JP2002258016A - Structural body of diffusion type reflector in lcd and method of forming the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diffusion type reflector which can reflect incident light, can diffuse light at a specified solid angle with uniformity of required intensity and causes no decrease in display quality. SOLUTION: The present invention provides the method of manufacturing the structural body of a diffusion type reflector which is a substrate having a plurality of bump elements each having a reflective curved face. Each element of the plurality of bump elements has a first face and a second face, with the first angle (α or θ) between the first face and the substrate different from the second angle (β or ψ) between the second face and the substrate. The curved reflective element is manufactured by using a specially designed mask and multi-exposure shift method. The invention can be adopted for a conventional TFT-LCD eliminating a diffusing film layer as well as for the element between a liquid crystal layer and an active matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection TFT
Diffusing reflected light, such as from an LCD (thin film transistor-liquid crystal display), to a desired solid angle;
The present invention relates to a method of manufacturing a reflected light diffusing device that can deflect unpleasant high intensity reflected light beams usually formed by coated glass.

[0002]

2. Description of the Related Art To facilitate the following discussion, optical terms and variables used are first defined as indicated in FIG. The incident surface is a surface including the incident light beam and the normal direction of the reflection point. Specularly reflected light rays are defined as reflected light rays on the entrance surface whose reflection angle is equal to the angle of incidence. The light cone whose angular range is determined by the diffused light is called a diffused light cone.
The distribution angle of the diffused light cone of the plane of incidence is defined as the vertical spread angle theta _S, it is defined as the horizontal diffusion angle theta _T those perpendicular to the plane of incidence.
The deflection angle θ ₀ is the angle between the specularly reflected ray and the central ray of the diffuse light cone.

A diffusion film (for example, Polaroid Hol)
graphical Reflector and Sumit
Omo Lumisty) or bump reflectors (eg, US Pat. No. 5,610,741 and ROC Patent No. 2).
55,019) control the size of the diffused light cone, direct the reflected light distribution away from the specularly reflected light, and maintain resolution. And prevention of color dispersion cannot be achieved at the same time. However, the specularly reflected light reflected by the coated glass is undesirable in some applications,
The reason is that at the same time it is the glare of the virtual image of the light source,
This is because, depending on the viewing angle of the user, one side of a normal diffused light cone centered on the regular reflected light beam is not required. Since the efficiency of a normal reflective TFT-LCD is already as low as about 10%, extra wasted diffused light requires a more powerful light source, thus further increasing costs. There will be. Therefore, it is practically important to effectively control the diffused light and smoothly distribute the diffused light within a specific solid angle range to provide greater intensity and more complete utilization of the reflected light from the reflective liquid crystal display (LCD). Will have value.

[0004] One way to improve the above situation is by combining a diffuser film with a ramp reflector structure. Deflection of the reflected diffuse light from the specularly reflected light can be achieved in this way, but it still obviously adds to the cost of construction, lowering the resolution of the LCD and reducing the color Causes a dispersion problem.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a diffuse type reflector which can reflect incident light, can be diffused to a predetermined solid angle having a required uniformity of intensity, and does not deteriorate display quality. To provide.

Although the present invention provides a diffuse reflector that scatters incident light into a desired angular range that is deviated from specularly reflected light, one preferred embodiment of the present invention provides a reflector structure comprising a substrate and And a plurality of bump-like elements formed on the substrate according to a pattern for forming a non-planar surface. Further, the reflector includes the plurality of bump-like elements and a layer of reflective material uniformly coated on an uncoated substrate, thereby forming a non-planar reflective surface and providing an incident light from above. Reflects and diffuses light.

Each of the plurality of bump-shaped elements has a first surface and a second surface. The first surface has a slope longer than the second surface, and the normal direction of the first surface indicates a predetermined direction.

As described above, according to the present invention, each of the longer first surfaces is monotonic on the entrance surface to scatter the incident light within a desired angular range within the entrance surface with a particular intensity uniformity. It has a convex curved portion and / or a concave curved portion.

Further, as described above, according to the present invention,
Each of the longer first slopes has an irregular curvature on the entrance surface. The curvature is irregular, but the incident light is still scattered over a range of angles in the plane of incidence, however, because of the irregular surface, uniformity of intensity is not guaranteed.

Still further, in accordance with the present invention, each of the longer first slopes has a wavy bend in the horizontal plane to scatter light to a desired solid angle with a particular intensity uniformity.

Further in accordance with the present invention, each of the longer first slopes has an irregular curvature in a horizontal plane. Furthermore, despite the irregularities, the incident light is not guaranteed to be uniform in intensity, but will be scattered to a certain solid angle.

Further, the present invention provides a mask for use in an exposure process for fabricating a diffuse type reflector according to the present invention, wherein the mask includes an opaque plate having a plurality of parallel straight slits, Each of the slits may further include micropores in the form of bumps and / or patches with a recess on one side.

The present invention further provides a mask for use in an exposure process for fabricating a diffused reflector according to the present invention, wherein said mask comprises a plurality of regular wavy slits having a fixed period, or a period. Includes an opaque plate with a plurality of irregular wavy slits fixed thereto.

The present invention provides a structure of a diffusion type reflector which is a substrate having a plurality of bump-like elements having a reflection curved surface. Each of the plurality of bump-shaped elements has a first surface and a second surface, and a first angle (α or θ) between the first surface and the substrate is a second angle (α) between the second surface and the substrate. β or ψ). In the present invention, a multi-exposure shift method with a specially designed mask is proposed for the production of curved reflective elements. The diffusion film is eliminated and the conventional TFT-L as an element between the liquid crystal layer and the active matrix
The present invention can be applied to a CD.

[0015]

DETAILED DESCRIPTION OF THE INVENTION Table 1 is a comparison of the advantages of the present invention plus diffusers currently available in the industry.

[0016]

[Table 1] To maximize the use of reflected light, it would be highly desirable to be able to adjust the direction of diffused light to a normal viewing angle while maintaining resolution and avoiding color dispersion.

In view of these shortcomings and needs, the present invention proposes a new method for improving the prior ERSO slope reflector patent in a manner in which the reflective element can also diffuse the reflected light to a predetermined solid angle. First, a specially designed mask is used in the multiple exposure process for the photoresist on the substrate.
The slit bends in the mask are carefully arranged and the exposure time is fine-tuned so that the curved surface of the particular pattern is formed on the substrate after development and possibly an appropriate baking process. Then, a uniform layer of reflective material is applied on the surface thus formed. Due to the non-extinction curvature of these bump-shaped surfaces, the incident light will be reflected in a different direction from the specularly reflected light. Also, by changing the curvature in different tangential directions on the surface, the solid angle whose range is determined by the light thus diffused can be easily adjusted to the required solid angle.

In the present invention, since a specific diffusion film is not used, the structural cost is thus reduced. Not only is the resolution maintained, but the intensity of the reflected light does not decrease. Furthermore, color dispersion is not a concern in this case.
Moreover, it is possible to select a proper mask and follow the correct steps to make the reflection diffuser suitable for the application.

FIGS. 2 and 3 are microscopic schematic illustrations of the individual reflective element cross sections in a vertical plane, illustrating two ways of achieving the goal of diffusing the reflected light in the plane of incidence. . In a preferred embodiment, the entire reflector is made up of a set of such reflective elements aligned parallel to one another.

As shown in FIG. 2, the slope of the reflection surface 2 of the curved slope reflection element 1 is a monotonously convex curved portion. No two points on the slope have the same slope. The maximum and minimum slopes are at the bottom and top of the slope, respectively. The angle between the substrate and the minimum slope, in this case, the tangent at the top of the slope, is defined as θ _P , where the angle between the substrate and the maximum slope, in this case, the tangent at the bottom of the slope, is θ _V Is defined as Therefore, according to the optical principle, the reflected light will be biased from the specular reflection light by 2θ _P ~2θ _V. Therefore, with this type of reflector, the incident light is reflected and diffused into an angular range 2θ _V -2θ _P deviated by 2θ _P from the specularly reflected light. The two angles can then be adjusted along the convexity of the slope or according to the curvature of the slope, and the direction of the diffused light can be controlled to suit the actual needs.

If formed properly, that is, if it is formed with correct θ _V and θ _P and a concave surface, the same effect can be achieved even with a slope reflector having a monotonous concave slope. However, in this case, θ _V is found at the top of the slope, while θ _P is observed at the bottom. In practice, this type of structure is more difficult to obtain, because it requires an acute angle at the top of the slope.

FIG. 3 shows a reflection element 3 having an irregular slope.
Is shown. A feature of this type of structure is that the extremes of the slope of the reflecting surface 4 do not always appear at the top and bottom of the slope, and two points on the slope may have the same slope. Due to the nature of the irregular structure, the incident light will be randomly reflected in different directions, but still fall within the angular range 2? _P- 2? _V controlled by the maximum and minimum slopes. The flux density of the reflected light may not be uniform in all directions.

A preferred embodiment of the present invention is a curved reflector 5 whose structure is shown in a three-dimensional perspective view in FIG. This is characterized in that the reflecting surface 6 is curved not only in the slope direction as in the case of the curved slope reflector, but also in the horizontal direction perpendicular to the slope direction. By the same principle of reflection, an incident light ray is reflected by the curved reflector 5 as shown in FIG. 5 and scattered into a solid angle. The vertical diffusion angle θ _S , the horizontal diffusion angle θ _T , and the offset angle θ ₀ (shown in FIG. 1) are controlled by how the reflecting surface is curved and what the extremes in the different directions are. You.

FIG. 6A shows an experimental result of the curved reflector 5 in terms of the divergent ray bundles with respect to the horizontal and vertical diffusion angles. FIG.
(B) shows a schematic diagram of an ideal diffused light distribution. There, the lower circle shows the typical light incident angle, the upper circle shows the corresponding specular reflection angle, and the shaded triangular area, as shown in the wedge-shaped flux distribution in FIG. It is an object of the present invention, which is an ideal solid angle range for user observation achieved by the present invention.

In order to limit the reflected light to the expected solid angle range shown in FIG. 6, the present invention proposes a few embodiments for making curved reflectors therewith. The present invention uses a multiple exposure shift method to produce the desired reflector.
First, as shown in FIG. 7A, one positive photoresist layer 9 is formed on a substrate 10 with a predetermined thickness.
Next, according to the structure of the target reflector in the preferred embodiment of the present invention, a mask 11a having a set of parallel slits 12 having an appropriate width and a predetermined separation is shown in FIG.
It is manufactured as shown in FIG. 7 (c), (d),
As shown in (e), the photoresist layer 9 is masked with the mask 11.
a, and if necessary, exposure to a light source for a predetermined period of time, and then a mask 1 with a pitch of about one slit width.
1a is shifted and exposed again. In FIG. 7C, the photoresist layer 9 has a power of 30 m for a first predetermined period.
It is exposed to the light of J, and then the mask 11a is advanced by one pitch. Referring to FIG. 7D, the photoresist layer 9 is exposed to light having a power of 60 mJ for a second predetermined period, and thereafter, the mask 11a is advanced by one pitch. As shown in FIG. 7E, the photoresist layer 9 is exposed to light having a power of 70 mJ for a first predetermined period. If necessary, such a process is repeated several times, followed by exposing the photoresist layer 9 to a light source using a mask including a plurality of solid circles having different diameters in preparation for a final exposure step. Turn to development processing. The photoresist layer 9 in the preferred embodiment of the present invention has a positive
Can be made with photoresist. Mask 1 for final exposure
When using 1b, the portions on the photoresist layer 9 which are shaded in the hatched areas shown in FIG. 8A become convex portions after the development processing. Similarly, when the mask 11c is used in the final exposure step, FIG.
The photoresist layer 9 which is not shaded in the shaded area shown in FIG.
Each upper part becomes a concave part after the development processing. In one preferred embodiment of the present invention, an exposure treatment of the photoresist layer 9 with a mask 11b is used to show how the reflector of the LCD according to the present invention is made. FIG.
(A) shows the cross section of the photoresist layer 9 after the development process, where the slope portion 13a is formed using a mask 11a (shown in FIG. 7 (c)) and the knob portion 13b
Is formed using a mask 11b (shown in FIG. 8A). The photoresist pattern obtained after the developing process includes a plurality of knob-on-slope structures 13 parallel to each other as shown in FIG. 9A. In the figure, the knob-on-slope structure 13 has a slope portion 13a and a knob portion 13b. included. Next, the developed photoresist layer 9 is baked, and FIG. 9B shows the baked on-slope knob structure 13. FIG. 9B
FIG. 9 (c) shows a plan view of FIG. 9 (c). In the figure, the on-slope knob structures 13 can be connected one by one or separated one by one.

In a preferred embodiment of the present invention, the photoresist pattern is shown in the figure as comprising a plurality of on-slope knob structures 13 connected one at a time. A perspective view of the developed photoresist layer 9 is shown in FIG. 9 (d), in which a plurality of on-slope knob structures 13 parallel to the developed photoresist layer 9 and connected one by one are shown. included. As shown in FIG. 9D, the knob structure 13 on the slope is used.
Is formed on the substrate 10, the slope portion 13a is on the substrate 10, and the knob portion 13b is on the slope portion 13a. Using the cross section of FIG. 9D as an example, the subsequent steps for fabricating the reflector will be described. After the baking step, the reflective material 18 is formed on the upper knob structure 13 on the slope, and the cross section is shown in FIG.
(E).

The curvature in the cross section of the slope is controlled by each exposure time. Therefore, when the slit mask 11a is the same but the exposure configuration is different, a convex curved slope reflector, a concave curved slope reflector, or an irregular slope reflector can be obtained. That is, the exposure time H is a function of the photoresist thickness T, and T is also a function of the photoresist position x on the substrate 10. Therefore, in order to obtain a slope composed of a curved portion T (x), the correct light time at each point is H (T
(X)). Knob structure 13 on the slope shown in FIG.
The front end 13f and the rear end 13r of FIG.
Note that this is the only structure of the preferred embodiment using the mask 11a shown in (b). Since the parallel slit 12 is linear, both the front end 13f and the rear end 13r of the on-slope knob structure 13 are parallel straight lines.

In another preferred embodiment of the present invention, FIG.
0 can be used in the subsequent exposure steps shown in FIGS. 7 (c) to 7 (e). Then, in order to obtain an on-slope knob structure having a front end and a rear end of the curve, the mask 11b shown in FIG. 8A or the mask 11c shown in FIG. 8B is used as a mask for exposing the photoresist layer 9. use. FIG. 1 shows a cross section of a structure made by the method proposed by another preferred embodiment of the invention.
This is shown in FIG. The curved upper knob structure 22 shown in FIG. 11A has a slope portion 22a and a knob portion 22b.
Is included. The slope portion 22a is on the substrate 10, and the knob portion 22b is on the slope portion 22a. The transparent portion of the mask 20 is a curved periodic slit 24, and the front end 22f and the rear end 22r of the curved on-slope knob structure 22 are the front end 22f and the rear end 22r of the periodic curve, respectively. In addition, the first surface 22sf of the slope portion 22a intersects the substrate 10 near the front end 22f, and the second surface 22sf of the slope portion 22a.
r crosses the substrate 10 beside the front end 22r. In particular, FIG.
As shown in FIG. 1 (b), the first surface 22sf and the second surface 22s
The interface of r is a protruding top end 22m at the top of the slope portion 22a. As shown in FIG. 11B, the angles between the substrate and the first surface 22sf and the second surface 22sr are α
And β. According to the invention, the angles α and β are not identical in magnitude. In the preferred embodiment of the present invention described prior to the other preferred embodiments, the angle α shown in FIG.
Is the same as that shown in FIG. A perspective view of a curved on-slope knob structure 22 according to another preferred embodiment of the present invention is shown in FIG. After the fabrication of the curved on-slope knob structure 22 is completed, a reflective material is formed on the curved on-slope knob structure 22.

Other methods proposed by another preferred embodiment of the present invention are employed to form various types of on-slope knob structures as compared to the above two preferred embodiments of the present invention. be able to. In another preferred embodiment of the present invention, referring to FIG. 12, a mask 26 is used as a mask in an exposure process similar to that shown in FIGS.
(Including a set of transparent slits 30) is used. FIGS. 13A to 13C are plan views showing how the mask 26 moves in the exposure step of exposing the photoresist layer. Referring to FIG. 13 (a), during the exposure step, the photoresist layer is xy shown in FIG. 13 (a).
The mask 26 is arranged at a position corresponding to the coordinates and receives the first exposure. Next, a second exposure is performed on the photoresist layer by disposing a mask 26 at a position x1y1 corresponding to the xy coordinate shown in FIG. 13B. Continuing with FIG.
A third exposure is performed on the photoresist layer by disposing a mask 26 at a position x2y2 corresponding to the xy coordinates shown in (c). The above description relates to the movement of the mask during the exposure of the photoresist layer performed according to another embodiment of the present invention. Further, as in the case of the substrate, cross-sectional views showing the relevant positions of the mask 26 and the photoresist layer are shown in FIGS. Photoresist layer 32 is formed on substrate 34. Referring to FIG. 14A, the mask 26 is at a first position when the photoresist layer 32 receives the first exposure, and the power of the light source is about 30 mJ. The aforementioned first position is the same as the position of the mask 26 shown in FIG. Therefore, using a light source having a power of about 60 mJ,
Is exposed. Referring to FIG. 14B, the mask 26 is at the second position when the photoresist layer 32 is exposed for the second time. The aforementioned second position is the same as the position of the mask 26 shown in FIG. 13B, and is a position shifted from the first position by a predetermined distance in both the x-axis and the y-axis. Subsequently, the photoresist layer 32 is exposed using a light source having a power of about 70 mJ. Referring to FIG. 14C, the mask 26 is at a third position when the photoresist layer 32 is exposed for the third time. The above third position is shown in FIG.
Is the same as the position of the mask 26 shown in FIG.
This is a position shifted by a predetermined distance in both the axis and the y-axis.

After the exposing step is completed, a developing step is applied to form a photoresist pattern on the photoresist layer 32 as a step structure 38 as shown in FIG. The staircase structures 38 can be connected one by one as shown in FIG. 15 or arranged separately. Referring to FIG. 12, a set of transparent splits 30 includes a rectangular portion 30a and a protruding portion 30b, so that slots 4
0 will be formed. Next, the photoresist layer 32 is baked, and as a result, the formed step structure 3 is formed.
8 is shown in FIG. Although the desired reflector staircase structure 38 shown in FIG. 15 can be manufactured using the multi-exposure shift method described above, the same structure can be manufactured using another method that applies one-step exposure.
In the other method, the photoresist layer 3 is formed by one-step exposure.
For exposing 2, a gray level mask 45 shown in FIG. 17 is used. Due to the areas of varying transparency, the exposed photoresist layer 32 is exposed to light of various powers, resulting in a step structure 48 after the exposure and development steps. The difference between the stair structure 48 shown in FIG. 17 and the stair structure 38 shown in FIG. 15 lies in the shape of the slot 40 in FIG. Although the slot 40 in FIG. 15 is circular, the shape of the slot is partially transparent areas 50a, 50b, shown in FIG.
It can be changed according to the shapes of 50c and 50d. The transparency of the partially transparent areas arranged from low to high is 50a, 50
The order is b, 50c, and 40d. Next, the developed photoresist layer 32 is baked to smooth the end of the step structure 48. FIG. 3 shows a cross section of the baked staircase structure 48, whereas a perspective view thereof is shown in FIG.
Is shown in The following steps are for forming a reflector by forming a reflective material on the baked photoresist layer 32 and the step structure 48.

In various preferred embodiments of the present invention, the desired reflector structure is similar to the structure shown in FIG. 2 and the method is described below. According to the present invention, a bump-shaped reflector capable of reflecting incident light at a predetermined target solid angle can be manufactured.
Referring to FIG. 18, a mask 55 including a plurality of opaque areas 60 is used in the multi-exposure shift method shown in FIGS. 7 (a) to 7 (e). To illustrate the method used to form the reflector of the structure shown in FIG.
The method according to the present invention will be described using the steps described in (a) to FIG. 19 (c). As shown in FIG. 19A, a photoresist layer 64 is formed on a substrate 62, and a mask 55 having a transparent area 60 and a transparent area 60a is used as a mask for exposing the photoresist layer 64. Next, according to the present invention, the photoresist layer 64 is covered with a mask and exposed to a light source for a predetermined time as required. Subsequently, as shown in FIGS. 19A, 19B and 19C, the mask 55 is shifted by a predetermined pitch and exposed again. In FIG. 19A, the photoresist layer 64 is exposed to a light source having a power of 70 mJ for a first predetermined period,
Next, the mask 55 is moved forward by a predetermined pitch. FIG.
Referring to (d), the photoresist layer 64 is exposed again to a light source having a power of 60 mJ for a second predetermined period. Subsequently, the mask 55 is advanced by a predetermined pitch. As shown in FIG. 7C, the photoresist layer 64 is exposed to a light source having a power of 30 mJ for a predetermined period. Such processing is repeated several times as necessary, and then the photoresist layer 64 is developed. Since the photoresist layer 64 can be formed of a positive photoresist, the use of the mask 55 in the exposure process will result in the areas of the photoresist layer 64 that shadow the opaque areas 60 becoming convex after development. After the above-described multi-exposure shift and development steps, the resulting photoresist pattern is shown as bumps including portions 66a, 66b, 66c of varying heights. Due to various exposure powers of the light source used in the multi-exposure shift method, portions having various heights shown in FIG. 19C are formed. Portions 66a, 66b of the photoresist layer 64;
66c is formed from exposure to a light source of various powers. Therefore, the bump 66 shown in FIG. 20A is obtained after the developing step, and then the bump 66 is baked to smooth the end, and the structure thus formed is shown in FIG.
Are shown as baked bumps. The direction in which the mask 55 moves along the cross section of the bump 66 shown in FIG.
That is, it is captured in the direction of the line P1P2. According to a preferred embodiment of the present invention, the contact angles θ and の between the surface of the bump 66 and the substrate 62 are different. Therefore, the reflected light can be uniformly reflected and diffused to the expected solid angle. The following steps are to form a reflector according to the present invention by forming a reflective layer on a photoresist layer. The bump 66 shown in FIG.
Can be manufactured by the multi-exposure shift method described above, but it is noted that the structure shown in FIG. 20B can be manufactured using still another method without departing from the present invention. In addition, the distribution of the bumps 66 depends on the mask 55 (FIG. 1).
8) Depends on the position of the upper opaque area 60. When the areas of the opaque areas are all the same and the opaque areas 60 are evenly distributed, the resulting reflector will be the same as the reflector 5 shown in FIG. In another method used to form a bump in accordance with the present invention, a one-step exposure process may be employed to form the bump, wherein the one-step exposure process utilizes a gray level mask.
Therefore, regions of different gray levels can exhibit different clarities, thereby exposing the photoresist layer to different degrees. Accordingly, photoresist patterns of various heights are produced. The gray level mask used in the one-step exposure process is shown in FIG. 21. The gray level mask 69 has a first partially transparent area 70a, a second partially transparent area 70b, and a third partially transparent area. A plurality of transparent areas 70 including the area 70c are included. The photoresist layer 64 (FIG. 19A) was developed after being exposed using the gray level mask 69 as a mask. Since the transparency of the first partial transparent area 70a is larger than that of the second partial transparent area 70b, the transparency of the second partial transparent area 70b is
larger than that of c. The profile of the resulting photoresist layer is as shown in FIG. 20 (a), and the profile of the photoresist pattern after the baking step is shown in FIG. 20 (b). Therefore, the bumps 66 can be obtained by the other methods described above. The straight line P1P2 in FIG. 21 is the same as that in FIG. 19A, and is used to indicate the corresponding position of the bump in the photoresist pattern. There is yet another method used to form bumps according to the present invention, wherein multiple masks and light sources of various powers are used in a manner similar to that described above. Referring to FIG. 22A, a mask 72 including a plurality of opaque areas 74a.
a is used in the first exposure step, which has a power of about 3
It is used for exposing the photoresist layer 84 on the substrate 82 using a light source of 0 mJ. Next, referring to FIG. 22B, the second exposure step includes a plurality of opaque areas 74b.
Is used. In the second exposure step, a light source having a power of about 60 mJ is used to expose the photoresist layer 84 on the substrate 82. Next, referring to FIG. 22C, the photoresist layer 84 on the substrate 82 is exposed using a mask 72c including a plurality of opaque areas 74c used in the first exposure process. During the third exposure step, light used to expose the photoresist layer is emitted from a light source having a power of about 70 mJ. FIGS. 23A to 23
As shown in (c), since the area of the first partial opaque area 74a of the first mask 72a is larger than the second partial opaque area 74b of the second mask 72b, the second mask 72b
The area of the second partially opaque area 74b is the third mask 72c.
Is larger than the third partial opaque area 74c. Further, masks 72a, 72b for the exposed photoresist layer,
The corresponding positions of 72c are all the same, and additionally, masks with various opaque areas are used in combination with light sources of various powers. Therefore, the photoresist layer exposed according to the present invention has a profile as a bump 86 shown in FIG. In particular, the bump according to the present invention includes the following parts: a first part 86a, a second part 86b, and a third part 86c. Since the first portion 86a is exposed using the third mask 72c, the second portion 86b is exposed using the second mask 72b, and the third portion 86c is exposed using the first mask 72a. In addition, all masks are used in combination with various light sources of various powers. Therefore, a topography of the resulting photoresist layer is formed after the development step. Next, the cross section of the bump 86 is smoothed as shown in FIG.
The resulting photoresist pattern is baked to smooth all bump steps. Next, a reflective material is formed on the bumps 86 to manufacture a reflector according to the present invention. Although the bumps 86 are protruding, the present invention is not limited to the protruding type described above.
The bump 86 can be of a concave type as long as the transparent and opaque portions are replaced. Nevertheless, as long as the angle and the concave surface are properly shaped, the concave type will perform the same function.

FIG. 7 shows the irregular surface reflector 7. The feature of this structure is that the reflecting surface 8 does not necessarily have to be smooth or regular, and similarly it is not necessary to be limited to a convex or concave surface. The net effect of such a reflector is still to scatter the incident light to a certain solid angle, but again, the distribution need not be uniform.

It should be understood that the embodiments of the diffuse reflector described in the present invention are merely illustrative, as the size of the reflective element and the curvature pattern can be varied to suit different practical applications. is there. For example, as shown in FIG. 25, the protruding surfaces 95a of the reflectors 95, 96, 97,
96a and 97a are not the same. A crucial aspect of the present invention is the formation of a suitably curved surface in the piece of reflective material such that incident light is reflected and diffused into the preferred solid angle by the curvature of the reflective surface. Further, the distribution of the bumps in different regions of the photoresist layer can be different, as well as the shape of the bumps in different regions of the photoresist layer. For example, the profile of the bumps in the region 101 of the photoresist layer 100 can be all the same, but the profile of the bumps in the region 101 is
02, 103 or 104.

Therefore, even if all other similar structures and structures which can utilize the special reflection characteristics of the non-planar reflecting surface to diffuse the reflected light to a desired solid angle, they are regular. , Or similar to those disclosed herein with respect to irregular patterns, whether or not they fall within the scope of the invention.

Therefore, all other masks with a similar pattern, or a very different pattern that can still be employed in the manufacture of the required reflector, should be construed as part of the present invention. is there.

When the reflectors according to the invention are obtained, they can be used as reflective substrates in reflective type LCDs. An embodiment of a reflection type TFT-LCD incorporating the technology disclosed in this specification is shown in the structural cross-sectional view of FIG. Active matrix 140 is deployed on substrate 130. Then, the curved reflector 150 according to the present invention is disposed on the active matrix 140, and the reflector 150
The blank is filled with the same material as that used for the substrate. The color filter 170 is in the LC mode 160
Is interposed in the middle to cover the reflector 150. Then
The composite layer comprising the polarizer 200, the λ / 4 film 190, and the glass 180 is connected to the upper surface of the color filter 170.

A distinctive feature of the present invention is that a diffusion film is not included for the purpose of diffusing incident light. This object is achieved by utilizing a curved surface on the reflector. Thus, there is no need to worry about issues such as color dispersion, reflection efficiency, and resolution. The reflector in the specification of the present invention is a reflection type diffuser used for LCD. Because such curved surfaces of the reflectors according to the invention are properly adjusted, they also have the ability to scatter incident light to the specific solid angle required for practical applications. Therefore, these advantages are a reflection type TFT-LCD that can replace the conventional method.
In addition, manufacturing costs are greatly reduced and product performance is enhanced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating relevant optical terms and variables employed in the specification.

FIG. 2 is a schematic microscopic view showing a cross section of one reflecting element of the curved inclined reflector according to the invention in the plane of incidence.

FIG. 3 is a schematic microscopic view showing a cross section of one reflecting element of the irregularly inclined reflector according to the invention in the plane of incidence.

FIG. 4 is a three-dimensional perspective view showing the structure of a curved reflector according to the present invention.

FIG. 5 is a schematic diagram showing reflection and diffusion of an incident light ray by a curved reflector according to the present invention.

FIG. 6a is an experimental result of a light intensity distribution diffused by a curved reflector according to the present invention.

FIG. 6b is a schematic diagram showing an ideal viewing angle range.

FIG. 7a is a cross-sectional view of a substrate when a photoresist layer is formed on the substrate according to a preferred embodiment of the present invention.

FIG. 7b is a plan view of a first mask used in a multi-exposure shift method for manufacturing a diffusion type reflector (reflector) according to a preferred embodiment of the present invention.

FIG. 7c shows the position of the mask with respect to the photoresist layer,
FIG. 2 is a series of cross-sectional views illustrating steps of a multi-exposure shift method for forming a reflector on a substrate according to a preferred embodiment of the present invention.

FIG. 7d shows the position of the mask with respect to the photoresist layer,
FIG. 2 is a series of cross-sectional views illustrating steps of a multi-exposure shift method for forming a reflector on a substrate according to a preferred embodiment of the present invention.

FIG. 7e shows the position of the mask with respect to the photoresist layer,
FIG. 2 is a series of cross-sectional views illustrating steps of a multi-exposure shift method for forming a reflector on a substrate according to a preferred embodiment of the present invention.

FIG. 8a is a plan view of one type of second mask used to fabricate a knob portion of a diffuse reflector (reflector) according to a preferred embodiment of the present invention.

FIG. 8b is a plan view of another type of second mask used to fabricate the knob portion of the diffuse reflector (reflector) according to a preferred embodiment of the present invention.

9A illustrates a multi-exposure shift method using the mask illustrated in FIG. 7B and an exposure process using the mask illustrated in FIG. 8A according to a preferred embodiment of the present invention. FIG. 9 (b) shows a cross-sectional view of the knob-on-slope structure formed as a result of the application, and FIG. 9 (b) after being processed by a baking process according to a preferred embodiment of the present invention.
9C is a cross-sectional view of the knob-on-slope structure shown in FIG. 9C, and FIG. 9C is a plan view of the knob-on-slope structure shown in FIG.
FIG. 9D is a perspective view of the knob-on-slope structure shown in FIG. 9B, and FIG. 9E is a view after forming a reflective layer on the baked photoresist pattern. FIG. 3 shows a cross-sectional view of the knob-on-slope structure shown.

FIG. 10 is a plan view of a first mask used for manufacturing a slope portion of a diffusion type reflector (reflector) according to another preferred embodiment of the present invention.

FIG. 11 (a) shows a cross-sectional view of a knob on a bevel with a curved end according to another preferred embodiment of the present invention, and FIG. 11 (b) shows another preferred embodiment of the present invention. Shows a plan view of a knob-on-slope structure with a curved end,
FIG. 11 (c) shows a perspective view of the knob-on-slope structure according to another preferred embodiment of the present invention shown in FIG. 11 (b).

FIG. 12 shows a plan view of a mask used to fabricate a reflector according to another preferred embodiment of the present invention.

FIG. 13 (a) is a plan view illustrating the movement of a mask used in another preferred embodiment of the present invention, and FIG. 13 (b) is a plan view illustrating another preferred embodiment of the present invention. Fig. 1 shows a plan view explaining the movement of the mask.
FIG. 3 (c) is a plan view illustrating the movement of the mask used in another preferred embodiment of the present invention.

FIG. 14 (a) shows a series of cross-sectional views illustrating the position of the mask with respect to the photoresist layer and the steps of the multi-exposure shift method used in another preferred embodiment of the present invention. FIG. 14 (b) shows a series of cross-sectional views illustrating the position of the mask relative to the photoresist layer and the steps of the multi-exposure shift method used in another preferred embodiment of the present invention, and FIG. FIG. 4 shows a series of cross-sectional views illustrating the position of the mask relative to the layers and the steps of the multi-exposure shift method used in another preferred embodiment of the present invention.

FIG. 15 shows a cross section of a photoresist pattern of a structure formed by a method according to another preferred embodiment of the present invention, and an enlarged view of a processed staircase structure.

FIG. 16 shows an enlarged view of the staircase structure shown in FIG. 15 processed in a baking step.

FIG. 17 illustrates that another type of mask is used in the exposure process to fabricate a staircase structure according to another preferred embodiment of the present invention.

FIG. 18 shows a plan view of a mask used in the multi-exposure shift method for producing the other type of reflector shown in FIG.

19 (a) shows a cross section and a relative position of a mask and a photoresist layer during a period of manufacturing another type of reflector shown in FIG. 2, and FIG. 19 (b) shows other components shown in FIG. FIG. 19 shows a cross section and a relative position of a mask and a photoresist layer during a period of manufacturing a reflector of the type shown in FIG.
(C) shows a cross section and a relative position of the mask and the photoresist layer during a period of manufacturing another type of reflector shown in FIG.

FIG. 20A shows the result of processing by a development step, and FIG.
It is a cross-sectional view of the photoresist pattern process formed as a result of applying the method shown to (a)-(c).

FIG. 20b is a cross-sectional view of a photoresist patterning step formed as a result of applying a baking step.

FIG. 21 shows a plan view of a mask used in one exposure method for producing the other type of reflector shown in FIG.

FIG. 22a shows a plan view of a mask used in a multi-exposure method for producing the other type of reflector shown in FIG.

FIG. 22b shows a plan view of a mask used in a multi-exposure method for producing the other type of reflector shown in FIG.

FIG. 22c shows a plan view of a mask used in the multi-exposure method for producing the other type of reflector shown in FIG.

23 (a) shows a cross section of a mask and a photoresist layer used in a multi-exposure method for manufacturing the other type of reflector shown in FIG. 2, and FIG. 23 (b) shows FIG. FIG. 23 (c) shows a cross section of a mask and a photoresist layer used in a multi-exposure method for producing another type of reflector, and FIG. 2 shows a cross section of the mask and the photoresist layer that have been removed.

FIG. 24a shows the result of processing by a development step,
It is a cross-sectional view of the photoresist pattern process formed as a result of applying the method shown to (a)-(c).

FIG. 24b is a cross-sectional view of a photoresist patterning step formed as a result of applying a baking step.

FIG. 25 shows a cross section of a bump of a possible size manufactured by the process shown in FIGS. 23 (a) to 23 (c) according to the present invention.

FIG. 26 shows a possible distribution of bumps formed as a result of fabrication according to the method according to the invention.

FIG. 27 shows a TFT-LC using a diffuse type reflector (reflector) manufactured according to the method proposed by the present invention.
D shows a cross section.

[Explanation of symbols]

θ _S : Vertical diffusion angle θ _T : Horizontal diffusion angle θ ₀ : Deviation angle
θ _P : the angle between the substrate and the tangent of the smallest inclined portion θ _V : the angle between the substrate and the tangent of the largest inclined portion 1: curved slope reflection element 2: reflection surface 3: irregular slope reflection element 4: reflection Surface 5: Curved reflector 6: Reflection surface α: Angle between substrate and first surface β: Angle between substrate and second surface 9: Photoresist layer 10: Substrate 11a: Mask 11b: Mask 11c: Mask 12: Parallel slit 13: Knob structure on slope 13a: Slope portion 13
b: knob part 18: reflective material 20: mask 22:
Knob structure on slope 24: Slit 26: Mask 3
2: Photoresist layer 38: Step structure 40: Slot 55: Mask 60: Opaque area 64: Photoresist layer 66: Bump 69: Gray level mask 86: Bump 100: Photoresist layer 14
0: Active matrix 150: Reflector 160: LC
Mode 170: Color filter 180: Glass.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Xu Ji-bun, No. 378, No.13, 378 Street, 2nd Floor, Zhongxing Road, Zhudong Township, Hsinchu County, Taiwan 2H042 BA04 BA14 BA15 BA20 2H091 FA14Z LA30 2H096 AA30 EA12 GA01 HA01 HA30 JA04 2K009 AA12 CC21 DD05

Claims (5)

[The claims] 1. A structure of a diffusion type reflector, wherein the diffusion type reflector is used to scatter incident light to a predetermined angle range deviated from a regular reflection light beam, and the diffusion type reflector is: A photoresist pattern formed on a substrate,
The photoresist pattern includes a plurality of bumps, each of the plurality of bumps includes a first flat portion and a second flat portion, wherein the height of the first flat portion is higher than the height of the second flat portion. The first flat portion is adjacent to the second flat portion, each of the plurality of bumps includes a first surface and a second surface, and the first surface is the first flat portion and the second flat portion. Wherein the first surface is longer than the second surface, the first angle between the first surface and the substrate is not equal to the second angle between the second surface and the substrate, A plurality of bumps are randomly distributed on the substrate, a photoresist pattern, a reflective layer formed on the photoresist pattern, the normal direction of the first slope refers to a predetermined direction, The reflected light of the incident light reflected by the reflective layer is set in the predetermined angle range. A structure of a diffusion type reflector including a reflective layer that can be scattered. 2. A method of manufacturing a diffuse-type reflector, wherein the diffuse-type reflector is used to scatter incident light into a predetermined angle range deviated from specularly reflected light, and the method comprises the steps of: Forming a photoresist layer on the substrate, using an exposure step to expose the photoresist layer, and developing the photoresist layer to form a photoresist pattern, wherein the photoresist pattern is Including a plurality of bumps, each of the plurality of bumps includes a first flat portion and a second flat portion, wherein the height of the first flat portion is higher than the height of the second flat portion, the first flat portion A portion is adjacent to said second flat portion,
Developing the photoresist layer, and baking the developed photoresist pattern, wherein each end of the plurality of bumps of the photoresist pattern is smoothed and the plurality of baked Each of the bumps includes a first surface and a second surface, wherein the first surface is longer than the second surface, and a first angle between the first surface and the substrate is defined by the second surface and the substrate. Baking the developed photoresist pattern, wherein the plurality of bumps are not equal to the second corner between and the plurality of bumps are randomly distributed on the substrate; and forming a reflective layer on the photoresist pattern. The normal direction of the first surface points to a predetermined direction, so that the reflected light of the incident light reflected by the reflection layer can be scattered in the predetermined angle range, Method comprising the steps of forming a reflective layer on the O preparative resist pattern. 3. The step of exposing is a multi-exposure shift step, and using a first light source having a first power to expose the photoresist layer with a mask,
The mask including a plurality of transparent areas; shifting the mask by one pitch; and using a second light source having a second power to expose the photoresist layer with the mask. Wherein the first power is not equal to the second power and the first flat portion of each of the plurality of bumps is formed by exposing to the first light source; A flat portion is formed by exposing to the second light source, wherein the mask includes a plurality of transparent regions randomly distributed, and the random distribution of the plurality of bumps results from the distribution of the plurality of transparent regions on the mask. Using a second light source, formed as: 4. The exposing step wherein a light source is used to expose the photoresist layer in one exposure step under a mask covering, wherein the mask includes a plurality of transparent regions, and wherein the plurality of transparent regions Each include a first partially transparent area and a second partially transparent area, wherein the transparency of said first partially transparent area is different from the transparency of said second partially transparent area, and wherein all of said plurality of bumps have said first transparent area. A flat portion is formed by exposing the photoresist pattern to the light source through the first partially transparent area, and the second flat portion of each of the plurality of bumps is formed by exposing the light source through the second partially transparent area. 3. The method of claim 2, wherein the random distribution of the plurality of bumps is formed from the random distribution of the plurality of transparent regions on the mask. . 5. The method according to claim 1, wherein the exposing step is a multi-exposure step, and a first light source having a first power for exposing the photoresist layer by disposing a first mask at a position related to the photoresist layer. Wherein the first mask includes a first set of transparent areas, and a second power for exposing the photoresist layer by disposing a second mask at the location associated with the photoresist layer. Wherein the second mask includes a second set of transparent areas, wherein the area of the first set of transparent areas is greater than the second set of transparent areas, Each position of a set of transparent areas overlaps the second set of transparent areas, the first power is not equal to the second power, and all of the plurality of bumps have the first flatness. A portion is formed by exposing the first light source through the first mask, and all the second flat portions of the plurality of bumps are formed by exposing the second light source through the second mask. Using a second light source.