JP2006154577A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the light ray pass through a liquid crystal in relatively perpendicular direction. <P>SOLUTION: A convex lens 16 for light convergence is formed on a light incidence side of the liquid crystal LC. For example, the liquid crystal LC is arranged between a pixel substrate 10 and a counter substrate 12. Then the convex lens 16 is formed on the back side of the pixel electrode 100 where the light ray from a back light 14 is received. Consequently, the oblique light ray from the back light directs in a perpendicular direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device including a liquid crystal panel that performs display by controlling a voltage applied to a liquid crystal for each pixel.

  Conventionally, there is a liquid crystal display (LCD) as a typical flat display, which is widely used from a small screen to a large screen.

  This LCD performs display by changing the orientation of the liquid crystal by applying a voltage to each pixel (liquid crystal cell) and controlling the transmission of light for each liquid crystal cell.

  Here, in the normal case, the liquid crystal cell is formed by a parallel plate such as a pair of glass substrates, and the cell gap is usually a constant value. When the liquid crystal is driven in an ECB (electrically controlled birefringence) mode including a VA (vertical alignment) mode, incident light is a product of the liquid crystal cell gap d1 and the refractive index anisotropy Δn of the liquid crystal. The state of polarization of incident light changes depending on the value determined by ## EQU1 ## and the transmittance of the cell is determined by being absorbed by the output-side polarizing plate.

  Here, a light source such as a backlight has a component that travels in an oblique direction. When light is incident on the liquid crystal cell obliquely, the optical path length is longer than the cell gap d1. In this case, for example, in the VA mode white display, the change in the polarization state becomes larger than that calculated from the cell gap. That is, as shown in FIG. 1, in the case of normal incidence, the state of polarization is determined by Δnd1, but in the case of oblique incidence (incident angle θ), it is determined by Δnd1 / cos θ. Therefore, as shown in FIG. 2, when the cell gap d1 is set at A = Δnd1 where the transmittance is highest at normal incidence, B = Δnd1 / cos θ> Δnd1 at oblique incidence, and Δnd becomes large and becomes oblique light. On the other hand, the maximum transmittance is not achieved and the transmittance is lowered. Note that the refractive index of the liquid crystal with respect to obliquely incident light is slightly different from the refractive index with respect to normal incident light, but is the same in the above.

  Therefore, conventionally, the voltage that provides the maximum transmittance when vertical light is incident is not set to a white voltage, but is set to a smaller value. That is, as shown in FIG. 3, when only vertical incidence is considered, the transmittance is highest at Vn. When Vn is viewed obliquely, the transmittance decreases. This decrease in transmittance has wavelength dependency of light, and the blue region having the shortest wavelength has the greatest decrease. For this reason, when viewed obliquely, yellow, which is a complementary color of blue, becomes strong and the white display becomes yellowish. Therefore, in general, a white voltage is set to the voltage Vo at which the transmittance is highest when viewed obliquely to prevent the white display from appearing yellowish.

  Various configurations of the liquid crystal display device are described in Patent Document 1 and the like.

WO02 / 095834A1

  However, when the cell gap of the liquid crystal is set so as to be shifted from the point where the transmittance is maximum, the transmittance when viewed from the vertical direction is lowered. As a result, the VA mode liquid crystal becomes darker than the TN (Twisted Nematic) mode having the same aperture area, and if the backlight brightness is increased to make it brighter, power consumption increases. It was.

  The present invention is a liquid crystal display device including a liquid crystal panel that performs display by controlling a voltage applied to a liquid crystal for each pixel, and condenses light incident on the liquid crystal from the outside and converts light passing through the liquid crystal to vertical light. A convex lens is provided on the incident side of the liquid crystal panel.

  The liquid crystal panel includes a TFT formed for each pixel, a pixel electrode connected to the TFT, a counter electrode corresponding to the pixel electrode of each pixel, and a liquid crystal disposed between the pixel electrode and the counter electrode. The pixel electrode is formed on a flattening film formed on the TFT, and the flattening film has a convex or concave shape, whereby the thickness of the flattening film and the thickness of the liquid crystal It is preferable that the convex lens is formed by relatively changing.

  In addition, it is preferable to provide a concave lens that spreads the light that has passed through the liquid crystal at a wide angle on the emission side of the liquid crystal panel.

  Further, the liquid crystal panel preferably includes an emission side substrate on which an opposing electrode is formed on an emission side from which light is emitted, and the concave lens is preferably formed by changing a thickness of the emission side substrate. .

  Each pixel is preferably divided into a plurality of subpixels, and a convex lens is preferably formed for each subpixel.

In addition, the liquid crystal panel includes an emission side substrate on which an opposing electrode is formed on the emission side from which light is emitted, and the concave lens is changed to a subpixel by changing the thickness of the emission side substrate for each subpixel. It is preferable to form it every time.
The liquid crystal is preferably an ECB mode liquid crystal, and particularly preferably a VA mode liquid crystal.

  As described above, according to the present invention, the convex lens that brings the light passing through the liquid crystal closer to the vertical light is provided on the incident side of the external light of the liquid crystal panel, and thus the oblique light emitted from the backlight is also vertical. It can be close to the light of the direction. Therefore, the cell gap of the liquid crystal can be brought close to the point with the maximum transmittance, and efficient display can be performed.

  Further, by forming a concave lens on the emission side from the liquid crystal, a high viewing angle can be obtained. Furthermore, an efficient convex lens can be formed by forming a convex lens using a planarizing film.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

“Embodiment 1”
FIG. 4 shows a schematic diagram of the first embodiment. The pixel substrate 10 is provided with a data line for each column in the vertical direction and a selection line for each row in the horizontal direction. Pixels partitioned by these lines are formed in a matrix, and each pixel has a selection TFT (thin film transistor) that is controlled by the signal of the selection line to input a data signal from the data line, and the acquired data. A storage capacitor for holding a signal voltage and a pixel electrode are provided.

  A counter electrode substrate 12 is disposed opposite to the pixel substrate 10 with a liquid crystal layer LC interposed therebetween. On the counter electrode substrate 12, a black matrix BM is disposed so as to surround each pixel, and a common counter electrode is formed opposite to all the pixel electrodes.

  On the other hand, a backlight 14 is disposed on the back side of the pixel substrate 10. The backlight 14 is composed of, for example, an LED (Light Emitting Diode), and irradiates the backlight toward the pixel substrate 10. Although not shown in FIG. 4, a polarizing plate, a retardation plate, and the like are bonded to the back surface side of the pixel substrate 10 and the upper surface side of the counter electrode substrate 12. Even in this case, the convex lens 16 functions as a convex lens by making the refractive index of the adhesive lower than that of the lens portion.

  A convex lens 16 is formed for each pixel on the back surface (the surface on the backlight 14 side) of the pixel substrate 10. The pixel substrate 10 usually has TFTs formed on the front side of the glass substrate, and the glass substrate is exposed as it is on the back side. Therefore, the convex lens 16 can be formed for each pixel by performing an etching process or the like on the back surface of the glass substrate. Moreover, the convex lens 16 can also be comprised by performing a sandblasting process etc. about glass, Furthermore, you may form the resin-made convex lens 16 directly on a glass substrate, or adhere | attach with an adhesive agent.

  As described above, by providing the convex lens on the backlight 14 side of the pixel substrate 10, light emitted from the backlight 14 at a wide angle can be directed in a direction perpendicular to the pixel substrate 10 as illustrated. Can reduce the probability of passing through the liquid crystal in an oblique direction. That is, as shown in FIG. 5, by providing the convex lens 16, the existence probability in the vertical direction is increased with respect to the liquid crystal incident light angle. Therefore, the cell gap can be set so that the attenuation of light in the vertical direction can be reduced, and the light use efficiency can be increased to obtain a bright screen.

“Embodiment 2”
FIG. 6 shows a schematic diagram of the second embodiment. In the second embodiment, in addition to the configuration of the first embodiment in FIG. 4, concave lenses 18 are formed on the surface of the counter electrode substrate 12 on the light emission side (opposite side of the liquid crystal layer LC) corresponding to each pixel. The counter electrode substrate 12 usually has a black matrix BM or the like formed on a glass substrate, and the glass substrate is exposed as it is on the surface. Therefore, the concave lens 18 can be formed for each pixel by performing an etching process or the like on the surface of the glass substrate. Moreover, a concave lens can also be formed by performing a sandblasting process etc. about glass, and also you may form a resin-made concave lens by adhere | attaching on a glass substrate with an adhesive agent.

  As described above, by providing the concave lens 18 on the light emitting side surface of the counter electrode substrate 12, the light condensed by the convex lens 16 is spread as shown in the figure, and the wide viewing angle of the liquid crystal display device can be achieved. .

“Embodiment 3”
FIG. 7 shows a schematic diagram of the third embodiment. In the third embodiment, the lens is formed by changing the thickness of the planarizing film.

  As shown in the figure, the pixel substrate 10 has a glass substrate 30, and a semiconductor layer 32 is formed on a required portion thereon. A gate insulating film 34 is formed so as to cover the semiconductor layer 32 and the glass substrate 30.

  A part of the semiconductor layer 32 (semiconductor layer 32-1) forms a selection TFT Q1, and a central portion is a channel region and left and right regions are a drain region and a source region, respectively. A gate electrode 36 is formed on the channel region via a gate insulating film 34. As will be described later, the gate electrode 36 is formed as a part of the gate line GL.

  Further, another part 32-2 of the semiconductor layer 32 forms a storage capacitor C, and a capacitor electrode 38 is formed on the semiconductor layer 32-2 in that part via a gate insulating film 34. A storage capacitor C is formed by the semiconductor layer 32-2, the capacitor electrode 38, and the gate insulating film 34 sandwiched therebetween. As will be described later, the capacitor electrode 38 is formed as a part of the capacitor line SCL.

  Further, an interlayer insulating film 40 is formed so as to cover the gate electrode 36, the capacitor electrode 38 and the gate insulating film 34, and a portion of the source region of the interlayer insulating film 40 and the gate insulating film 34 is removed. Is formed.

  A planarizing film 44 is formed on the front surface except for the contact hole above the source electrode 42, and a pixel electrode 46 made of a transparent conductive material (for example, IZO, ITO) is formed on the upper surface.

  A counter electrode substrate 12 is disposed opposite to the pixel substrate 10 via a liquid crystal layer LC. The counter electrode substrate 12 includes a glass substrate 48 and a counter electrode 50 formed on the liquid crystal layer LC side. Yes. Note that the black matrix BM is appropriately formed.

  Although not shown, an alignment film for controlling the alignment of the liquid crystal is provided on the surface of the pixel electrode 46 and the counter electrode 50 on the liquid crystal LC side.

  Although not shown, a data line for supplying a data signal is connected to the drain region of the selection TFT Q1. Further, the semiconductor layer 32-2 forming the storage capacitor C is electrically connected to the source region, and the capacitor electrode 38 is maintained at a predetermined low potential. Further, the counter electrode 50 is also maintained at a predetermined counter electrode potential.

  Therefore, by turning on the selection TFT Q1, the data signal of the data line can be held in the holding capacitor C, and the held voltage can be applied to the pixel electrode 46, whereby the pixel electrode 46 and the counter electrode 50 are connected. A voltage corresponding to the data signal is applied to the liquid crystal LC and display is performed.

The planarizing film 44 below the pixel electrode 46 is recessed in a concave shape. As a result, the central portion of the pixel electrode 46 is far from the counter electrode 50 and the peripheral portion is close. On the other hand, in this embodiment, when the refractive index N _LC of the liquid crystal LC and the refractive index N _PLN of the planarizing film 44 are compared, there is a relationship of N _LC > N _PLN . Accordingly, when the light from the backlight 14 is viewed, the planarizing film 44 functions as a convex lens, and as shown in the drawing, the light incident in the oblique direction is condensed and directed in the vertical direction.

In this way, when the refractive index N _LC of the liquid crystal LC and the refractive index N _PLN of the planarizing film 44 have a relationship of N _LC > N _PLN , by forming a recess in the planarizing film 44, Light incident on the liquid crystal in an oblique direction can be corrected in the vertical direction. In addition, by processing the planarization film used in the TFT process in this manner to produce a lens shape, it is possible to produce a lens corresponding to each pixel without being displaced.

  There are various types of liquid crystal materials, and the refractive index varies depending on the material. For this reason, an appropriate refractive index can be set by selecting a liquid crystal material. On the other hand, an acrylic material is usually used for the planarizing film 44, but this refractive index can also be adjusted.

“Embodiment 4”
FIG. 8 shows a schematic diagram of the fourth embodiment. In the fourth embodiment, in addition to the configuration of the third embodiment shown in FIG. 7, the convex lens layer 52 is provided on the surface of the liquid crystal layer LC of the counter electrode substrate 12 (between the counter electrode 50 and the glass substrate 48) corresponding to each pixel. Forming. The convex lens layer 52 basically has a shape corresponding to the planarizing film 44 and is preferably formed of the same material as the planarizing film 44. As a result, as shown in the figure, the oblique light from the backlight 14 is corrected in a direction perpendicular to the glass substrates 30 and 48 in the liquid crystal layer LC, and is then corrected in the oblique direction again, so that a wide viewing angle is obtained. Is displayed.

`` Plane configuration ''
FIG. 9 shows a schematic plan configuration of the third and fourth embodiments. The data line DL extends in the vertical direction for each column of pixels. On the other hand, the gate line GL extends in the horizontal direction for each row of pixels. One end of the semiconductor layer 32 is connected to the data line DL, then bends in a U shape, and passes twice under the gate line GL (thickness direction). The overlapping gate line GL forms a gate electrode 36, and the semiconductor layer 32 below the gate electrode 36 forms a channel region. A source electrode 42 is formed on the other end of the semiconductor layer 32 and is connected to the pixel electrode 46. Although not shown, the source electrode 42 and the semiconductor layer 32-2 of the storage capacitor C are connected to each other through a contact and metal, or directly through a semiconductor film. In addition, the capacitor electrode 38 is formed as a part of the capacitor line SCL extending in the row direction like the gate line GL.

  In the figure, the pixel electrode 46 (and the counter electrode 50) is formed so as to swell downward as indicated by contour lines with wavy lines.

“Embodiment 5”
In FIG. 10, the schematic diagram of Embodiment 5 is shown. Also in the fifth embodiment, the lens is formed by changing the thickness of the planarizing film.

Here, in the fifth embodiment, when the refractive index N _LC of the liquid crystal LC and the refractive index N _PLN of the planarizing film 44 are compared, there is a relationship of N _LC <N _PLN . Accordingly, when the light from the backlight 14 is viewed, the planarizing film 44 functions as a convex lens, and as shown in the drawing, the light incident in the oblique direction is condensed and directed in the vertical direction.

  As described above, the fifth embodiment is theoretically equivalent to the third embodiment except that the relationship between the refractive indexes of the planarization film 44 and the liquid crystal LC is opposite.

“Embodiment 6”
FIG. 11 shows a schematic diagram of the sixth embodiment. In the sixth embodiment, in addition to the configuration of the fifth embodiment shown in FIG. 10, a concave lens layer 54 is formed on the surface of the liquid crystal layer LC of the counter electrode substrate 12 (between the counter electrode 50 and the glass substrate 48) corresponding to each pixel. is doing. The concave lens layer 54 has a shape basically corresponding to the planarizing film 44 and is preferably formed of the same material as that of the planarizing film 44. As a result, as shown in the figure, the oblique light from the backlight 14 is corrected in a direction perpendicular to the glass substrates 30 and 48 in the liquid crystal layer LC, and is then corrected in the oblique direction again, so that a wide viewing angle is obtained. Is displayed.

“Embodiment 7”
FIG. 12 shows a schematic diagram of the seventh embodiment. In this Embodiment 7, compared with Embodiment 5, the magnitude | size of a recessed part differs. That is, one pixel is divided into two subpixels, and a recess is formed in the planarization film 44 for each subpixel.

  FIG. 13 shows a plan view of the seventh embodiment. In this manner, the rectangular pixel is divided into substantially square subpixels, and a recess is formed for each subpixel. Therefore, it is possible to collect light for each pixel more appropriate as a lens function.

“Eighth embodiment”
FIG. 14 shows a schematic diagram of the eighth embodiment. In the eighth embodiment, as in the fourth embodiment, a recess is provided on the counter electrode substrate 12 side.

“Embodiments 9 and 10”
15 and 16 are schematic diagrams of the ninth and tenth embodiments. In Embodiment 7 and 8, when compared with the refractive index N _LC of the liquid crystal LC, and a refractive index N _PLN planarizing film 44, there was a relationship N _LC> N _PLN, in this embodiment, N _LC <N _PLN . Accordingly, when the light from the backlight 14 is viewed, the planarizing film 44 functions as a convex lens, and as shown in the drawing, the light incident in the oblique direction is condensed and directed in the vertical direction.

"Alignment protrusion and alignment direction"
FIGS. 17 and 18 correspond to Embodiments 3 and 4 of FIGS. 7 and 8, respectively, and have alignment control protrusions 60. A common plan view is shown in FIG. That is, in the VA type liquid crystal, alignment control protrusions are provided to control the alignment of the liquid crystal.

  The alignment control protrusion 60 is provided at the center of the pixel of the counter electrode substrate 12, and as shown in FIG. 19, the planar shape is elliptical, and the overall shape is a conical shape.

  Since the pixel substrate 10 side has an elliptical concave shape with the deepest central portion, when a voltage is applied, all the liquid crystal on the pixel substrate 10 side is oriented toward the concave center (liquid crystal molecules fall down). ). In FIG. 19, as indicated by an arrow pointing from the outside to the inside, the liquid crystal standing perpendicular to the surface falls down toward the inside.

  On the other hand, the alignment control protrusion 60 on the counter electrode substrate 12 side has a shape corresponding to the concave portion on the pixel substrate 10 side, and therefore falls outward as indicated by the inner arrow in FIG. Therefore, the liquid crystal on the pixel substrate 10 side and the liquid crystal on the counter electrode substrate 12 side are aligned in the same direction (liquid crystal molecules are tilted). Furthermore, the direction in which the liquid crystal falls due to the oblique electric field at the edge portion of the pixel electrode 46 of the pixel substrate 10 and the direction in which the liquid crystal falls on the TFT substrate side of the concave structure portion are the same in many parts.

  Therefore, according to the present embodiment, there is a merit that the liquid crystal molecules are tilted in the direction in which the voltage is applied, thereby improving the optical response.

  In addition, when using it as a transmissive area | region to the opening part of selection TFTQ1, it is also considered to extend a concave structure to the part. However, in the case shown in the figure, it is considered that disclination is likely to occur in the opening near the TFT Q1, and in this example, it is hidden by the black matrix BM.

  20 and 21 correspond to Embodiments 5 and 6 of FIGS. 10 and 11, respectively, and have alignment control protrusions 60. FIG.

  When the pixel substrate 10 side has an elliptical convex shape that becomes higher toward the center, as shown in FIG. 22, when a voltage is applied, all the liquid crystal on the TFT substrate side falls toward the outside of the convex shape. . Therefore, on the counter electrode substrate 12 side, the protruding structure is arranged on the capacitor line, the gate line, and the drain line. That is, the alignment control protrusion 60 that swells downward toward the periphery is provided in the peripheral portion of the pixel.

  With such a configuration, the liquid crystal in the vicinity of the pixel substrate 10 and the vicinity of the counter electrode substrate 12 is aligned in the same direction (the liquid crystal molecules are tilted), and disclination is less likely to occur.

  In this example as well, portions where disclination is likely to occur are shielded by the black matrix BM.

"Lens manufacturing method"
Here, the manufacturing method of the lens by the acrylic material in the said embodiment is demonstrated below.
(I) First, a half-exposure is simply performed on a photosensitive acrylic material, and an appropriate amount of heat treatment and curing (hardening) can be performed. This method is effective when the pixel size is relatively small, and control is considered to be very difficult when the pixel size is as large as about 50 to 100 μm.
(Ii) A lens can also be produced by dividing the acrylic material process into two steps. A concave structure will be described as an example with reference to FIG.

  First, for the pixel substrate 10, TFTs are formed on a glass substrate. FIG. 23A shows that the source electrode 42 is formed.

  Next, as shown in FIG. 23B, the first acrylic material, which is the first acrylic material, is applied, leaving only the portion where the total acrylic film thickness is increased outside the concave portion of the lens. Perform exposure, development, and bleaching (color removal). Thereafter, curing (for example, UV irradiation) is performed for heat treatment and shape fixing. The film thickness is preferably 0.5 to 5 μm, more preferably about 1.5 μm. Also, a contact for connecting the pixel electrode 46 and the source electrode 42 is formed at the same time. As a result, the first acrylic layer 44-1 is formed.

  Thereafter, as shown in FIG. 23C, a 2nd acrylic material is applied, exposure, development and bleaching for the contact portion are performed, and then the shape is determined by heat treatment and curing. As a result, a planarizing film 44 having a 2nd acrylic layer 44-2 with a recessed central portion on the surface is formed. The shape of the lens can be controlled by changing the application condition and heat treatment condition of the 2nd acrylic material. For example, if a 2ND acrylic material is applied as thick as about 3 μm, the film thickness difference between the peripheral part and the center part of the concave structure can be reduced to about 0.2 μm. Further, by increasing the heat treatment time after applying the 2nd acrylic material, the difference in film thickness at the peripheral portion of the concave structure can be reduced to about 0.2 μm. By changing these conditions, it is possible to control the film thickness difference between the central part and the peripheral part of the concave structure. The film thickness difference between the central part and the peripheral part of the concave structure is preferably 0.2 μm to 3 μm. More preferably, it is about 0.5 μm.

Further, as shown in FIG. 23D, a concave lens can be formed by patterning the transparent conductor to be the pixel electrode 46.
(Iii) As a method for manufacturing the concave structure, a method as shown in FIG. 24 can be adopted. FIG. 24A is the same as FIG. 23A, and the source electrode 42 and the like are formed. As shown in FIG. 24B, a 1st acrylic material is applied, and exposure of the contact portion and half exposure within the pixel are performed. The vicinity of the contact portion is the same as (ii) above, and the first acrylic layer 44-1 is half-exposed so that the film thickness becomes thinner toward the center as it is concentric (elliptical) in the pixel. Form as a pattern.

  As shown in FIGS. 24C and 24D, the steps after the formation of the second acrylic layer 44-2 are the same as (ii). This method is considered to have a larger process margin with respect to the application conditions of the second acrylic material than the method (ii), and is considered to be easy to manufacture.

The above (ii) and (iii) are production methods in the case of N _LC > N _PLN . On the other hand, when N _LC <N _PLN , it is necessary to make a convex shape instead of a concave shape. However, even in the case of this convex shape, it can be formed by only half exposure or by performing the acrylic process twice, as in the case of the concave shape.

  In the case of the formation step (iii), the first acrylic layer 44-1 may be formed in an elliptical shape at the center of the pixel portion. The convex layer can also be formed by forming a ring-shaped pattern in which the thickness of the elliptical portion at the center is the largest and the thickness is reduced toward the outside by half exposure. In the method (iii), the film thickness is the same as that described above.

  Further, a similar method can be adopted for the counter electrode substrate 12 side.

  Here, with respect to the acrylic material and refractive index, the final acrylic material has a function as a lens. Therefore, what is required is a refractive index difference between the liquid crystal and the 2nd acrylic material in contact with the liquid crystal across the IZO (counter electrode) and the alignment film (film formed on the counter electrode and controlling the alignment of the liquid crystal).

However, when the first acrylic material is present in the light transmitting portion as shown in FIG. 24 with a concave structure, it is preferable that N _LC > N _PLN2 ≧ N _PLN1 .

Similarly, in the case of a convex structure, there are always two kinds of acrylic materials in the transmission part, and it is preferable that N _LC <N _PLN2 ≦ N _PLN1 . This is because the function (light condensing property) as a lens is higher when N _PLN2 <N _PLN1 (a gradient index lens is formed). The refractive index of liquid crystal is generally about 1.5 (abnormal light Δn = 0.1) with respect to ordinary light. As the refractive index of the acrylic material, a material having a refractive index of about 1.4 to 1.7 can be selected. Therefore, the convex structure and the concave structure can be properly used depending on the material selection.

"Other lens configuration examples"
(1) A gradient index lens is fabricated under (inside) the planarizing film.
When set larger than N _PLN2 subsequent 2nd acrylic material the refractive index N _PLN1 the 1st acrylic material in case of manufacturing a convex lens, can be formed graded index lens. At this time, the entire film may be flattened by increasing the film thickness of the second acrylic material. At this time, as described above, it is preferable to select a material having a refractive index of N _PLN1 > N _PLN2 > N _LC (voltage application).

In addition, the angle distribution of incident light is small when a material of N _PLN1 > N _PLN2 is selected. For this reason, N _PLN2 > N _LC (voltage application) is not necessarily a necessary condition.

In the case of producing a concave lens, it is preferable that N _PLN1 <N _PLN2 <N _LC (voltage application).

(2) As shown in FIG. 25, a Fresnel lens can also be produced with a 1st acrylic material.

  As shown in FIG. 25A, the process up to forming the selection TFT Q1 is the same as in FIGS. Then, as shown in FIG. 25B, a Fresnel lens is formed by the first acrylic layer 44-1. That is, a shape like a Fresnel lens is produced with a gradient index lens by using the first acrylic layer 44-1 in the planarizing film 44. In this case, the relationship between the magnitude of the refractive index and the unevenness may be the same as in the above-described embodiment.

  Here, it is considered that the cross-sectional shape of the Fresnel lens is a shape in which the lenses are cut in equal pitches in the light traveling direction and arranged on a plane, and it is difficult to make exactly. In addition, the wavelength selectivity (focal length varies depending on the wavelength) increases as it is made strictly, so it is not necessary to make it strictly.

  Thus, when the (surface) cross-sectional shape of the 1st acrylic layer 44-1 is a Fresnel lens shape, the 2nd acrylic layer 44-2 is formed relatively thick as shown in FIG. To flatten the surface. At this time, a contact for connection to the pixel electrode 46 is formed on the source electrode 42. Next, as shown in FIG. 25D, for example, an IZO pixel electrode 46 is formed on the surface of the planarizing film 44 made of the second acrylic layer 44-2.

  Thus, in this example, the lens is formed by the first acrylic layer 44-1, but the surface is flattened by the second acrylic layer 44-2.

  In the case of positively using the liquid crystal alignment direction at the time of voltage application, it is preferable that the planarizing film 44, the pixel electrode 46, and the alignment film are convex or concave. However, particularly when a lens shape is formed only on one side (pixel substrate 10 side), it is considered that a demerit that a cell gap differs within one pixel occurs. In the case of this embodiment, when a gradient index lens is formed in each pixel, the 2nd acrylic material is thickened and used as a planarizing material, thereby eliminating the change in cell gap in the pixel. In this case, the protrusions and slits for controlling the orientation have the same shape as that of a normal one.

"Pixel circuit configuration"
FIG. 26 is a diagram illustrating a configuration of a pixel circuit. The data lines DL extend in the column (column: vertical) direction of the liquid crystal panel, and one data line DL is provided for each column. The gate line GL extends in the row (row: horizontal) direction of the liquid crystal panel, and one gate line GL is provided in one row. Further, one capacitor line SCL is provided in one row in the row direction.

  The data line DL is connected to the drain of the selection TFT Q1, which is an n-channel TFT. The source of the selection TFT Q1 is connected to the pixel electrode 46 and one electrode of the storage capacitor C. The other electrode of the storage capacitor C is connected to the capacitor line SCL. A counter electrode 50 that extends across all the pixels is provided facing the pixel electrode 46, and the liquid crystal LC is disposed between the pixel electrode 46 and the counter electrode 50.

  The plurality of gate lines GL are sequentially selected by one horizontal period and set to the H level. Therefore, the selection TFT Q1 in the corresponding row whose gate is connected to the gate line GL is turned on. On the other hand, the data voltage for the pixel in the row in which the selection TFT Q1 is turned on is supplied to the data line DL. Accordingly, the storage capacitor C of each pixel in the selected row is charged with the data voltage of that pixel. As a result, the data voltage charged in the storage capacitor C is applied to the liquid crystal LC of the pixel, and display is performed. The selection of the gate lines GL is sequentially changed, but display of one pixel is continued with the written data voltage until data writing is performed in the next frame.

It is a figure explaining normal incidence and oblique incidence. It is a figure which shows the relationship between the voltage application to a liquid crystal, and the transmittance | permeability. It is a figure which shows the relationship between the voltage application and transmittance | permeability to a liquid crystal in normal incidence and diagonal incidence. 1 is a diagram illustrating a configuration of a first embodiment. It is a figure explaining the incident angle distribution of Embodiment 1. FIG. 6 is a diagram illustrating a configuration of a second embodiment. FIG. FIG. 6 is a diagram illustrating a configuration of a third embodiment. FIG. 6 is a diagram illustrating a configuration of a fourth embodiment. It is a figure which shows the planar structure of Embodiment 3,4. FIG. 10 is a diagram illustrating a configuration of a fifth embodiment. FIG. 10 is a diagram illustrating a configuration of a sixth embodiment. FIG. 10 is a diagram illustrating a configuration of a seventh embodiment. FIG. 10 is a diagram illustrating a planar configuration of a seventh embodiment. FIG. 10 is a diagram illustrating a configuration of an eighth embodiment. FIG. 10 is a diagram illustrating a configuration of a ninth embodiment. FIG. 10 is a diagram illustrating a configuration of a tenth embodiment. FIG. 6 is a diagram illustrating the alignment of liquid crystal according to a third embodiment. FIG. 6 is a diagram illustrating the alignment of liquid crystal according to a fourth embodiment. 6 is a plan view illustrating alignment of liquid crystals according to Embodiments 3 and 4. FIG. FIG. 10 is a diagram illustrating the alignment of liquid crystal according to a fifth embodiment. FIG. 10 is a diagram illustrating the alignment of liquid crystal according to a sixth embodiment. 6 is a plan view for explaining alignment of liquid crystals in Embodiments 5 and 3. FIG. It is a figure explaining an example of the lens formation method by a planarization film | membrane. It is a figure explaining the other example of the lens formation method by a planarization film | membrane. It is a figure explaining the further another example of the lens formation method by a planarization film | membrane. It is a figure which shows the structure of a pixel circuit.

Explanation of symbols

  10 pixel substrate, 12 counter electrode substrate, 14 backlight, 16 convex lens, 18 concave lens, 30, 48 glass substrate, 32 semiconductor layer, 34 gate insulating film, 36 gate electrode, 38 capacitive electrode, 40 interlayer insulating film, 42 source electrode, 44 flattening film, 46 pixel electrode, 50 counter electrode, 52 convex lens layer, 54 concave lens layer, 60 alignment control protrusion, BM black matrix, C holding capacitor, Q1 selection TFT.

Claims (7)

A liquid crystal display device including a liquid crystal panel that performs display by controlling a voltage applied to a liquid crystal for each pixel,
A liquid crystal display device comprising a convex lens on the incident side of a liquid crystal panel that collects light incident on the liquid crystal from outside and makes light passing through the liquid crystal approach vertical light. The liquid crystal display device according to claim 1.
The liquid crystal panel includes a TFT formed for each pixel, a pixel electrode connected to the TFT, a counter electrode corresponding to the pixel electrode of each pixel, a liquid crystal disposed between the pixel electrode and the counter electrode, Including
The pixel electrode is formed on a flattening film formed on the TFT. By making the flattening film convex or concave, the thickness of the flattening film and the thickness of the liquid crystal are relatively changed. Then, the convex lens is formed. The liquid crystal display device according to claim 1 or 2,
A liquid crystal display device, wherein a concave lens that spreads light that has passed through liquid crystal at a wide angle is provided on an emission side of the liquid crystal panel. The liquid crystal display device according to claim 3.
The liquid crystal panel has an emission side substrate on which a counter electrode is formed on the emission side from which light is emitted,
A liquid crystal display device, wherein the concave lens is formed by changing a thickness of the emission side substrate. The liquid crystal display device according to claim 2,
Each pixel is divided into a plurality of sub-pixels, and a convex lens is formed for each sub-pixel. The liquid crystal display device according to claim 5.
The liquid crystal panel has an emission side substrate on which a counter electrode is formed on the emission side from which light is emitted,
The concave lens is formed for each subpixel by changing the thickness of the emission side substrate for each subpixel. In the liquid crystal display device according to any one of claims 1 to 6,
A liquid crystal display device, wherein the liquid crystal is an ECB mode liquid crystal.

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