of a piezoelectric material or a warping material, and deforms when an electric field is generated to tilt the mirror on the top.

1 is a cross-sectional view of the optical path adjusting means 10 of the conventional projection display device.

The optical path adjusting means 10 includes a substrate 11, an actuator 14, and a reflector 23. The substrate 11 is made of an insulating material such as glass or Al ₂ O ₃ , and a conductive pattern 13 having a matrix shape is formed on a surface thereof. The actuator 14 is composed of the first and second deformable parts 15 and 17 and a signal and a common electrode material 19 and 21.

In the above, the first and second deformation parts 15 and 17 have an "L" shape and are disposed in a mirror image and mounted on the substrate 11 in an iron shape. The first and second deformable parts 15 and 17 are made of piezoelectric ceramics, and a reflector 23 is positioned on an upper portion thereof. Common electrodes 19 are formed on the surface of the first and second modified parts 15 and 17 facing the signal electrode 19. In this case, the first and second deformation parts 15 and 17 are polarized in one direction perpendicular to the signal electrode 19. The signal electrode 19 is electrically connected to the conductive line pattern 13, and the common electrodes 21 are connected to common electrodes of adjacent optical path control means by an external conductive pattern (not shown).

In addition, the signal and common electrodes 19 and 21 are formed of a conductive material such as metal, and deform the first and second deformation parts 15 and 17 when the signal voltage is applied. That is, for example, when a signal voltage is applied to the signal electrode 19 in a state in which the first deformation unit 15 is polarized in the direction of the second deformation unit 17, the polarization direction and the electric field direction are the first deformation unit 17. ) Does not coincide, but coincides in the second deformation unit 19. Therefore, the first deformable portion 15 contracts in the horizontal direction and expands in the vertical direction, and the second deformed portion 17 expands in the horizontal direction and contracts in the vertical direction. Therefore, the reflector 23 is inclined from the first deformable portion 15 toward the second deformable portion 17 to have an inclination angle. The inclination angle of the reflector 23 is in proportion to the length of the upper portion of the first and second deformations 15 and 17 and inversely proportional to the square of the thickness. Therefore, in order to increase the inclination angle of the reflector 23 to increase the optical path control range, the thickness of the upper portions of the first and second deformation parts 15 and 17 must be reduced or increased.

The optical path control means of the conventional projection image display device described above has a problem in that electrode formation is difficult because the temperature of the multilayer ceramic is higher than the melting point of the electrode. In addition, in order to increase the inclination angle of the reflector, the thickness of the upper part of the deformed portion has to be made thinner and the height has a problem that it is difficult to increase the directness.

An object of the present invention is to provide an optical path control apparatus having M x N pixels without forming a multilayer ceramic.

Another object of the present invention is to provide an optical path control apparatus that can increase the optical path control range.

The optical path control device according to the present invention for achieving the above object is a substrate having a plurality of support parts and a plurality of adhesive parts are staggered, the M × N holes formed by removing the adhesive parts and the matrix pattern of the wire pattern on the lower surface First and second grooves formed at a predetermined angle on the adhesive parts and the support parts connected to the holes and polarized perpendicularly to the substrate to form a body with the support parts; First and second deformed portions formed at right angles and separated by third grooves formed between the holes, and the first exposed portions by the first grooves so as to be connected to a part of the lower surface of the substrate through the holes. And first and second signal electrodes formed on side surfaces of the second deformed portions, and connected to neighboring ones through a surface of a portion intersecting the third grooves. Comprising a plurality of first and second actuators having a first and a second common ground electrode formed on the side of the first and second deformations exposed by the second grooves, these first and second actuators are M And an actuator array constituting N unit pixels, and first and second reflectors formed on the surfaces of the first and second signal electrodes.

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

2 is a perspective view of the optical path control device 30 according to the present invention.

The optical path control device 30 includes a substrate 31, first and second actuators 42 and 48, and first and second reflectors 51 and 53.

The substrate 31 is formed of piezoelectric ceramics such as BaTiO ₃ , PZT (Pb (Zr, Ti) O ₃ ), or PLZT ((Pb, La) (Zr, Ti) O ₃ ), and epoxy resin ( Adhesion portions 35 made of epoxy) or polymer are alternately formed. The substrate 31 has M x N holes 61, which are formed with a predetermined width along the x-axis by removing a portion of the adhesive portions 35 between the support portions 33. As shown in FIG. In addition, a conductive pattern is formed on the lower surface of the substrate 31 in the form of a mattress. The first and second actuators 42 and 48 are arranged alternately along the y axis to form an array. The first and second actuators 42 and 48 are respectively deformable portions 37 and 43 and signal electrodes. (39) (45) and common ground electrodes (41) (47). The deformation parts, that is, the first and second deformation parts 37 and 43 are polarized upward or downward along the z axis and protrude from the substrate 31 in a body with the support parts 33. . The first and second deformations 37 and 43 are inclined along the y axis and are formed in parallel with the first and second grooves 55 and 57 and the first and second grooves 55 formed in parallel along the x axis. 2M × N spaced apart by 57 and the third grooves 59 formed in parallel along the x-axis are arranged. The first and second deformations 37 and 43 are inclined by a predetermined angle to have a predetermined height from the substrate 31. The first grooves 55 are formed in the upper portion of the adhesive portion 35 and connected to the holes 61, and the second grooves 57 are formed in the upper portion of the support portion 33, and the lower surface thereof is formed on the substrate 31. It is formed to coincide with the upper surface of). Further, the holes 61 are formed between the first and second deformable portions 37 and 43 adjacent on the x axis.

Signal electrodes, that is, first and second signal electrodes 39 and 43, are formed on side surfaces of the first and second deformation parts 37 and 43 where the first grooves 55 are formed. The first and second signal electrodes 39 and 45 are sputtered or vacuum deposited so as to extend to the lower surface with gold (Au), silver (Ag), nickel (Ni), or chromium (Cr). Formed along the sides of the supports 33 exposed by the holes 61 and separated from each other. Common ground electrodes, that is, first and second common ground electrodes 41 and 47 are formed on the inner surface of the second grooves 57. The first and second common ground electrodes 41 and 47 are formed simultaneously with the first and second signal electrodes 39 and 45, and the second grooves 57 and the third grooves 59 cross each other. It is also formed at the bottom of the point where it is connected along the y axis.

In the above, the first and second actuators 42 and 48 on both sides of the first grooves 5 form a unit pixel 50. When the same size image signal having different polarities is applied to the first and second signal electrodes 39 and 45 in the pixels 50, the same size is applied to the first and second deformation parts 37 and 43. Branches are generated in the same direction as the electric field. Therefore, the first and second deformable parts 37 and 43 have a corner where the surface in the polarization direction and the side in the electric field direction abut, and the corner in the diagonal of the corner are sheared so that the first and second actuators are deformed. The 42 and 48 are changed at the same inclination angle. At this time, since the lower part of the first and second deformable parts 42 and 48 is fixed to the substrate 31 in one body, the upper surface of the first and second deformable parts 42 and 48 may be more deformed and remain parallel to the substrate 31. do. The degree of deformation of the first and second deformation parts 37 and 43 is proportional to the strength of the electric field.

The first and second reflecting mirrors 51 and 53 are formed on the surfaces of the first and second signal electrodes 39 and 45 by sputtering or vacuum deposition with aluminum (Al) or the like. The first and second reflectors 51 and 53 reflect the light beams incident through the holes 61 at the lower side of the substrate 31 twice to change the light path of the light beams to the unit pixels 50. It is not formed on the surfaces of the first and second signal electrodes 39 and 45 formed on the lower surface of the substrate 31. The first and second reflectors 51 and 53 reflect light beams incident by the deformation of the first and second actuators 42 and 48 to change the light path, and the light path has one reflector. It is twice as big as it is.

3 is a cross-sectional view of the unit pixel 50 taken along the line a-a of the optical path control device 30 of FIG.

The unit pixels 50 may include first and second actuators having an inclination angle θ ₁ and a vertical height h ₁ at left and right sides of a hole 61 having a width W formed in the substrate 31. (42) (48). In order to prevent the incident velocity of the light incident through the hole 61 from being reflected by the first and second reflectors 51 and 53 only once or three or more times, the first and second actuators ( The vertical height h ₁ of the 42 and 48 is defined by the width W ₁ of the hole 61 and the inclination angle θ ₁ of the first and second actuators 42 and 48.

In the above, the maximum distance through which the light beam incident from the lower side of the substrate 31 through the hole 61 can travel without being reflected by the first and second reflectors 51 and 53 is h ₂ , When the difference between the point where the light beam is first reflected by the first reflector 51 and the second reflector by the second reflector 53 is h ₃ , the first and second actuators 42 and 48 are 48. ) Is the height of h ₁

Becomes In the above, the maximum traveling distance (h ₂ ) of the incident light beam is

Also, the difference between the primary reflection point and the secondary reflection point h ₃ is

Becomes Then, when the angle between the primary reflected light flux and the substrate 31 is θ ₂ ,

Becomes Substituting Eq. (4) into Eq. (3)

Substituting this equation (5) into equation (1), the height h ₁ of the first and second actuators 42 and 48 is

Becomes The inclination angle θ ₁ of the first and second actuators 42 and 48 should satisfy the condition of 45 ° <θ ₁ <60 °. When the inclination angle θ ₁ of the first and second actuators 42 and 48 is less than or equal to 45 °, the incidence angles of the light beams incident on the first reflector 51 become 45 ° or greater, so that a part of the incident light beams is The first groove 5 does not proceed forward but proceeds backward. Further, if the inclination angle θ ₁ of the first and second actuators 42 and 48 is greater than or equal to 60 °, the secondary reflectors 53 in which the luminous fluxes reflected from the first reflector 51 are separated by an appropriate distance ω By not reaching and exiting the actuator light outlet 55, the purpose of the actuator scavenging cannot be achieved.

Further, the width W of the holes 61 is preferably from 30 to 110 m, preferably from 70 to 80 m. In the above, when the inclination angle θ ₁ of the first and second actuators 42 and 48 is 50 ° and the width W of the hole 61 is 77 μm, the first and the second The vertical height h ₁ of the two actuators 42 and 48 is 108 μm.

The driving of the single pixel 50 described above will be described. The first and second deformations 37 and 43 are polarized in either direction on the z axis. When an image signal of the same magnitude and opposite polarity is applied to the first and second signal electrodes 39 and 45, an electric field is applied to the first and second deformation parts 37 and 43. It is generated perpendicular to the electrodes 39, 43. That is, when a positive image signal is applied to the first signal electrode 51, an electric field is generated toward the first common ground electrode 41 perpendicular to the first signal electrode 39 in the first deformation part 37. do. In addition, a negative image signal equal to the magnitude of the image signal applied to the first signal electrode 39 is applied to the second signal electrode 45 so that the first deformation portion 37 is applied to the second deformation portion 43. The electric field is generated in the same direction as. In the above, the first and second deformations 37 and 43 are sheared in the + z direction to increase the inclination angle θ ₁ . In addition, the first and second deformation parts 37 and 43 are polarized in the + z direction as described above, and the negative and positive images of the first and second signal electrodes 39 and 45 are reversed as described above. When a signal is applied, the first and second actuators 42 and 48 are sheared in the -x direction to decrease the inclination angle θ ₁ . Therefore, since the light beams incident from the lower portion of the substrate 31 through the holes 61 are reflected by the first and second reflecting mirrors 51 and 53 twice, the change in the optical path is doubled.

As described above, the predetermined angle is provided with the first and second signal electrodes and the first and second common ground electrodes spaced apart from the adjacent actuators by the first, second, and third grooves around the holes formed in the substrate. The unit pixels are composed of first and second actuators inclined by θ ₁ , and first and second reflecting mirrors extending to holes are formed on surfaces of the first and second signal electrodes. Therefore, when an image signal of the same magnitude and opposite polarity is applied to the first and second signal electrodes, the inclination angle is changed by the shear deformation of the first and second actuators. The optical path is adjusted by twice the inclination angle at which the luminous fluxes are changed by the first and second reflecting mirrors.

Therefore, since the present invention uses the shear deformation characteristics of the piezoelectric ceramic, signal electrodes are not required inside the deformable parts, and thus, it is not necessary to form a multilayer ceramic and it is easy to manufacture.

In addition, since the incident light is reflected twice by the first and second reflecting mirrors changing in the same direction, the optical path control range is increased.

Claims (4)

A substrate having M × N holes formed by staggering a plurality of support parts and a plurality of adhesive parts and having the adhesive parts removed, and having matrix-shaped wire patterns on the lower surface thereof, and being vertically polarized with the support parts and a body The first and second grooves formed at a predetermined angle on the adhesive parts and the support parts connected to the holes and the third grooves formed between the holes at right angles with the first and second grooves. First and second signals formed on side surfaces of the first and second deformed portions exposed by the first grooves so as to be connected to the first and second deformed portions, respectively, and through the holes to a part of the lower surface of the substrate. Side surfaces of the first and second deformation portions exposed by the second grooves to be connected to neighboring ones through the surface of the electrode and the portion intersecting the third grooves. An actuator array comprising a plurality of first and second actuators having first and second common ground electrodes, wherein the first and second actuators form M × N unit pixels, and the first and second actuators. An optical path control device having first and second reflecting mirrors formed on surfaces of signal electrodes. The optical path control device of claim 1, wherein the support part is formed of any one of piezoelectric ceramics of BaTiO ₃ , PZT, or PLZT. The optical path control device according to claim 1, wherein the adhesive part is formed of epoxy or polymer. The optical path adjusting apparatus of claim 1, wherein a predetermined angle of the first and second grooves is greater than 45 ° and less than 60 °.