JP2012058757A - Display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve panel structure by providing a local thickness difference to a flattening film formed in an active matrix display device.SOLUTION: In a method for manufacturing a display device which has a panel structure composed of a pair of substrates 1 and 2 and an electrooptical substance 3 and in which an aggregate of thin film transistors and an aggregate of a flattening film 5 and a pixel electrode are formed on the substrate 1 and different display colors are assigned to respective pixel electrodes, a step of forming the flattening film comprises: a coating step of coating the flattening film 5 composed of a photosensitive material on one of the substrates; an exposure step of performing photosensitizing processing on the flattening film 5 in a state where the planar distribution of the exposure amount is varied; and a processing step of developing the flattening film 5 exposed to light so that the thickness of the flattening film 5 differs depending on the planar distribution of the exposure amount and thus the thickness of a part corresponding to the respective pixel electrodes of the flattening film 5 differs depending on the wavelength of the display color assigned to the respective pixel electrodes.

Description

  The present invention relates to a display device and a manufacturing method thereof. More specifically, the present invention relates to a planarization technique for forming a pixel electrode on a planarized surface by filling in unevenness of a thin film transistor and its wiring in an active matrix display device in which a pixel electrode and a switching thin film transistor are integrated.

  A conventional display device has a panel structure including a pair of substrates bonded to each other through a predetermined gap and an electro-optical material such as liquid crystal held in the gap. On one substrate, a set of thin film transistors, a flattening film covering them, and a set of pixel electrodes arranged on the flattening film are formed. On the other substrate, a counter electrode facing the set of pixel electrodes is formed.

  In the color display device, a color filter is formed on the other substrate, and display colors of three primary colors of red, blue, and green are assigned to each pixel electrode. Each pixel electrode transmits or reflects light having a wavelength of the assigned display color to project a desired color image. At that time, in order to obtain the optimum transmittance or reflectance in accordance with the wavelength of light corresponding to the assigned display color, an electro-optical material such as a liquid crystal according to the wavelength of the assigned display color for each pixel. Should be adjusted. However, the conventional color display device does not take such a countermeasure, and it is difficult to achieve a color balance among the three primary colors of red, blue and green.

  A conventional active matrix display device employs a high-performance polycrystalline silicon thin film transistor, so that a pixel array portion and a peripheral drive circuit portion are integrally integrated on the same substrate. Are known. The pixel array section is composed of pixel electrodes and thin film transistors that drive the pixel electrodes. The drive circuit section is also composed of a thin film transistor, and drives the pixel array section. Both the pixel array portion and the drive circuit portion formed on the same substrate are covered with a common planarization film. However, since the fine structure of the substrate surface is different between the pixel array portion and the drive circuit portion, it cannot always be uniformly flattened over both portions, and local variations occur in the thickness of electro-optical materials such as liquid crystals, resulting in image quality. Was hurting.

  Further, in the reflective display device, fine irregularities are formed on the surface of the planarizing film, and a light reflective pixel electrode is formed thereon. Thereby, desired light diffusibility can be imparted to the pixel electrode. However, a special process is required to form irregularities on the planarizing film, which complicates the manufacturing process.

  In order to solve the above-described problems of the conventional technology, the following measures were taken. That is, the present invention has a panel structure composed of a pair of substrates bonded to each other through a predetermined gap and an electro-optic material held in the gap. And a set of pixel electrodes disposed on the flattening film, and a counter electrode facing the set of pixel electrodes is formed on the other substrate. The planarizing film is made of a photosensitive material and is formed to have a different thickness in the one substrate by exposure processing. In one aspect, the one substrate includes a pixel array unit composed of a pixel electrode and a thin film transistor that drives the pixel electrode, and a drive circuit unit composed of a thin film transistor to drive the pixel array unit, The planarizing film is formed from the pixel array portion to the peripheral drive circuit portion, and the thickness is different between the pixel array portion and the drive circuit portion. In another aspect, the flattening film has a region having a different thickness so that unevenness is generated on the surface, and the pixel electrode is formed of a reflective film and is disposed in the region where the unevenness is generated. In another aspect, a different display color is assigned to each pixel electrode, and the flattening film has a thickness corresponding to each pixel electrode according to the wavelength of the display color assigned to each pixel electrode. Are formed differently.

  According to another aspect of the present invention, there is provided a method of manufacturing a display device having a panel structure including a pair of substrates bonded to each other through a predetermined gap and an electro-optic material held in the gap. , A flattening film covering these, and a set of pixel electrodes disposed on the flattening film, and a counter electrode facing the set of pixel electrodes is formed on the other substrate. A step of forming the planarizing film includes a coating step of coating the planarizing film made of a photosensitive material on the one substrate, and a state in which the planar distribution of the exposure amount is changed. An exposure process for performing a photosensitive treatment on the planarizing film, and a processing process for etching the surface of the exposed planarized film so that the thickness of the planarized film varies according to the planar distribution of the exposure amount. . Preferably, in the exposure step, the planarization film is irradiated with light through a mask in which the planar distribution of transmittance is changed to perform a photosensitive process. In this case, in the exposure step, a photosensitive process is performed a plurality of times using different masks for irradiating light of a predetermined energy amount. Alternatively, the exposure process uses a mask provided with a filter having a different energy amount at a predetermined portion in order to irradiate light of a different energy amount with the same mask. In this case, the exposure step can use a pattern capable of diffracting light as the filter. Alternatively, in the exposure step, a filter formed of two or more types of light shielding materials having different transmittances can be used. Preferably, the exposure step uses a mask provided with a filter having a transmittance of 1% to 50%.

  According to the present invention, in a display device using a liquid crystal or the like as an electro-optical material, the flattening film applied to the surface of the substrate on which active elements such as thin film transistors are integrated is devised so that the thickness varies within the substrate. Is formed. Thereby, in the case of a color display device, an optimal liquid crystal thickness can be obtained for each pixel of red, blue and green. Further, in the display device with a built-in drive circuit in which the pixel array and the peripheral drive circuit are integrally formed, gap unevenness in the panel can be improved over both the pixel array unit and the drive circuit unit. . Further, in a reflective display device, a desired light scattering function can be imparted to the pixel electrode functioning as the reflective film by changing the thickness of the flattened film so that the surface of the planarized film has an uneven shape. It can be realized with few processes.

  As described above, according to the present invention, by forming patterns with different amounts of transmitted light within the same exposure mask, it is possible to form photosensitive organic planarization films having different film thicknesses on the same substrate with a small number of steps. Is possible. As a result, a multi-gap panel can be formed in each of the RGB pixels, and the transmittance and color reproducibility can be improved. Further, by reducing the thickness of the organic flattening film on the peripheral drive circuit portion, gap unevenness can be improved and display quality can be improved. Furthermore, the concave and convex shape of the reflective display device and the contact hole can be created in the same process, and man-hours and costs can be reduced.

It is a typical fragmentary sectional view which shows the reference example of a display apparatus. It is sectional drawing which shows 1st embodiment of the display apparatus which concerns on this invention. It is a graph which shows the relationship between exposure time and the planarization film | membrane etching amount. It is a fragmentary sectional view which shows the reference example of a display apparatus. It is a fragmentary sectional view which shows the reference example of a display apparatus. It is a typical fragmentary sectional view which shows 2nd embodiment of the display apparatus which concerns on this invention. It is a fragmentary sectional view which shows the reference example of a display apparatus. It is a schematic diagram which shows 3rd embodiment of the display apparatus which concerns on this invention. It is a typical top view which shows an example of the mobile telephone terminal device which concerns on this invention. It is a typical perspective view which shows an example of the portable information terminal device which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, in order to clarify the background of the present invention, a general configuration of a color display device will be briefly described with reference to FIG. As shown in the figure, this display device has a panel structure in which an electro-optical material 130 made of liquid crystal or the like is held between a pair of glass substrates 100 and 135. A counter electrode 131, a polarizing layer 132, a color filter 133, and a black matrix 134 are formed on the upper glass substrate 135.

  On the other hand, the lower substrate 100 is formed with a pixel array portion and a drive circuit portion disposed around the pixel array portion. The pixel array section includes a pixel electrode 111 and a pixel thin film transistor (TFT-PXL) that performs switching driving. The TFT-PXL has a dual-gate bottom gate structure and is an N-channel type. On the other hand, the drive circuit unit is composed of a circuit thin film transistor (TFT-CKT) for driving the pixel thin film transistor TFT-PXL. In the figure, only one N-channel TFT-CKT having a single gate type and a bottom gate structure is shown. Each thin film transistor TFT-PXL, TFT-CKT has a laminated structure in which a semiconductor thin film 105, a gate electrode 101, and gate insulating films (102, 103) interposed therebetween are stacked. The semiconductor thin film 105 is made of, for example, polycrystalline silicon. The gate insulating film has a stacked structure of a gate nitride film 102 and a gate oxide film 103.

  The semiconductor thin film 105 is patterned in an island shape according to the element region of each thin film transistor. The patterned semiconductor thin film 105 includes a channel region ch located inside the end of the gate electrode 101, a low-concentration impurity region (LDD region) outside the channel region ch, and a low-concentration impurity region (LDD region). And a high-concentration impurity region (source region S and drain region D) continuing to the outside. The channel region ch of each thin film transistor is protected by a stopper film 106. The thin film transistors TFT-PXL and TFT-CKT having such a configuration are covered with an interlayer insulating film 107 and a protective film 108. A wiring electrode 109 is formed on the protective film 108. Each wiring electrode 109 is electrically connected to the source region S and the drain region D of each thin film transistor through contact holes opened in the interlayer insulating film 107 and the protective film 108. The wiring electrode 109 is covered with a planarizing film 110. On top of this, a pixel electrode 111 is patterned.

  As described above, the color display device shown in FIG. 1 includes the substrate 100 having the pixel array portion and the drive circuit portion, the color filter 133 and the counter electrode 131 with the electro-optical material 130 such as liquid crystal in between. The counter substrates 135 face each other. In this case, the pixel for controlling the transmitted light has an organic planarization film 110 formed as a passivation layer on a gate insulating film or an interlayer insulating film which is one of the elements constituting the thin film transistor, and ITO or the like is formed thereon. A pixel electrode 111 made of a transparent conductive film is formed. On the counter substrate 135 side, a color filter 133 of three primary colors of red, blue, and green, a black matrix 134, and a polarizing layer 132 and a counter electrode 131 that also serve as an overcoat layer thereon are formed. The film thickness of the liquid crystal layer sandwiched between both the substrates 100 and 135 is substantially constant within the substrate, and exhibits the maximum transmittance in a specific wavelength region determined by the film thickness and refractive index of the liquid crystal layer. In the case of the simple structure shown in FIG. 1, the specific wavelength region is set to green in order to maximize the panel transmittance. In some cases, when the color temperature during white display is emphasized, the specific wavelength region is designed to be blue. However, as a recent trend, further improvements in transmittance and color temperature have been demanded. For this purpose, it has been required to set an optimal liquid crystal film thickness suitable for each wavelength for each color of red, green, and blue. Yes. However, with the structure shown in FIG. 1, it is difficult to change the film thickness of the liquid crystal layer for each pixel without significantly increasing the number of steps.

  FIG. 2 is a schematic partial sectional view showing an example of the first embodiment of the display device according to the present invention. As shown in the figure, this display device has a panel structure composed of a pair of substrates 1 and 2 bonded to each other through a predetermined gap and an electro-optical material such as liquid crystal 3 held in the gap. The pair of upper and lower substrates 1 and 2 are joined to each other by a sealant 9 with the liquid crystal 3 interposed therebetween. On one substrate, a set 4 of thin film transistors included in the pixel array unit and the drive circuit unit, a planarizing film 5 covering these, and pixel electrodes arranged in the pixel array unit on the planarizing film 5 are provided. A set is formed. The pixel electrode is not shown. A wiring 6 is formed on the thin film transistor assembly 4, and the above-described planarizing film 5 is formed so as to cover the wiring 6. As described above, the thin film transistor set 4 is divided into a pixel array portion in which a plurality of pixels PXL are integrated and a peripheral drive circuit portion. On the other hand, a counter electrode facing the set of pixel electrodes is formed on the upper substrate 2. However, the counter electrode is omitted in the figure. As a feature, the planarizing film 5 is made of a photosensitive material, and is formed to have a different thickness in one substrate 1 by exposure processing. In this embodiment, the substrate 2 is provided with a color filter CF and a black matrix 7 in addition to the counter electrode, and these are further covered with a protective film 8. Actually, a counter electrode is formed on the surface of the protective film 8. Different display colors of red (R), green (G), and blue (B) are assigned to each pixel PXL by the color filter CF. Correspondingly, the planarizing film 5 is formed so that the thickness of the portion corresponding to each pixel PXL differs according to the wavelength of the display color assigned to each pixel.

  As described above, in the embodiment shown in FIG. 2, the photosensitive organic planarizing film 5 is processed, and the liquid crystal 3 having the maximum transmittance in the wavelength region of the display color assigned to each pixel PXL. Designed to achieve film thickness. In this case, the liquid crystal 3 employs, for example, an ECB liquid crystal used for the VA mode. For example, in the liquid crystal 3, the thickness of the planarizing film 5 on the substrate 1 side is set so that the red pixel portion is 3.7 μm, the green pixel portion is 3.5 μm, and the blue pixel portion is 2.8 μm. It is changing.

  In order to adjust the thickness of the planarizing film to be locally different, a photosensitive planarizing film material can be combined with photolithography and etching. In general, in order to manufacture a display device having a panel structure composed of a pair of substrates bonded to each other through a predetermined gap and an electro-optical material such as liquid crystal held in the gap, a thin film transistor is formed on one substrate. A set, a flattening film that covers them, and a set of pixel electrodes disposed on the flattening film are formed, and a counter electrode facing the set of pixel electrodes is formed on the other substrate. As described above, the flattening film is formed by applying a flattening film made of a photosensitive material on one substrate and flattening with a change in the planar distribution of the exposure amount. An exposure step for performing a photosensitive treatment of the film, and a processing step for etching the surface of the exposed flattened film so that the thickness of the flattened film varies according to the planar distribution of the exposure amount. Preferably, in the exposure step, the planarization film is irradiated with light through a mask in which the planar distribution of transmittance is changed to perform a photosensitive process. In this case, the exposure process can be performed multiple times using different masks to irradiate a predetermined amount of light. Alternatively, the exposure process may use a mask provided with a filter having a different energy amount at a predetermined portion in order to irradiate light of a different energy amount with the same mask. In the exposure process, a pattern capable of diffracting light (a pattern that cannot be resolved) can be used as the filter. Alternatively, in the exposure process, a filter formed of two or more kinds of light shielding materials (halftone materials) having different transmittances can be used. For example, in the exposure step, a mask provided with a halftone filter having a transmittance of 1% to 50% can be used.

  In particular, when the film thickness of the planarizing film is changed for each pixel, the film thickness control of the planarizing film may be such that half exposure is performed in each pixel and the film thickness is reduced by an etching amount corresponding to the exposure amount. Here, the relationship between the exposure amount of the planarizing film and the etching amount of the planarizing film is shown in FIG. In FIG. 3, the horizontal axis represents the exposure amount in terms of exposure time (msec), and the vertical axis represents the etching amount (μm) of the planarizing film. A mask using a diffraction pattern is used to control the exposure amount for the planarizing film. The film thickness can be controlled by exposing and developing using this mask. The graph of FIG. 3 shows the relationship between the exposure amount / planarization film etching amount when three different types of masks are used. Curve A is data when a fully opened mask is used, and the etching amount (the amount of reduction in the planarization film) increases as the exposure time increases. However, when the exposure time exceeds 500 msec, the etching amount is saturated. On the other hand, curve B is a stripe pattern in which bright portions and dark portions are alternately arranged, and a diffraction pattern having a bright portion width of 0.25 μm and a dark portion width of 0.25 μm is used as a mask. . At this time, it is possible to control the etching amount of the planarizing film almost in proportion to the exposure time. Further, curve C is the same when the stripe pattern mask is used, but the bright portion of the stripe pattern is 0.25 μm and the dark portion is 0.75 μm, which is darker than B. Therefore, although the etching amount increases as the exposure time increases, the increase rate is lower than B. Instead of the exposure control using the diffraction pattern as described above, a halftone material corresponding to a predetermined transmittance can be used. In this case, the mask may be formed with a layer whose film thickness is controlled so as to adjust the amount of transmitted light of a material (for example, MoSi) whose transmittance is known at a predetermined exposure wavelength. In this way, for example, two types of halftone materials having a transmittance of about 25% in the red pixel portion and a transmittance of about 20% in the green pixel portion and a complete light shielding material in the blue pixel portion are used. If a mask is formed with a layer, it is possible to control four types of film thicknesses (including a part to be completely removed).

  Next, prior to describing the second embodiment of the present invention, the background art will be briefly described with reference to FIG. FIG. 4 is a schematic partial cross-sectional view showing a reference example of an active matrix display device, and represents one pixel. This display device has pixels arranged in a matrix on a transparent substrate 201 made of glass or the like. One pixel is divided into an open area and a non-open area. A pixel PXL that emits light through the substrate 201 is formed in the opening region. Specifically, the pixel PXL includes a liquid crystal 217 held between transparent electrodes 210 and 219 facing each other, and is called a so-called liquid crystal cell. One electrode 210 is formed as a pixel electrode on the glass substrate 201 side, and the other electrode 219 is formed as a counter electrode on the counter substrate 220 side. The liquid crystal cell functions as a light valve that emits light incident from a backlight (not shown) disposed on the back side of the glass substrate 201 to the front side. The surface of the pixel electrode 210 is covered with an alignment film 216, and the surface of the counter electrode 219 is also covered with an alignment film 218.

  On the other hand, the thin film transistor TFT for driving the above-described liquid crystal cell is formed in the non-opening region. As shown in the figure, this thin film transistor has a bottom gate structure, and a polycrystalline semiconductor thin film 204P made of polysilicon or the like is formed on a gate electrode 202 made of metal via a gate insulating film 203O made of silicon oxide or the like. ing. The polycrystalline semiconductor thin film 204P is covered with an interlayer insulating film 207N made of silicon nitride, and a source electrode 205S and a drain electrode 205D are formed thereon. These electrodes 5S and 5D are covered with a planarizing film 209 made of an organic transparent resin film. The planarizing film 209 planarizes the surface of the glass substrate 201 and also serves as a protective film for the thin film transistor TFT. As described above, the pixel electrode 210 is formed on the planarizing film 209, and is electrically connected to the thin film transistor TFT via the drain electrode 205D. The gate insulating film 203O, the interlayer insulating film 207N, the planarization film 209, and the like described above overlap to form the first film configuration. This first film configuration includes a thin film transistor TFT in the non-opening region. In other words, the first film configuration is formed so as to wrap the thin film transistor from above and below. On the other hand, a second film configuration extending from the first film configuration is disposed in the opening region adjacent to the non-opening region. In the example shown in the drawing, the second film configuration is composed only of the planarizing film 209 and is interposed between the liquid crystal cell formed on the pixel electrode 210 and the glass substrate 201.

  In this reference example, an unnecessary film is removed from the opening region, and only the planarizing film 209 made of an organic resin is directly formed on the glass substrate 201. When an acrylic resin is used, the planarization film 209 has a refractive index of 1.4 to 1.6, which is almost the same as the transparent glass substrate 201. Therefore, unnecessary reflection due to the difference in refractive index does not occur at this interface. Thus, by removing as much as possible the layers having different refractive indexes from the opening region, multiple interference is reduced and the transmittance of the panel is improved. In addition, since the interference effect is eliminated, manufacturing variations between solids can be reduced. Further, the reflection of the panel can be reduced. At this time, since the non-opening region and the opening region can be processed by a common process, a new manufacturing process is not required.

  FIG. 5 is a schematic partial cross-sectional view showing a configuration including a drive circuit unit in addition to the pixel array unit of the display device shown in FIG. For easy understanding, portions corresponding to those of the first embodiment of the present invention shown in FIG. 2 are denoted by corresponding reference numerals. As shown in the figure, the display device is divided into a pixel array portion in which pixels PXL are formed in an integrated manner and a drive circuit portion around the pixel array portion. FIG. 4 described above is an enlarged view of one pixel PXL formed in the pixel array section. Both the drive circuit portion and the pixel array portion are formed on the insulating substrate 1 and include a set 4 of thin film transistors. The set 4 of thin film transistors is covered with an interlayer insulating film 10, and wiring 6 is patterned on the surface thereof. The wiring 6 is covered with a planarizing film 5 over the drive circuit portion and the pixel array portion. A color filter CF and a black matrix 7 are formed on the inner surface of the upper substrate 2. The upper and lower substrates 1 and 2 are bonded to each other by a sealing material 9 with the liquid crystal 3 therebetween. A gap spacer 11 is disposed in the gap between the two substrates 1 and 2. As described with reference to FIG. 4, the reflection due to interference is reduced by removing only the planarizing film 5 from the opening region of each pixel PXL of the pixel array portion and removing other films having different refractive indexes. Improvement of transmittance and color temperature. However, it is difficult to completely cover the step formed by the gate insulating film or the interlayer insulating film 10 (for example, about 0.6 μm) even though it is the planarizing film 5, and planarization is performed between the drive circuit unit and the pixel array unit. The step on the surface of the film 5 becomes large. Therefore, if the gap spacers 11 dispersed in the pixel array portion are placed on the planarizing film 5 of the drive circuit portion, there arises a problem that gap unevenness occurs in the peripheral portion of the panel.

  FIG. 6 shows an example of the second embodiment of the display device according to the present invention, and has a structure in which the problem of the reference example shown in FIG. 5 is solved. For easy understanding, portions corresponding to those in the reference example shown in FIG. As is apparent from the figure, in the drive circuit portion, the surface of the planarizing film 5 is made thinner than the pixel array portion by a certain thickness as shown by the dotted line. This prevents gap unevenness at the periphery of the panel. That is, by considering the thickness of the interlayer insulating film 10 and the like in advance in the peripheral drive circuit section and removing the corresponding thickness from the surface of the planarizing film 5 by etching, the entire substrate 1 is covered as a whole. The surface of the planarizing film 5 is made uniform. For example, by applying a planarizing film 5 made of a photosensitive organic resin on the surface of the substrate 1 and then locally exposing the peripheral drive circuit portion with a mask having a transmitted light amount of 25%, The surface of the planarizing film 5 can be removed by etching only from the upper part of the drive circuit portion.

  Next, before describing a third embodiment of the display device according to the present invention, the background art will be briefly described with reference to FIG. As shown in the figure, this display device includes a pair of front and rear substrates 301 and 302 bonded to each other through a predetermined gap, and an electro-optical material composed of a liquid crystal layer 303 and the like held in the gap, and is arranged in a matrix. The external pixels from the front side are reflected to the front side. The reflective region includes electrodes 310 and 322 formed on a pair of front and rear substrates 301 and 302, a liquid crystal layer 303 sandwiched between the electrodes 310 and 322, and a reflective layer 308 formed on the substrate 302 on the rear surface side. A so-called reflective liquid crystal display element LC is formed.

  A polarizing layer 340 and a quarter wave plate 309 are formed on the outer surface of the front substrate 301. A color filter CF including a colored layer 350 is formed on the inner surface of the substrate 301. A black matrix BM is also formed on the inner surface of the substrate 301 so as to divide the color filter CF for each pixel. On the surface of the color filter CF and the black matrix BM, a counter electrode 310 formed in common over each pixel is formed. An alignment film 307 is formed thereon. Further, a liquid crystal layer 303 having birefringence is interposed, and a rear substrate 302 is disposed below the liquid crystal layer 303. The surface of the substrate 302 is covered with an alignment film 315, and the liquid crystal layer 303 is horizontally aligned, for example, in cooperation with the alignment film 307 of the front substrate 301. A reflective layer 308 to be a pixel electrode is formed under the alignment film 315. The reflective layer 308 is made of a metal film formed on the uneven surface of the planarizing film 314 and constitutes a pixel electrode. A thin film transistor 308 is formed under the planarization film 314. The thin film transistor 308 has a bottom gate structure, and has a stacked structure in which a gate electrode 316, a gate insulating film 317, and a semiconductor thin film 318 are stacked in this order from the bottom. The semiconductor thin film 318 is made of, for example, polycrystalline silicon, and a channel region aligned with the gate electrode 316 is protected from above by a stopper 319. The bottom-gate thin film transistor 308 having such a structure is covered with an interlayer insulating film 320. A pair of contact holes are opened in the interlayer insulating film 320, and the source electrode 321 and the drain electrode 322 are electrically connected to the thin film transistor 308 through these contact holes. These electrodes 321 and 322 are formed by patterning, for example, aluminum. The reflection layer 308 described above is connected to the drain electrode 322. That is, the reflective layer 308 is electrically connected to the drain electrode 322 through the contact hole 312 formed in the planarization film 314. On the other hand, a signal voltage is supplied to the source electrode 321.

  In the reflective display device described above, random unevenness is formed on the planarizing film 314 applied to the surface of the substrate 302 to improve the visibility of reflected light. However, the conventional manufacturing method has a problem in productivity, such as using an exposure process of a two-layer organic planarization film in order to form this random uneven shape. Therefore, the present invention proposes the structure and manufacturing method shown in FIG. 8 as the third embodiment. For ease of understanding, FIG. 8 shows only the lower substrate 1 of the display device. A planarizing film 5 is formed on the substrate 1. The flattening film 5 has a reflection film unevenness 12 and a contact hole CON. In order to form the irregularities 12 and the contact holes CON, photolithography and etching techniques are employed. That is, the mask M is used to perform exposure processing of the planarizing film 5 having photosensitivity, and the film thickness is locally controlled. Specifically, in the mask M, the portion of the contact hole CON that completely removes the organic planarizing film 5 has a transmittance of 100%, and the portion that forms the irregularities 12 has a halftone material 51 and a complete light shielding layer of 20%. 52. That is, the halftone material 51 and the complete light shielding material 52 are formed on the base material 50 of the mask M. Thereby, it is possible to form the unevenness 12 and the contact hole CON at the same time. In controlling the concavo-convex shape, it is desirable to use an exposure apparatus having a long exposure wavelength such as g-line or h-line. In addition, when defocus is applied during exposure, it becomes easy to form a gentle uneven shape. Further, if the organic flattening film 5 is heated and reflowed, a more gentle uneven shape can be formed. According to this method, it is easy to create the unevenness 12 that has conventionally had several steps, and the cost can be reduced. In this description, a typical bottom gate type transistor is used. However, the present invention is not limited to this, and can be applied to other top gate type transistors, a-Si transistors, or simple matrix type liquid crystals. is there.

  FIG. 9 is a schematic plan view showing an example of a mobile phone terminal device according to the present invention. As shown in the figure, a mobile phone terminal 400 includes an operation unit that performs operations related to outgoing and incoming calls, a call unit that enables a call in response to the operation, and a display unit that can display at least information related to the operation. And has a compact structure. Specifically, the mobile phone terminal 400 includes an antenna 431 for wireless transmission / reception, a receiver (speaker) 432, and a transmitter (microphone) 433, as well as operation keys 434 such as dial keys, and a display unit 435. ing. This display part consists of a display device manufactured according to the invention. The mobile phone terminal device 400 can display phone book information such as a personal name and a phone number on the display unit 435. In some cases, the received electronic mail can be displayed on the display unit 435.

  FIG. 10 is a schematic perspective view showing a portable information terminal device according to the present invention. A personal digital assistant (PDA) 500 is a compact unit in which an operation unit 511 for inputting a command, a processing unit 510 for processing information according to the command, and a display unit S20 for displaying the processed information are integrated. It has a structure. The processing unit 510 includes basic functions as a PDA (communication unit, audio processing unit, control unit, storage unit, and the like). These functions are controlled by a control unit such as a CPU, so that a telephone function, a mail function, a personal computer function, a personal computer communication function, a personal information management function, and the like can be realized. Further, an operation unit 511 is provided, and various functions can be selected by operating the operation unit 511. The processing unit 510 generates image information according to the processing content to be executed. Display unit 520 displays the image information generated by information processing unit 510. Here, the display unit 520 is any one of a color display device, a reflective display device, and a drive circuit integrated display device prepared according to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Substrate, 3 ... Liquid crystal, 4 ... Assembly of thin film transistors, 5 ... Flattening film, 6 ... Wiring, 7 ... Black matrix, 9 ...・ Sealing material, CF ... Color filter

Claims (9)

A panel structure comprising a pair of substrates bonded to each other through a predetermined gap and an electro-optic material held in the gap;
On one substrate, a set of thin film transistors, a planarization film covering the collection of thin film transistors, and a set of pixel electrodes disposed on the planarization film are formed.
On the other substrate, a counter electrode facing the set of pixel electrodes is formed,
The planarizing film is made of a photosensitive material and is formed to have a different thickness in one substrate by exposure processing.
A method of manufacturing a display device in which different display colors are assigned to each pixel electrode,
The step of forming the planarizing film is as follows:
A coating process for coating a planarizing film made of a photosensitive material on one substrate;
An exposure process for performing a photosensitive treatment of the planarizing film with a change in the planar distribution of the exposure amount; and
The exposed flattening film is developed and processed so that the thickness of the flattening film differs according to the planar distribution of the exposure amount, so that the thickness of the portion corresponding to each pixel electrode of the flattening film is A processing step that varies depending on the wavelength of the display color assigned to each pixel electrode,
A method for manufacturing a display device.   The method of manufacturing a display device according to claim 1, wherein the exposure step performs the photosensitive process a plurality of times using different masks for irradiating light of a predetermined energy amount.   The method of manufacturing a display device according to claim 1, wherein the exposure step performs the photosensitive process by irradiating the planarizing film with light through a mask in which the planar distribution of transmittance is changed.   4. The method of manufacturing a display device according to claim 3, wherein the exposure step uses a mask provided with a filter having a different energy amount at a predetermined portion in order to irradiate light of a different energy amount with the same mask.   The manufacturing method of the display device according to claim 4, wherein the exposure step uses a pattern capable of diffracting light as a filter.   The method for manufacturing a display device according to claim 4, wherein the exposure step uses a filter formed of two or more kinds of light-shielding substances having different transmittances.   5. The method of manufacturing a display device according to claim 4, wherein the exposure step uses a mask provided with a filter having a transmittance of 1% to 50%. A panel structure comprising a pair of substrates bonded to each other through a predetermined gap and an electro-optic material held in the gap;
On one substrate, a set of thin film transistors, a planarization film covering the collection of thin film transistors, and a set of pixel electrodes disposed on the planarization film are formed.
On the other substrate, a counter electrode facing the set of pixel electrodes is formed,
The planarizing film is made of a photosensitive material and is formed to have a different thickness in one substrate by exposure processing.
Each pixel electrode is assigned a different display color,
The thickness of the portion corresponding to each pixel electrode of the planarizing film is different depending on the wavelength of the display color assigned to each pixel electrode. A panel structure comprising a pair of substrates bonded to each other through a predetermined gap and an electro-optic material held in the gap;
One substrate includes a pixel array unit and a drive circuit unit,
The pixel array unit has pixels arranged in a matrix,
Each pixel includes a pixel electrode and a pixel thin film transistor that drives the pixel electrode.
Each pixel is divided into an opening region in which a thin film transistor for pixels is formed, and a non-opening region.
The pixel thin film transistor formed in the non-opening region is covered with an interlayer insulating film and a planarizing film,
In the opening region, the planarization film formed in the non-opening region extends,
The pixel electrode is formed on the planarization film,
In the drive circuit portion, a circuit thin film transistor for driving the pixel thin film transistor is formed, and the circuit thin film transistor is covered with an interlayer insulating film and a planarization film,
On the other substrate, a counter electrode facing the set of pixel electrodes is formed,
The thickness of the planarization film in the non-opening region of the pixel array part is thicker than the thickness of the planarization film in the drive circuit part,
A display device in which the thickness of the portion of the electro-optic material layer located above the non-opening region of the pixel array portion is the same as the thickness of the portion of the electro-optic material layer located above the drive circuit portion.

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