JP2009098541A - Display device, and method for manufacturing display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of effectively utilizing the light of a back light. <P>SOLUTION: A liquid crystal display device 1 comprises; an incident side glass substrate 23 which has been subjected to patterning in such a manner that a light transmission part 39a and a reflection part 39b are constituted in each of a plurality of sub-pixels 48; a light source 7; a light guide plate 9 which is disposed to face the back of the incident side glass substrate 23, and guides the light of the light source 7; a prism sheet 13 which is arranged between the incident side glass substrate 23 and the light guide plate 9, and in which a plurality of triangular prisms 13a projecting to the light guide plate 9 side and each having a slope which intersects diagonally with respect to the prescribed direction are arrayed in the prescribed direction, and transmits the light guided by the light guide plate 9 to the incident side glass substrate 23 side; and first lenses 29 and second lenses 25 arrayed between the incident side glass substrate 23 and the prism sheet 13 and functions as a condenser lens which condenses the light transmitted through the prism sheet 13 to light transmission parts 39a of the plurality of sub-pixels 48. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device such as a liquid crystal display device and a method for manufacturing the same.

  A display device that performs display by transmitting light from a backlight for each pixel, such as a so-called transmissive or transflective liquid crystal display device, is known. Each pixel of such a display device is provided with a drive circuit for controlling the luminance of each pixel or a reflection region for reflecting light from the outside of the display device. A light-transmitting region through which light is transmitted and a light-blocking region in which light from the backlight is blocked are formed. For this reason, compared with the light quantity of a backlight, the brightness | luminance of an actual pixel has fallen and the light of a backlight is not utilized effectively.

In Patent Document 1, in a transflective liquid crystal display device in which a light-transmitting region and a reflective region are formed on a pixel electrode, a microlens array is disposed between a glass substrate and a polarizing plate, so A technique is disclosed in which light is collected in a light-transmitting region and light that is originally shielded by a reflective region is transmitted through the light-transmitting region to improve the luminance of the pixel.
JP 2003-337327 A

  However, although the technique of Patent Document 1 describes that the light of the backlight is collected on the light-transmitting region of the pixel electrode by the lens, the influence of the configuration of the backlight on the light collection of the lens is mentioned. Not. For example, when the backlight is of a so-called sidelight type that guides light from a light source disposed on the side of the liquid crystal panel by a light guide plate disposed opposite to the back surface of the liquid crystal panel, The light is emitted obliquely with respect to the optical axis of the lens. The emitted light contains a lot of light that is inclined with respect to the optical axis of the lens even though it passes through the prism sheet or the diffusion plate. On the other hand, the lens is designed so as to collect light incident along the optical axis in a light-transmitting region of the pixel electrode. Therefore, the light incident obliquely on the optical axis of the lens is not condensed on the light-transmitting region of the pixel electrode, and there is a possibility that the light use efficiency of the backlight is not sufficiently improved.

  An object of the present invention is to provide a display device that can effectively use light from a backlight and a method for manufacturing the same.

  The display device of the present invention includes a transparent substrate that is patterned so that a light-transmitting region and a light-blocking region are configured in each of a plurality of pixels arranged in a predetermined direction, a back side of the transparent substrate, and the plurality of pixels A light source disposed on one side of the predetermined direction with respect to the pixel; a light guide provided to face the back surface of the transparent substrate; and guides light of the light source to the other side of the predetermined direction; and the transparent A plurality of protrusions arranged between the substrate and the light guide, projecting toward the light guide, and having slopes obliquely intersecting the predetermined direction are arranged in the predetermined direction, and the light guide A prism sheet that transmits light guided by a body to the transparent substrate side, and is arranged in the predetermined direction corresponding to the plurality of pixels between the transparent substrate and the prism sheet, and is transmitted through the prism sheet. did The focused on the translucent area of the plurality of pixels, a display device having a plurality of condensing lenses the large predetermined direction diameter than said predetermined direction of the length of the light transmission region.

  Preferably, the plurality of protrusions are provided so that two or more protrusions overlap each other in the predetermined direction with respect to each of the plurality of condenser lenses.

  Preferably, the prism sheet has a peak value of luminance of emitted light and a half value of the peak value from the light guide so as to be within a range of 20 degrees from the normal line of the prism sheet. Transmit light.

  Preferably, each of the plurality of condensing lenses has a diameter in the predetermined direction larger than a length in the predetermined direction of the translucent region, and a first lens that condenses the light transmitted through the prism sheet; And a second lens that has a shorter focal length than the first lens and emits the light emitted from the first lens to the light-transmitting region by making the light emitted from the first lens close to parallel light.

  Preferably, the first lens and the second lens are arranged so that a rear focal point of the first lens coincides with a front focal point of the second lens.

  Preferably, the plurality of second lenses are stacked on the light guide side, and the plurality of first lenses are stacked on the light guide side, more than the plurality of first lenses and the plurality of second lenses. It has a low refractive index layer with a low refractive index.

  The display device manufacturing method of the present invention performs patterning so that a plurality of pixels having a light-transmitting region and a light-blocking region are arranged in a predetermined direction on one surface of a transparent substrate, and An array step of providing a plurality of condensing lenses for condensing light from the back side on the rear surface of the one surface in the light-transmitting regions of the plurality of pixels; and after the array step, the transparent substrate A light source is provided on the back side and on one side in the predetermined direction with respect to the plurality of pixels, and a light guide that guides light of the light source in the predetermined direction is provided opposite the back surface of the transparent substrate. A prism sheet having a plurality of protrusions on one surface, the one surface facing the light guide between the transparent substrate and the light guide, and the plurality of protrusions in the predetermined direction. The slopes of the plurality of protrusions are arranged in the predetermined range Having a module step of providing to intersect the direction.

  Preferably, in the array step, a resin layer is formed on a surface of the transparent substrate on the light guide body side, and the resin layer is pressed with a mold to form a plurality of first condensing lenses. A step of forming two lenses, and a resin layer having a lower refractive index than the plurality of second lenses is formed on the plurality of second lenses, and the resin layer is pressed with a mold to form a low refractive index layer. Forming a resin layer having a higher refractive index than the low refractive index layer on the low refractive index layer and pressing the resin layer with a mold to form a plurality of condensing lenses. Forming one lens.

  Preferably, the arraying step includes a step of forming a plurality of second lenses constituting the plurality of condensing lenses on a surface of the transparent substrate on the light guide body side by photolithography, and the plurality of second lenses. A step of forming a low refractive index layer having a refractive index lower than that of the plurality of second lenses on two lenses, and a refractive index higher than that of the low refractive index layer by photolithography on the low refractive index layer; Forming a plurality of first lenses constituting the plurality of condenser lenses.

  According to the present invention, the light from the backlight can be used effectively.

  FIG. 1 is a cross-sectional view of a liquid crystal display device 1 according to an embodiment of the present invention.

  The liquid crystal display device 1 is configured by a so-called transflective liquid crystal display device, and includes a backlight 3 and a liquid crystal panel 5 that selectively transmits light from the backlight 3. The liquid crystal display device 1 includes a driver for controlling the power supplied to the liquid crystal panel 5 in addition to this, but illustration thereof is omitted.

  The backlight 3 is composed of, for example, a sidelight-type backlight, and the light source 7, a light guide plate 9 that guides light from the light source 7, and a direction other than the direction of the light source 7 toward the liquid crystal panel 5. A reflection plate 11 that reflects light toward the liquid crystal panel 5 and a prism sheet 13 for increasing luminance are provided.

  The light source 7 is composed of, for example, a cold cathode fluorescent tube, and extends in the direction penetrating the paper. The light source 7 is surrounded by a semi-cylindrical reflector 15, and the light from the light source 7 is incident on the end face of the light guide plate 9 directly or reflected by the reflector 15.

  The light guide plate 9 is formed of, for example, an acrylic plate, and is disposed so as to face the back surface of the liquid crystal panel 5 (the surface on the lower side in FIG. 1). The 1st surface 9a facing the liquid crystal panel 5 of the light-guide plate 9 is formed in the plane, for example. The second surface 9b opposite to the first surface 9a of the light guide plate 9 is formed in, for example, a saw blade shape with grooves extending in the paper surface penetrating direction of FIG. The groove portion is generally formed in a triangular shape, and when viewed from the light passing through the inside of the light guide plate 9, the inclined surface 9 c inclined toward the light source 7 is relatively long and the inclined surface 9 d inclined toward the opposite side of the light source 7 is formed. It is formed to be relatively short. The light guide plate 9 transmits the light from the light source 7 incident on the light guide plate 9 through the light guide plate 9 while reflecting the light from the first surface 9a and the second surface 9b, thereby guiding the light guide direction along the liquid crystal panel 5 (see FIG. 1).

  The reflection plate 11 is disposed to face the back surface of the light guide plate 9. In addition, the reflecting plate 11 may be comprised with appropriate materials, such as a metal. Moreover, the reflecting plate 11 may be formed of a flexible sheet. In the gap between the reflecting plate 11 and the light guide plate 9, a layer of a light transmitting material (for example, resin) may be provided.

  The prism sheet 13 is made of, for example, polyester or polycarbonate. The incident surface 13a of the prism sheet 13 facing the light guide plate 9 is formed in a saw blade shape by forming a triangular prism 13c extending in the paper surface penetration direction of FIG. The cross section of the triangular prism 13c is formed in, for example, a substantially isosceles triangle with the liquid crystal panel 5 side as a base. The length of the base is, for example, smaller than the diameter of the first lens 29 described later in the left-right direction in FIG. The plurality of triangular prisms 13c are provided so that two or more triangular prisms 13c overlap with each of the plurality of first lenses 29 in the left-right direction in FIG. The size of the apex angle of the triangular prism 13c is, for example, 80 to 100 degrees. A translucent material (for example, resin) may be disposed in the gap between the prism sheet 13 and the light guide plate 9. In this embodiment, the prism sheet 13 is conceptualized and described as a part of the backlight 3, but the prism sheet 13 may be conceptualized as a part of the liquid crystal panel 5.

  The liquid crystal panel 5 includes an array substrate 17 and a CF substrate 19 that are arranged to face each other, and a liquid crystal 21 that is sealed in a gap between the array substrate 17 and the CF substrate 19. The liquid crystal panel 5 is disposed facing the backlight 3 so that the array substrate 17 is on the backlight 3 side and the CF substrate 19 is on the opposite side of the backlight 3.

  The array substrate 17 has an incident side glass substrate 23 as a base. Various members are stacked on the incident side glass substrate 23. Specifically, on the surface of the incident side glass substrate 23 on the backlight 3 side, a second lens array 26 including a plurality of second lenses 25 and a second low refractive index layer are sequentially formed from the upper side to the lower side of the page. 27, a first lens array 30 including a plurality of first lenses 29, a first low refractive index layer 31, and an incident-side polarizing plate 33 are laminated. In addition, on the surface of the incident side glass substrate 23 on the liquid crystal 21 side, a plurality of gate electrodes (also generally referred to as Y electrodes) 35, an insulating layer 37, and a plurality of layers are sequentially arranged from the lower side to the upper side. The pixel electrode 39 and the incident-side alignment film 41 are sequentially stacked (however, some are arranged in parallel).

  In addition to this, the array substrate 17 includes data electrodes (generally also referred to as X electrodes, data signal lines, and source signal lines), TFT elements that function as switching elements for driving liquid crystals, and active matrix operation. For example, a capacitor as a signal holding capacitor is provided, but the illustration is omitted. The array substrate 17 may be provided with a protective film, an insulating film, or the like at an appropriate position.

  The pixel electrode 39 includes a light transmitting portion 39a and a reflecting portion 39b. The translucent part 39a is made of a material having translucency and conductivity, such as ITO, and can transmit light from the backlight 3 and can apply a voltage to the liquid crystal 21. The reflecting portion 39b is made of, for example, a material having reflectivity (light-shielding property) and conductivity such as aluminum, and can block light from the backlight 3 and reflect light from the liquid crystal 21 side. At the same time, a voltage can be applied to the liquid crystal 21. The light transmitting part 39a and the reflecting part 39b are electrically connected. In FIG. 1, the layer constituting the translucent part 39 a and the layer constituting the reflecting part 39 b are arranged in parallel (not stacked). For example, the translucent part has the entire width of the pixel electrode 39. The translucent portion 39a and the reflective portion 39b may be configured by laminating a reflective layer in a partial region of the optical layer. The shape, position, and size of the light transmitting portion 39a and the reflecting portion 39b may be set as appropriate. FIG. 1 illustrates a case where the light transmitting portion 39a and the reflecting portion 39b are arranged on the end side of the pixel, respectively.

  The first lens 29 and the second lens 25 are each composed of a semi-cylindrical convex lens extending in the X-axis direction (the through-plane direction in FIG. 1). Each of the first lens 29 and the second lens 25 is provided in common across the plurality of sub-pixels 48 arranged in the X-axis direction, and also arranged in the Y-axis direction (the left-right direction in FIG. 1). The same number as the plurality of pixels is provided corresponding to the pixels. The first low refractive index layer 31 and the second low refractive index layer 27 are made of a material having a refractive index lower than that of the first lens 29 and the second lens 25, respectively. The first lens 29, the second lens 25, the first low refractive index layer 31, and the second low refractive index layer 27 are made of a light-transmitting material such as glass or resin. The diameter and focus of the first lens 29 and the second lens 25 will be described later.

  The CF substrate 19 has an emission side glass substrate 43 as a base. Various members are laminated on the emission side glass substrate 43. Specifically, the exit side polarizing plate 45 is bonded to the surface of the exit side glass substrate 43 opposite to the liquid crystal 21. A black polarizing plate 47, a color filter 49, a protective film 51, a common electrode 53, and an output side alignment film 55 are stacked on the surface on the liquid crystal 21 side of the output side glass substrate 43 in order from the upper side to the lower side. (However, some are arranged in parallel.) The CF substrate 19 may be provided with a protective film, an insulating film, or the like at an appropriate position.

  The color filter 49 corresponds to a plurality of sub-pixels 48 (pixels divided into three corresponding to RGB. Sub-pixels are also a kind of pixels, and in this application, sub-pixels may be referred to as pixels). Thus, the same number of filter elements 57 as the sub-pixels 48 are provided. A plurality of types of filter elements 57 are provided corresponding to a plurality of colors (for example, RGB), and a plurality of types of filter elements 57 are arranged as a set. The sub-pixels 48 may be arranged in a so-called stripe type, may be arranged in a mosaic type, or may be arranged in a delta type.

  The basic operation of the liquid crystal display device 1 having the above configuration will be described.

  Each of the incident side polarizing plate 33 and the outgoing side polarizing plate 45 converts transmitted light into polarized light. In other words, each of the incident-side polarizing plate 33 and the outgoing-side polarizing plate 45 transmits only light that vibrates in a specific direction and blocks other light. For example, each of the incident side polarizing plate 33 and the outgoing side polarizing plate 45 converts the transmitted light into linearly polarized light.

  The liquid crystal 21 is aligned by the incident side alignment film 41 and the emission side alignment film 55. In addition, when a voltage is applied to the liquid crystal 21 via the common electrode 53 and the pixel electrode 39, the orientation of the liquid crystal 21 is different from that of the incident-side alignment film 41 and the emission-side alignment film 55 at an angle corresponding to the voltage. Oriented in the direction. The liquid crystal 21 rotates the polarized light that passes through the liquid crystal 21 at an angle corresponding to the orientation direction.

  Therefore, the amount of light of the backlight 3 transmitted through the liquid crystal panel 5 is adjusted by controlling the voltage applied to the liquid crystal 21 and controlling the angle of rotation of the polarized light traveling from the incident side polarizing plate 33 to the outgoing side polarizing plate 45. it can. Further, the angle at which the polarized light that enters the liquid crystal panel 5 from the outside of the display device (upper side of the drawing in FIG. 1) is incident on the liquid crystal panel 5 through the output side polarizing plate 45, is reflected by the reflecting portion 39b, and proceeds to the output side polarizing plate 45 is set. By controlling, the amount of reflected light can be controlled. The incident-side polarizing plate 33, the outgoing-side polarizing plate 45, the incident-side alignment film 41, and the outgoing-side alignment film 55 may be provided so as to constitute a so-called normally white liquid crystal display device. A normally black liquid crystal display device may be provided.

  The voltage applied to the liquid crystal 21 is controlled for each subpixel 48. Specifically, it is as follows. The gate electrode 35 and the data electrode (not shown) extend vertically and horizontally with respect to the array substrate 17 and form a section corresponding to the sub-pixel 48. The plurality of pixel electrodes 39 are provided in each region partitioned by the gate electrode 35 and the data electrode, and arbitrary power is selectively supplied by the gate electrode 35 and the data electrode. The pixel electrodes 39 correspond to the filter elements 57 corresponding to red, green, and blue, respectively, and the voltage applied to each pixel electrode 39 is controlled, so that the molecules of the liquid crystal 21 are subdivided for each subpixel 48. Array is controlled.

  Therefore, by controlling the balance of the amounts of light of a plurality of colors that have passed through the filter element 51, the user can visually recognize any color. Note that the common electrode 53 is provided in common to the plurality of pixel electrodes 39 and faces the plurality of pixel electrodes 39 with the liquid crystal 21 interposed therebetween. The common electrode 53 is formed of a light-transmitting and conductive material such as ITO, and transmits light from the backlight 3.

  FIG. 2 is a cross-sectional view for explaining the operation of the prism sheet 13.

  As shown in FIG. 2A, the light AL that has entered the light guide plate 9 from the light source 7 travels along the light guide plate 9 while reflecting the first surface 9 a and the second surface 9 b of the light guide plate 9. Then, the light AL is emitted from the first surface 9a, passes through the prism sheet 13, and travels to the liquid crystal panel 5 side (upper side in the drawing).

  FIG. 2B is a partially enlarged view of FIG. When the light AL is emitted from the first surface 9a, the light AL travels in a direction (a direction along the light guide plate 9) greatly inclined with respect to the normal line of the light guide plate 9. Then, the light enters the triangular prism 13c and is reflected by the inclined surface of the triangular prism 13c, thereby proceeding in a direction close to the normal line of the light guide plate 9 and the prism sheet 13, and exits from the bottom of the triangular prism 13c (the exit surface 13b of the prism sheet 13). Is done. As described above, the prism sheet 13 causes the light traveling from the light guide plate 9 in the direction inclined with respect to the normal line of the light guide plate 9 to be the normal line of the light guide plate 9 by the reflection of the inclined surface of the triangular prism 13c. Convert to light traveling in the near direction. Note that the optical path shown in FIG. 2B is a typical optical path, and in practice, the light AL is partially reflected inside the triangular prism 13c a plurality of times, etc. Go to panel 5.

  Here, a comparative example is shown in FIG. Conventionally, the prism sheet 113 (only part of which is shown) has been arranged so that the apex angle of the triangular prism 113c is on the liquid crystal panel 5 side (the upper side on the paper surface). In this case, the light AL is converted into light that enters from the bottom of the triangular prism 113c and travels in a direction closer to the normal line of the light guide plate 9 due to refraction when exiting from the inclined surface of the triangular prism 13c. Note that the optical path shown in FIG. 2C is a typical optical path. Actually, the light AL is partially reflected inside the triangular prism 13c a plurality of times, etc. Go to panel 5.

  In the arrangement of the prism sheet in FIG. 2C, since the refraction when the light AL is emitted is used, the angle correction amount of the light AL is caused by the difference between the incident angle and the refraction angle. If the angle correction amount is to be increased, a material is selected so that the difference in refractive index between the triangular prism 113c and the outside of the triangular prism 113c increases, or a complicated optical path including reflection inside the triangular prism 113c is taken into consideration. It is necessary to select the apex angle.

  On the other hand, in the prism sheet 13 of this embodiment shown in FIG. 2B, the light emitted from the light guide plate 9 can be reflected in an arbitrary direction by adjusting the angle of the inclined surface of the triangular prism 13c. Therefore, it is easy to configure so that the luminance in the normal direction of the light guide plate 9 is high. The specific shape of the triangular prism 13c needs to be set appropriately according to the alignment characteristics of the light emitted from the light guide plate 9.

  FIG. 3 is a diagram illustrating an example of the orientation characteristics of the prism sheet 13. The horizontal axis indicates the measurement angle, and the vertical axis indicates the luminance. The measurement angle indicates an angle from the normal direction of the prism sheet 13. The solid line PL1 indicates the orientation characteristic of the prism sheet 13, the solid line PL2 indicates the orientation characteristic of the prism sheet 113 shown in FIG. 2C, and the solid line PL3 indicates a case where the prism sheet is not provided (however, diffusion) The orientation characteristics are shown in which luminance unevenness is eliminated by a sheet or the like.

  As shown in this figure, when the prism sheet 13 or the prism sheet 113 is used, the luminance in the normal direction increases and the directivity increases. Here, in general, the prism sheet 113 generally used has a luminance of 1.5 to 2 times in an angle range of −30 to 30 degrees as compared with the case where the prism sheet is not used. (For example, see FIGS. 3 and 34 of “Introduction to Liquid Crystal Display Optics” (written by Yasuji Suzuki, published by Nikkan Kogyo Shimbun) and the explanation of the figure). In other words, the luminance peak value and half of the peak value are within the range of -30 to 30 degrees.

  On the other hand, the prism sheet 13 can have higher directivity than the prism sheet 113. For example, the peak value and a half value of the peak value can be set to −20 to 20 degrees, −10 to 10 degrees, or −5 to 5 degrees. Note that the solid line PL1 and the solid line PL2 in FIG. 3 were performed by the inventors under the condition that the prism sheet 13 and the prism sheet 113 are formed of the same material and in the same shape and only have different arrangement directions. The simulation results are shown, and it is also confirmed in the simulation that when the prism sheet 13 is used, the peak value and a half value of the peak value can fall within the range of -20 to 20 degrees.

  FIG. 4 is a diagram for explaining the setting and operation of the first lens 29 and the second lens 25.

  The first lens 29 has a diameter larger than the length of the translucent portion 39a in the Y-axis direction (left and right direction on the paper surface). Further, the first lens 29 is disposed so as to overlap the light transmitting portion 39a when viewed from the backlight 3 side (the lower side in the drawing). For example, the first lens 29 is disposed so that the optical axis LA1 coincides with the center of the light transmitting portion 39a. Therefore, the first lens 29 collects a light beam having a cross-sectional area wider than that of the translucent portion 39a, and originally (when the first lens 29 is not provided), the light traveling toward the periphery of the translucent portion 39a is also generated. The light can be condensed and directed toward the light transmitting portion 39a.

  The second lens 25 converts the light collected by the first lens 29 so as to approach parallel light. For example, the second lens 25 is arranged such that the optical axis LA2 coincides with the optical axis LA1 of the first lens 29, and the front focal point (focal point on the incident side of the second lens 25) FP2 is the first lens 29. The rear focal point (the focal point on the emission side of the first lens 29) is arranged so as to coincide with FP1. In the lens, the light incident on the lens parallel to the optical axis passes through the rear focal point, and the light passing through the front focal point passes through the lens and then travels parallel to the optical axis. The parallel light incident on the light 29 is collected and then converted into parallel light by the second lens 25.

  The second lens 25 is formed so that the focal length is shorter than that of the first lens 29. Therefore, as described above, when the front focal point FP2 of the second lens 25 is matched with (or close to) the rear focal point FP1 of the first lens 29, the light condensed by the first lens 29 is The cross-sectional area when incident on the second lens 25 (basically, it matches the area of the second lens 25 and may not be distinguished from the area of the second lens 25 in the following). It is smaller than 29 areas. Accordingly, the density of light emitted from the second lens is higher than the density of light incident on the first lens 29.

  And the cross-sectional area of the light radiate | emitted from the 2nd lens 25 is the same as the area of the translucent part 39a, for example. Therefore, by the combination (lens group) of the first lens 29 and the second lens 25, parallel light having a cross-sectional area larger than the area of the light transmitting portion 39a is condensed into high-density parallel light and is transmitted to the light transmitting portion 39a. It will be transmitted. As a result, a large amount of light can be transmitted through the translucent portion 39a, light is prevented from being diffused after passing through the translucent portion 39a, the front luminance is increased, and adjacent pixels are Mutual influence can be reduced.

  FIG. 5 is a flowchart for explaining the outline of the manufacturing method of the liquid crystal display device 1.

  The manufacturing method of the liquid crystal display device 1 includes an array process (S1), a cell process (S2), and a module process (S3).

  In the array step (S1), patterning or the like is performed on the incident side glass substrate 23, the gate electrode 35, the pixel electrode 39 (the light transmitting portion 39a and the reflecting portion 39b), a driving circuit (not shown), the first lens 29 and the second lens 29. A lens 25 and the like are formed. Further, patterning or the like is performed on the emission side glass substrate 43, and the color filter 49, the common electrode 53, and the like are formed.

  In the cell process (S2), the array substrate 17 and the CF substrate 19 are bonded together, and the liquid crystal 21 is sealed in the gap. In the module process (S3), the liquid crystal panel 5 and the backlight 3 are combined and fixed. The arrangement relationship between the liquid crystal panel 5 and the various members of the backlight 3 (the light source 7, the light guide 9, the prism sheet 13, etc.) is as described with reference to FIG. A driver (not shown) is connected to the liquid crystal panel 5 and the backlight 3.

  FIG. 6 is a flowchart for explaining an example of a process of forming the first lens 29 and the second lens 25 in the array process (S1). FIG. 6 illustrates a method of forming the first lens 29 and the second lens 25 by a molding method using ultraviolet (UV) transfer. Specifically, it is as follows.

  First, as shown in FIG. 6A, a resin layer 401 is formed on the incident side glass substrate 23 by applying a resin having a relatively high refractive index. The resin layer 401 is made of, for example, a photocurable resin. Next, as shown in FIG. 6B, the resin layer 401 is pressed by a mold 501 in which a recess corresponding to the shape of the second lens 25 is formed. Note that the mold 501 is formed of a light-transmitting material such as quartz. And as shown in FIG.6 (c), an ultraviolet-ray (UV) is irradiated through the type | mold 501, and the resin layer 401 is hardened. As a result, the second lens 25 is formed as shown in FIG. 6D, which shows a state where the mold is peeled off.

  Similar to the second lens 25, the second low refractive index layer 27, the first lens 29, and the first low refractive index layer 31 are also formed by forming a resin layer, pressing, ultraviolet irradiation, and mold peeling. Specifically, it is as follows.

  As shown in FIG. 6E, a resin layer 403 having a relatively low refractive index is formed on the second lens 25. Next, as shown in FIG. 6 (f), the resin layer 403 is pressed by a mold 503. And although illustration is abbreviate | omitted, the 2nd low refractive index layer 27 is formed by irradiation of an ultraviolet-ray, and peeling of the type | mold 503 is performed.

  As shown in FIG. 6G, a resin layer 405 having a relatively high refractive index is formed on the second low refractive index layer 27. Next, as shown in FIG. 6 (h), the resin layer 405 is pressed by a mold 505. And although illustration is abbreviate | omitted, the 1st lens 29 is formed by irradiation of an ultraviolet-ray, and peeling of the type | mold 505 is performed as shown in FIG.6 (i).

  Thereafter, although not shown, a low-refractive index resin layer is formed on the first lens 29, and the resin layer is pressed with a mold and irradiated with ultraviolet rays to form the first low-refractive index layer 31. Note that the molding method is not limited to using UV transfer, and may use thermal transfer.

  FIG. 7 is a flowchart for explaining another example of the step of forming the first lens 29 and the second lens 25 in the array step (S1). FIG. 7 illustrates a method of forming the first lens 29 and the second lens 25 by photolithography. Specifically, it is as follows.

  First, as shown in FIG. 7A, a resin layer 451 is formed on the incident side glass substrate 23 by applying a resin having a relatively high refractive index. The resin layer 451 is made of, for example, a photocurable resin. Next, as shown in FIG. 6B, a resist layer 453 is formed. The resist may be a negative resist or a positive resist. As shown in FIG. 7C, the resist layer 453 is formed in a predetermined pattern by exposure and development. As shown in FIG. 7D, the non-arranged region of the resist layer 453 in the resin layer 451 is cured by being irradiated with ultraviolet rays. As shown in FIG. 7E, the resist layer 453 is peeled off, and as shown in FIG. 7F, the resin layer 451 is etched to form the resin layer 451 in a predetermined pattern. The Then, when the incident side glass substrate 23 is heated by the reflow furnace, the resin layer 451 is softened and rounded, and the second lens 25 is formed.

  Next, as shown in FIG. 7H, the second low refractive index layer 27 is formed. The second low refractive index layer 27 is formed by, for example, irradiating ultraviolet rays after a photocurable resin is applied on the second lens 25.

  As with the second lens 25, the first lens 29 is formed of a resin layer 455 having a high refractive index (FIG. 7 (i)), a resist layer 457 (FIG. 7 (j)), a resist layer formed by exposure and development. Patterning of 457 (FIG. 7 (k)), curing of the resin layer 455 by ultraviolet irradiation (FIG. 7 (l)), peeling of the resist layer 457 (FIG. 7 (m)), etching of the resin layer 455 (FIG. 7 (n) )), And reflow (FIG. 7 (o)). The first low refractive index layer 31 is formed in the same process as the second low refractive index layer 27.

  According to the above embodiment, the incident side glass substrate 23 patterned so that the translucent part 39a and the reflection part 39b are configured in each of the plurality of sub-pixels 48, and the back side from the incident side glass substrate 23 In addition, the light source 7 disposed on one side in a predetermined direction (light guide direction, right and left direction in FIG. 1) from the plurality of sub-pixels 48 and the back surface of the incident side glass substrate 23 are provided to face each other. A light guide plate 9 that guides light in the light guide direction, a plurality of light guide plates 9 disposed between the incident-side glass substrate 23 and the light guide plate 9, projecting toward the light guide plate 9, and having inclined surfaces that intersect the light guide direction The triangular prisms 13c are arranged in the light guide direction, and are arranged between the prism sheet 13 that transmits the light guided by the light guide plate 9 toward the incident side glass substrate 23, and between the incident side glass substrate 23 and the prism sheet 13. And prize A plurality of condensing lenses (first lenses) that condense the light transmitted through the sheet 13 onto the light transmitting portions 39a of the plurality of sub-pixels 48 and have a diameter in the light guide direction that is longer than the length of the light transmitting portions 39a in the light guide direction. Therefore, the light emitted obliquely from the light guide plate 9 is converted into light in a direction perpendicular to the incident side glass substrate 23 by the prism sheet 13 and converted. Light can be incident on the first lens 29 and the second lens 25. Therefore, light can be efficiently collected along the optical axes of the first lens 29 and the second lens 25. In other words, it is possible to suppress the light from the light guide plate 9 from passing through the first lens 29 and the second lens 25 toward the periphery of the translucent part 39a. As described with reference to FIG. 2 and FIG. 3, the prism sheet 13 has the surface on which the irregularities are formed facing the light guide plate 9. Compared with the case where it is directed to the glass substrate 23 side, the light emitted obliquely from the light guide plate 9 can be efficiently and simply converted into a direction orthogonal to the incident side glass substrate 23.

  For example, the peak value of the luminance of the emitted light, which is not realized by the arrangement of the conventional prism sheet 113, and a half value of the peak value are within a range of 20 degrees from the normal line of the prism sheet 13, It is possible to transmit light from the light guide plate 9.

  The plurality of triangular prisms 13c are provided so that two or more triangular prisms 13c overlap each other with respect to each of the plurality of condensing lenses (the first lens 29 and the second lens 25) in a predetermined direction (left and right direction in FIG. 1). Therefore, in each sub-pixel 48, luminance unevenness due to the provision of the triangular prism 13c does not occur.

  Each of the plurality of condensing lenses that collect light on the plurality of translucent portions 39a has a diameter in the predetermined direction that is longer than the length of the translucent portion 39a in the predetermined direction (the left-right direction in FIG. 1), and is transmitted through the prism sheet 13. A first lens 29 that collects the emitted light, and a second lens 25 that has a shorter focal length than the first lens 29 and that emits the light emitted from the first lens 29 close to parallel light and emits the light to the translucent portion 39a. Therefore, as described with reference to FIG. 4, the light collected by the first lens 29 is suppressed from being diverged after passing through the translucent portion 39a, and the front luminance is improved. As a result, the degree of freedom in designing the thickness of the liquid crystal panel 5 is also improved.

  Since the first lens 29 and the second lens 25 are arranged so that the rear focal point FP1 of the first lens 29 and the front focal point FP2 of the second lens 25 coincide with each other, the second lens 25 can be accurately used. Parallel light can be formed, and the effect of improving the above-described front luminance is preferably obtained.

  The liquid crystal display device 1 is stacked on the light guide plate 9 side of the plurality of second lenses 25, and the plurality of first lenses 29 and the plurality of second lenses 25 are stacked on the light guide plate 9 side. In addition, since the second low refractive index layer 27 having a lower refractive index is provided, it is easy to form the plurality of first lenses 29 and the plurality of second lenses 25. For example, the above-described front focus and rear focus are easily matched by adjusting the film thickness of the second low refractive index layer 27.

  In the method of manufacturing the liquid crystal display device 1, a plurality of sub-pixels 48 each having a light transmitting portion 39 a and a reflecting portion 39 b with respect to one surface of the incident side glass substrate 23 (surface on the upper side in FIG. 1) are predetermined. The patterning is performed so that the light is arranged in the direction (left and right direction in FIG. 1), and a plurality of light beams from the back side are applied to the back side of the incident side glass substrate 23 (surface on the lower side in FIG. 1). An array step (S1) for providing a plurality of condensing lenses (first lens 29 and second lens 25) for condensing on the light transmitting portion 39a of the sub-pixel 48, and after the array step, behind the incident side glass substrate 23 The light source 7 is provided on the side (the lower side of the drawing in FIG. 1) and on one side of the predetermined direction (the left and right direction on the drawing in FIG. 1) from the plurality of sub-pixels 48. An optical plate 9 is provided opposite the back side of the incident side glass substrate 23 to The prism sheet 13 having a plurality of triangular prisms 13c on the surface 13c is arranged between the incident side glass substrate 23 and the light guide plate 9, the incident surface 13c faces the light guide plate 9, and the plurality of triangular prisms 13c are arranged in the predetermined direction. And a module step (S3) provided so that the slopes of the plurality of triangular prisms 13c intersect with the predetermined direction. In the conventional manufacturing method, a lens is formed in the array step, The liquid crystal display device 1 can be configured simply by adding a step of disposing the prism sheet 13 toward the opposite side.

  In the array step (S1) shown in FIG. 6, a resin layer 401 is formed on the surface on the light guide plate 9 side of the incident side glass substrate 23, and the resin layer 401 is pressed with a mold 501 to form a plurality of second lenses. And a resin layer 403 having a refractive index lower than that of the plurality of second lenses 25 is formed on the plurality of second lenses 25, and the resin is formed. The step of forming the second low refractive index layer 27 by pressing the layer 403 with the mold 503 (FIGS. 6E and 6F), and the second low refractive index layer 27 on the second low refractive index layer 27 Forming a resin layer 405 having a higher refractive index than the layer and pressing the resin layer 405 with a mold 505 to form a plurality of first lenses 29 (FIGS. 6G to 6I). Therefore, the first lens 29 and the second lens 25 can be easily formed, and the second low refractive index layer 27 is formed. The control such as the pressing force of the mold 503, conveniently may be the first lens 29 ones appropriate distance between the second lens 25.

  The array step (S1) shown in FIG. 7 is a step of forming a plurality of second lenses 25 by photolithography on the surface on the light guide plate 9 side of the incident side glass substrate 23 (FIGS. 7A to 7). g)), a step of forming a second low refractive index layer 27 having a lower refractive index than the plurality of second lenses 25 on the plurality of second lenses 25 (FIG. 7H), and a second low refraction. A step of forming a plurality of first lenses 29 having a refractive index higher than that of the second low refractive index layer 27 by photolithography on the refractive index layer 27 (FIGS. 7I to 7O). The first lens 29 and the second lens 25 can be formed similarly to the formation of the pixel electrode 39 and the like, and the manufacturing process is simplified.

  In the above embodiment, the liquid crystal display device 1 is an example of the display device of the present invention, the sub-pixel 48 is an example of the pixel of the present invention, and the light transmitting portion 39a is an example of the light transmitting region of the present invention. The reflecting portion 39b is an example of the light shielding region of the present invention, the incident side glass substrate 23 is an example of the transparent substrate of the present invention, the light guide plate 9 is an example of the light guide of the present invention, and the triangular prism 13c is It is an example of the protrusion part of the prism sheet of this invention, and the lens group which consists of the 1st lens 29 and the 2nd lens 25 is an example of the condensing lens of this invention.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The display device is not limited to a liquid crystal display device. What is necessary is just to display by transmitting the light from a light source to the translucent area | region formed in the transparent substrate. In the embodiment, a so-called transflective liquid crystal display device is shown, but a so-called transflective display device may be used. Even in an all-transmissive display device, a light-shielding region is actually formed by a gate electrode or a drive circuit, so that the light from the light source can be effectively used by condensing the light in the light-transmitting region. It is done. The driving method of the display device may be an active matrix method or a simple matrix method, and the configuration of the drive circuit or the like may be a reverse stagger method (bottom gate method) or a normal stagger method (top gate method).

  The light guide direction of the light guide (9) is not limited to the X-axis direction. For example, it may be in the Y-axis direction. The semi-cylindrical lens can be arranged to extend in the Y-axis direction if it is a stripe type or a mosaic type. Moreover, the shape of the light guide may be set as appropriate. For example, the surface opposite to the prism sheet may be formed in a flat shape.

  The arrangement position of a prism sheet should just be between a condensing lens (25 and 29) and a light guide (9), and is not limited to the backlight side of an incident side polarizing plate (33). For example, the prism sheet may be provided on the output side with respect to the incident side polarizing plate (33). In addition, the arrangement position of the condensing lens may be between the transparent substrate (23) and the backlight, and is not limited between the transparent substrate (23) and the incident side polarizing plate (33). For example, it may be on the backlight side with respect to the incident-side polarizing plate (33), and the first lens and the second lens may be disposed with the incident-side polarizing plate (33) interposed therebetween.

  The prism sheet and the condenser lens (25 and 29) may be formed integrally with other members. For example, the prism sheet may be formed integrally with the first low-refractive index layer by forming a groove on the backlight side surface of the first low-refractive index layer (31). The lens may be formed integrally with the transparent substrate by forming a groove on the backlight side surface of the transparent substrate (23).

  The condensing lens (25 and 29) is not limited to a semi-cylindrical one, and may be provided with a circular or polygonal shape when viewed in the optical axis direction. In other words, the plurality of condensing lenses are not limited to those arranged in one direction (X-axis direction), and may be arranged in two directions (X-axis direction and Y-axis direction). Further, the condensing lenses (25 and 29) are not limited to those constituted by two lenses. One lens may be sufficient and the lens group comprised by three or more lenses may be sufficient. When a condensing lens is comprised by a lens group, a condensing lens is not limited to what is comprised by combining a convex lens, A convex lens and a concave lens may be comprised suitably.

  FIG. 8 is a schematic diagram illustrating an example of a condensing lens including a concave lens.

  In this modification, the first lens 129 is a convex lens, and the second lens 125 is a concave lens. Similarly to the embodiment, the second lens 125 is arranged so that the optical axis LA12 coincides with the optical axis LA11 of the first lens 29, and the front focal point FP2 is set to the rear focal point FP1 of the first lens 29. They are arranged to match. Since the second lens 125 is a concave lens, the front focal point is located on the light emission side. Also in this modification, the light from the light guide plate is collected by the first lens 129, and the collected light is converted into parallel light by the second lens 125.

  The second lens need not convert the light collected by the first lens into completely parallel light. If the light condensed by the first lens can be made as close to parallel light as possible, the effect of improving the front luminance can be obtained. The low refractive index layer between the condensing lens and other members or between the first lens and the second lens may be omitted.

Sectional drawing which shows the liquid crystal display device which concerns on embodiment of this invention. Sectional drawing explaining an effect | action of the prism sheet of the liquid crystal display device of FIG. The figure which shows the orientation characteristic of the prism sheet of the liquid crystal display device of FIG. FIG. 2 is a diagram illustrating the configuration and operation of a condensing lens of the liquid crystal display device of FIG. 1. 2 is a flowchart showing a method for manufacturing the liquid crystal display device of FIG. The figure explaining an example of the array process of the manufacturing method of FIG. The figure explaining the other example of the array process of the manufacturing method of FIG. The figure which shows the modification of a condensing lens.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device (display apparatus), 3 ... Back light, 7 ... Light source, 9 ... Light guide plate (light guide), 13 ... Prism sheet, 13c ... Triangular prism (projection), 23 ... Incident side glass substrate (transparent Substrate), 25 ... second lens (condensing lens), 29 ... first lens (condensing lens), 39a ... translucent portion (translucent region), 39b ... reflecting portion (light-shielding region), 48 ... sub-pixel ( Pixel).

Claims (9)

A transparent substrate patterned to form a light-transmitting region and a light-shielding region in each of a plurality of pixels arranged in a predetermined direction;
A light source disposed on the back side of the transparent substrate and on one side of the predetermined direction from the plurality of pixels;
A light guide that is provided facing the back surface of the transparent substrate and guides light from the light source to the other side in the predetermined direction;
A plurality of protrusions arranged between the transparent substrate and the light guide, projecting toward the light guide, and having slopes obliquely intersecting the predetermined direction are arranged in the predetermined direction, A prism sheet that transmits light guided by the light guide to the transparent substrate side;
The transparent substrate arranged in the predetermined direction corresponding to the plurality of pixels between the transparent substrate and the prism sheet, and condensing the light transmitted through the prism sheet in the light-transmitting region of the plurality of pixels. A plurality of condensing lenses having a diameter in the predetermined direction larger than the length in the predetermined direction of the light region;
A display device. The display device according to claim 1, wherein the plurality of protrusions are provided so that two or more protrusions overlap each other in the predetermined direction with respect to each of the plurality of condenser lenses. The prism sheet transmits light from the light guide so that the peak value of luminance of the emitted light and a half value of the peak value are within a range of 20 degrees from the normal line of the prism sheet. The display device according to claim 1. Each of the plurality of condensing lenses is
A first lens that collects light that has passed through the prism sheet and has a diameter in the predetermined direction larger than the length in the predetermined direction of the translucent region;
A second lens that has a focal length shorter than that of the first lens and that emits light emitted from the first lens close to parallel light and emits the light to the translucent region;
The display device according to claim 1. The display device according to claim 4, wherein the first lens and the second lens are arranged such that a rear focal point of the first lens and a front focal point of the second lens coincide with each other. The plurality of second lenses are stacked on the light guide side, and the plurality of first lenses are stacked on the light guide side, and have a lower refractive index than the plurality of first lenses and the plurality of second lenses. The display device according to claim 4, further comprising a low refractive index layer. With respect to one surface of the transparent substrate, patterning is performed so that a plurality of pixels having a light transmitting region and a light shielding region are arranged in a predetermined direction, and with respect to the back surface of the one surface of the transparent substrate, An array step of providing a plurality of condensing lenses for condensing light from the back side on the light-transmitting regions of the plurality of pixels;
After the array step, a light source is provided on the back side of the transparent substrate and on one side of the predetermined direction with respect to the plurality of pixels, and a light guide that guides light from the light source in the predetermined direction is transparent. A prism sheet having a plurality of protrusions provided on one surface facing the back surface of the substrate, between the transparent substrate and the light guide, the one surface facing the light guide, A module step in which the plurality of protrusions are arranged in the predetermined direction and the inclined surfaces of the plurality of protrusions intersect with the predetermined direction;
A method for manufacturing a display device. The array process includes
Forming a plurality of second lenses constituting the plurality of condensing lenses by forming a resin layer on a surface of the transparent substrate on the light guide body side and pressing the resin layer with a mold;
Forming a resin layer having a lower refractive index than the plurality of second lenses on the plurality of second lenses, and pressing the resin layer with a mold to form a low refractive index layer;
On the low refractive index layer, a resin layer having a higher refractive index than the low refractive index layer is formed, and the resin layer is pressed with a mold to form a plurality of first lenses constituting the plurality of condensing lenses. And a process of
A method for manufacturing a display device according to claim 7. The array process includes
Forming a plurality of second lenses constituting the plurality of condensing lenses on the surface of the transparent substrate on the light guide side by photolithography;
Forming a low refractive index layer having a lower refractive index than the plurality of second lenses on the plurality of second lenses;
Forming a plurality of first lenses constituting the plurality of condensing lenses having a refractive index higher than that of the low refractive index layer by photolithography on the low refractive index layer;
A method for manufacturing a display device according to claim 7.

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