JP2006100182A - Surface light source and liquid crystal display using surface light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can display a three-dimensional image with high resolution and can be manufactured easily, and a surface light source suitable for it. <P>SOLUTION: A prism sheet 10 on which incident faces 10a having a plurality of narrow and long prism parts 11 arranged mutually in parallel are formed and a light absorption plate 9 are arranged with a spacing between them on the opposite side to the observation side of a liquid crystal panel 1, and a surface light source 8, in which a first and a second light source parts 13, 14 having a plurality of LEDs 13b, 14b with high directivity light distribution arranged in parallel in longitudinal direction of the narrow and long prism parts 11 are arranged, is arranged at both ends side of this spacing. By a control means 17, the image data for left eye and the image data for right eye are displayed in order on each picture element of the liquid crystal display panel 1, and as viewed from the observation side of the surface light source 8, light is emitted from the left side first light source 13 synchronized with the display of the left-eye image data, and light is emitted from the right side second light source 14 synchronized with the display of right-eye image data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface light source having directivity in a predetermined direction, and a liquid crystal display device that displays a stereoscopic image including the surface light source.

Conventionally, as a liquid crystal display device for displaying a stereoscopic image, an image for the left eye is displayed by every other column of pixels of the liquid crystal display panel, and an image for the right eye is displayed by every other column of pixels. And right-eye images are divided into the left-eye direction and the right-eye direction of the display observer for the light emitted from the pixels in one row and the light from the pixels in the other row of the liquid crystal display panel. Alternatively, the left and right eyes of the observer can be observed through a parallax barrier in which a plurality of transmissive parts and light-shielding parts parallel to the pixel rows of the liquid crystal display panel are alternately arranged. Those are known (see Patent Documents 1, 2, and 3).
Japanese Laid-Open Patent Publication No. 3-19889 Japanese Patent Laid-Open No. 7-005455 Japanese Patent Laid-Open No. 10-268230

  However, since a conventional liquid crystal display device that displays a stereoscopic image displays an image for the left eye by every other row of pixels of the liquid crystal display panel and an image for the right eye by every other row of pixels, The image resolution is low.

  Moreover, in the conventional liquid crystal display device, a lenticular lens having a lens pitch corresponding to the pixel pitch of the liquid crystal display panel, or a parallax barrier having a transmissive portion pitch corresponding to the pixel pitch, and each lens portion or transmissive portion of the lenticular lens are The pixels in each row of the liquid crystal display panel must be arranged with high precision in a predetermined positional relationship, and thus manufacturing is difficult.

  An object of the present invention is to provide a surface light source that can be easily manufactured in spite of displaying a high-resolution stereoscopic image and a liquid crystal display device including the surface light source.

The surface light source according to the present invention has an uneven surface shape in which a plurality of elongated prism portions having a mountain-shaped cross section are arranged in parallel with each other, and first and second inclined surfaces having different inclination directions are alternately connected. A prism sheet comprising an entrance surface and an exit surface that emits light incident from the entrance surface in a predetermined direction;
A first light source unit disposed on a side facing the first inclined surface in a direction orthogonal to the length direction of the elongated prism unit of the prism sheet, and emitting light toward the first inclined surface;
A second light source unit disposed on a side facing the second inclined surface in a direction orthogonal to the length direction of the elongated prism unit of the prism sheet, and emits light toward the second inclined surface; It is characterized by having.

  In this surface light source, light emitted from one of the first and second light source units is incident on the incident surface of the prism sheet, and the light is arranged in parallel on the incident surface. A direction in which light is refracted by the elongated prism portion and emitted from the emission surface, and the light from one light source portion is inclined from the emission surface of the prism sheet by a predetermined angle with respect to the normal line of the prism sheet. Can be emitted as light having directivity in which the peak of the emitted light intensity exists.

  In the surface light source according to the present invention, a space for allowing the light emitted from the light source to pass therethrough is provided on the incident surface side of the prism sheet, and the prism out of the light emitted from the first and second light sources. It is desirable that a light absorbing plate for absorbing at least a part of the light emitted in a direction other than the direction of the incident surface of the sheet is further provided, thereby obtaining outgoing light with more directivity. .

  In the surface light source of the present invention, each of the first light source unit and the second light source unit includes a plurality of solid state light emitting elements arranged in parallel in the length direction of the elongated prism portion of the prism sheet, Each solid-state light emitting element desirably has a directivity characteristic in which an angle range in which the emission light intensity is ½ is ± 7.5 °.

  Furthermore, in the surface light source according to the present invention, the prism sheet has an emission surface formed as a flat surface, and the apex angle of the triangular cross-sectional shape of the plurality of elongated prism portions formed on the incident surface is 60 ° to 80 °. The one set to the range is desirable.

  Further, a plurality of elongated convex lens portions are arranged in parallel on the exit surface side of the prism sheet, and the length direction of the plurality of elongated convex lens portions is defined as the elongated prism portion of the prism sheet. It is desirable that an anisotropic light diffusing member formed so as to be orthogonal to the length direction is further provided.

The liquid crystal display device of the present invention has a display area in which a plurality of pixels are arranged in a matrix, and the left eye image data and the right eye image data for observing with the left and right eyes on the plurality of pixels. And a liquid crystal display element that selectively displays a left-eye image and a right-eye image according to the left-eye and right-eye image data,
On the opposite side of the liquid crystal display element from the observation side, a plurality of elongated prism portions having a mountain-shaped cross section are arranged in parallel to each other, and first and second inclined surfaces having different inclination directions are alternately connected. A prism sheet having an incident surface having an uneven surface shape and an exit surface for emitting light incident from the incident surface in a predetermined direction, and orthogonal to the length direction of the elongated prism portion of the prism sheet A first light source that is disposed on the side facing the first slope in a direction to be emitted, and is orthogonal to a length direction of the elongated prism portion of the prism sheet, and a first light source that emits light toward the first slope. And a second light source that emits light toward the second slope, the length direction of the elongated prism portion on the incident surface of the prism sheet , In the left-right direction of the liquid crystal display panel A surface light source was placed in quadrature with,
Light is emitted from either one of the first and second light source units of the surface light source in synchronization with the writing of left-eye image data to the plurality of pixels of the liquid crystal display panel, and the other Control means for emitting light in synchronization with writing of right-eye image data to a plurality of pixels of the liquid crystal display panel.

  That is, in this liquid crystal display device, light from the first light source unit is emitted from the emission surface of the prism sheet on the side opposite to the observation side of the liquid crystal display panel having a display area in which a plurality of pixels are arranged in a matrix. The light is emitted as first light having directivity in which a peak of the emitted light intensity exists in a first direction inclined by a predetermined angle with respect to the normal line of the prism sheet, and is emitted from the second light source unit. The light has a directivity in which a peak of emitted light intensity exists in a second direction inclined at a predetermined angle on the opposite side to the first light with respect to the normal line from the emission surface of the prism sheet. A surface light source to be emitted as the second light is arranged.

  The liquid crystal display device sequentially writes the image data for the left eye and the image data for the right eye to each pixel of the liquid crystal display panel, and synchronizes with the writing of the image data for the left eye. Light is emitted from one of the light source unit and the second light source unit, and the light is emitted from the surface light source to the left side of the normal of the prism sheet, that is, the left eye of the display observer. The light is emitted as directivity light having a peak of emitted light intensity in a direction inclined to the direction, light is emitted from the other light source unit in synchronization with the writing of the right-eye image data, and the light is emitted. The light emitted from the surface light source as light having directivity in which there is a peak of emitted light intensity in the direction inclined to the right side of the normal of the prism sheet, that is, the direction of the right eye of the display observer, The left-eye image is displayed on the liquid crystal display panel. And sequentially displaying a right eye image and the left eye image corresponding to the data corresponding to the right-eye image data, thereby observing a stereoscopic image on the display observer.

  In the liquid crystal display device according to the present invention, the surface light source includes first and second light source sections that selectively emit light of three colors of red, green, and blue, and the control means includes one three-dimensional light source. During one frame for displaying an image, unit color image data of three colors red, green, and blue for displaying an image for the left eye and red, green, and blue for displaying an image for the right eye The unit color image data of the three colors are selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display panel, and the first and second light source units of the surface light source are viewed from the observation side of the liquid crystal display panel. Then, the light of the three colors red, green, and blue is emitted from the right light source unit in synchronization with the writing of unit color image data of the three colors red, green, and blue for displaying the left-eye image. And the red, green and blue light for displaying the right eye image from the light source on the left side. Preferably emit respectively in synchronization with the writing of the unit color image data of the color.

  In the liquid crystal display device according to the present invention, the surface light source is disposed opposite to the incident surface side of the prism sheet with a space through which light emitted from the light source passes, and is emitted from the first and second light sources. It is desirable that a light absorbing plate for absorbing at least a part of light emitted in a direction other than the direction of the incident surface of the prism sheet is further provided.

  Furthermore, in the liquid crystal display device of the present invention, a plurality of elongated convex lens portions are arranged in parallel on the light exit surface side of the prism sheet, and the length direction of the plurality of elongated convex lens portions is defined in the length direction. It is preferable that an anisotropic light diffusion member formed so as to be orthogonal to the length direction of the elongated prism portion of the prism sheet is further provided.

  Furthermore, in the liquid crystal display device of the present invention, the liquid crystal display element encapsulates a liquid crystal layer in which liquid crystal molecules are initially distributed in a homogeneous light distribution state without twisting between a pair of substrates on which opposed electrodes are formed. It is preferable from the viewpoint of response characteristics of the liquid crystal display element to apply a homogeneous liquid crystal display element.

  In the surface light source according to the present invention, the light emitted from either the first light source unit or the second light source unit is respectively arranged on the incident surface of the prism sheet. The light is directly incident on the opposite slope of the two slopes, and the light is refracted in each elongated prism part and emitted from the exit surface. Each exit light from each light source part is emitted from the prism. It is possible to emit light having directivity in which a steep peak of emitted light intensity exists in a direction inclined at a predetermined angle to the opposite side to the normal line of the prism sheet from the emission surface of the sheet.

  In the surface light source of the present invention, the intensity of the emitted light from the first light source unit in the first direction tilted from the emission surface of the prism sheet by a predetermined angle with respect to the normal line of the prism sheet. Is emitted as first light having directivity in which there is a peak of light, and light from the second light source unit is opposite to the first light with respect to the normal from the emission surface of the prism sheet. In this case, the surface light source is emitted on the side opposite to the observation side of the liquid crystal display panel. The liquid crystal display device is arranged to arrange the left-eye image data and the right-eye image data sequentially into each pixel of the liquid crystal display panel on the liquid crystal display panel, and to the plurality of pixels of the liquid crystal display panel. In synchronization with the writing of the left eye image data, Light is emitted from one of the first light source unit and the second light source unit of the surface light source, and the light is emitted from the surface light source to the left side of the normal of the prism sheet, that is, displayed. The light is emitted as directional light that has a peak of emitted light intensity in a direction inclined to the left eye of the observer, and light is emitted from the other light source unit in synchronization with the writing of image data for the right eye. The light is emitted from the surface light source as light having directivity in which the peak of the emitted light intensity exists in the direction inclined to the right side of the normal of the prism sheet, that is, the direction of the right eye of the display observer. As a result, the liquid crystal display panel uses the left eye image corresponding to the left eye image data and the right eye image corresponding to the right eye image data using all the pixels of the liquid crystal display panel. Display sequentially and stand for display observer Images can be observed.

  Therefore, according to the surface light source, a three-dimensional image with high resolution can be displayed on the liquid crystal display device, and the surface light source is provided on each of the prism sheet and both ends of the light incident surface of the prism sheet. The liquid crystal display device can be easily manufactured because of the simple configuration including the first and second light source units arranged.

  In the liquid crystal display device according to the present invention, the surface light source includes first and second light source units that selectively emit light of three colors of red, green, and blue. In one frame for displaying three stereoscopic images, unit color image data of three colors red, green, and blue for displaying an image for the left eye and red, green for displaying an image for the right eye, The blue unit color image data is selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display panel, and the observation side of the liquid crystal display panel among the first and second light source portions of the surface light source From the light source unit on the right side, the light of the three colors red, green, and blue is synchronized with the writing of unit color image data of the three colors red, green, and blue for displaying the left eye image, respectively. Red, green for displaying the right eye image from the light source on the left side. Is preferably emit respectively in synchronization with the three-color writing unit color image data of blue, by doing so, it is possible to display a high-resolution 3-D color images by the field sequential display.

  1 to 5 show a first embodiment of the present invention. FIG. 1 is an exploded perspective view of a liquid crystal display device, and FIG. 2 is a side view of the liquid crystal display device.

  As shown in FIGS. 1 and 2, the liquid crystal display device has a display area 100 in which a plurality of pixels (not shown) are arranged in a matrix, so that the pixels can be observed with separate left and right eyes. The left-eye image data and the right-eye image data are selectively written, and the left-eye image and the right-eye image are selectively displayed according to the left-eye and right-eye image data. A display panel 1, a surface light source 8 disposed on the opposite side of the liquid crystal display panel 1 from the observation side (upper side in the figure), and a control means 17 for driving the liquid crystal display panel 1 and the surface light source 8 are provided. ing.

  The liquid crystal display panel 1 is an active matrix liquid crystal display panel using TFTs (thin film transistors) as active elements, and the internal structure thereof is not shown, but a pair of transparent substrates 2 and 3 bonded via a frame-shaped sealing material. A plurality of transparent pixel electrodes arranged in a matrix in the row direction and the column direction on one substrate, for example, the inner surface of the substrate 2 on the opposite side to the observation side, and the pixel electrodes respectively A plurality of connected TFTs, a plurality of gate lines for supplying gate signals to the TFTs in each row, and a plurality of gate lines for supplying gate signals to the TFTs in each column are provided, and the other observation side substrate 3 is provided. A single-film transparent counter electrode forming a plurality of pixels arranged in a matrix form on the inner surface of each of the plurality of pixel electrodes. The liquid crystal layer is provided in a region surrounded by the sealing material between the substrates 2 and 3, and the polarizing plates 4 and 5 are disposed on the outer surfaces of the pair of substrates 2 and 3, respectively. Yes.

  The liquid crystal display panel 1 is a non-twisted homogeneous alignment type liquid crystal display panel in which the liquid crystal molecules of the liquid crystal layer are aligned homogeneously with the molecular long axis aligned in one direction, and on the outer surfaces of the pair of substrates 2 and 3, A pair of polarizing plates 4 and 5 are arranged so that their transmission axes are substantially orthogonal or parallel to each other. The liquid crystal display panel 1 is not limited to a homogeneous alignment type liquid crystal display panel, and other various light distribution operation mode liquid crystal display panels can be used. For example, the liquid crystal molecules of the liquid crystal layer are used as a pair of substrates 2. , 3 is a TN (twisted nematic) liquid crystal display panel with a twist distribution of light at a substantially 90 ° twist angle, and a pair of polarizing plates 4 and 5 are arranged with their transmission axes substantially orthogonal or parallel to each other. It is good also as composition to do.

  On the substrate 2 opposite to the viewing side of the liquid crystal display panel 1, driver mounting portions 2a and 2b are formed on one end edge in the row direction and one end edge in the column direction. The plurality of gate wirings are connected to a gate side driver 6 mounted on the driver mounting portion 2a in the row direction, and the plurality of data wirings are connected to the data side mounted on the driver mounting portion 2b in the column direction. The counter electrode is connected to the driver 7, and the gate electrode is connected to the gate via a cross connection portion provided in a substrate bonding portion made of the sealing material and a counter electrode connection wiring formed in one or both of the driver mounting portions 2 a and 2 b. It is connected to the reference potential of one or both of the side driver 6 and the data side driver 7.

  The surface light source 8 has a peak of emitted light intensity in a first direction inclined at a predetermined angle in the direction of one of the left and right eyes of the display observer with respect to the normal line of the liquid crystal display panel 1. Directivity in which there is a first light beam having a directivity and a peak of emitted light intensity in a second direction inclined at a predetermined angle in the direction of the other eye of the observer with respect to the normal line. The surface light source 8 is emitted to the light absorption plate 9 and the light incident surface (upper surface in the drawing) of the light absorption plate 9. The prism sheet 10 is disposed so as to face each other, and the first and second light source sections 13 and 14 are included.

  The light absorbing plate 9 of the surface light source 8 is formed integrally with a surface light source housing (not shown) that supports the first and second light source portions 13 and 14 and the prism sheet 10 and the like. The inner surface of the base plate (the surface facing the prism sheet 10) covering the back surface of the prism sheet together with the light source sections 13 and 14 is colored black with, for example, paint, and the entire display area 100 of the liquid crystal display panel 1 Has a sufficiently opposite area. The color of the light incident surface of the light absorbing plate 9 is not limited to black, but may be colored to an optimum color for obtaining display quality required for a liquid crystal display device.

  The prism sheet 10 includes a plurality of elongated prisms having a transverse cross section forming an isosceles triangle on one surface of a transparent sheet made of an acrylic resin having an area facing the entire display area 100 of the liquid crystal display panel 1. An incident surface 10a having a concavo-convex surface shape in which first and second inclined surfaces having different inclination directions are alternately arranged is formed by arranging the portions 11 in parallel with each other, and the incident surface is formed on the other surface. A flat emission surface 10b for emitting light incident from the surface 10a is formed, and the thickness d of the portion of the prism sheet 10 excluding the plurality of elongated prism portions 11 is about 200 μm, and the plurality of elongated prisms. The apex angle α of the portion 11 is set in the range of 60 ° to 80 °.

  In the figure, for convenience, the plurality of elongated prism portions 11 are greatly exaggerated, but these elongated prism portions 11 are densely arranged at a pitch P that is approximately equal to or less than the pixel pitch of the liquid crystal display panel 1. It is formed side by side. The pitch P of the plurality of elongated prism portions 11 is in the range of 30 μm to 150 μm, preferably 40 μm to 60 μm.

  The prism sheet 10 is arranged such that the incident surface 10a on which the plurality of elongated prism portions 11 are formed is opposed to the light absorbing plate 9, and a space is provided between the prism sheet 10 and the light absorbing plate 9. The height H of the portion corresponding to the top of the elongated prism portion 11 in the space between the light absorbing plate 9 and the prism sheet 10 is set in the range of 2 mm to 7 mm, preferably 4 mm to 6 mm.

  The first and second light source parts 13 and 14 are arranged at both end sides in a direction orthogonal to the length direction of the elongated prism part 11 in the space between the light absorbing plate 9 and the prism sheet 10. Respectively.

  The first and second light source parts 13 and 14 are respectively provided on a plurality of solid light emitting elements 13b on strip-like substrates 13a and 14a having the same length as the plurality of elongated prism parts 11 of the prism sheet 10. 14b are juxtaposed in the longitudinal direction with substantially no gap. Although not shown in the drawings, wirings and contacts for electrically connecting the solid light emitting elements 13b and 14b in parallel are arranged on the substrates 13a and 14a, respectively.

  The solid light emitting elements 13b and 14b are solid light emitting elements having a steep directivity required for light distribution characteristics. In the present embodiment, a round light emitting diode (hereinafter referred to as an LED (Light Emitting Diode)) is respectively The light source sections 13 and 14 are arranged in parallel at a pitch of 5 mm. As shown in FIG. 3, the round LEDs 13b and 14b have emission light distribution characteristics with extremely high directivity. That is, the angle range in which the emission light intensity is ½ has a directivity characteristic of ± 7.5 ° to ± 10 °, that is, the half-value width is ± 7.5 ° to ± 10 °, and is within a narrow angle range. It has an emission light distribution characteristic that can be emitted.

  The first and second light source units 13 and 14 configured as described above are installed at both ends of the light absorbing plate 9 with the substrates 13a and 14a inclined at a predetermined angle with respect to the surface of the light absorbing plate 9, respectively. Has been. As shown in FIG. 2, the inclination angle is emitted from the LEDs 13b and 14b with respect to the plane direction in which the emission surfaces 10a of the liquid crystal display panel 1 and the prism sheet 10 of the principal rays extend in parallel. The angle θ is set to be 1 to 20 °. In addition, the inclination angle θ of the principal ray is more preferably 5 to 10 ° even in the angle range of 1 to 20 °, and most preferably about 7 °.

  In the surface light source 8, the light having the directivity shown in FIG. 3 from the first and second light source units 13 and 14 constitutes an incident surface 10 a that forms the concave and convex surface shape of the prism sheet 10. The elongated prism 11 is emitted toward the slopes 11a and 11b on the side facing the light source portions 13 and 14 of the first and second slopes 11a and 11b having different tilt directions. The emitted light passes through the space between the light absorbing plate 9 and the prism sheet 10 and is incident on the first or second inclined surface 11a, 11b on the opposite side, and these incident lights are incident. The light is emitted from the light exit surface 10 b of the prism sheet 10 through the optical actions of refraction and total reflection in each elongated prism portion 11. At this time, the light emission direction and the angle φ with respect to the normal line n of the emission surface 10 b differ depending on the apex angle α of the elongated prism portion 11.

  In the present embodiment, as described above, the apex angle α of the elongated prism portion 11 is set in a range of 60 ° to 80 °, and among them, the apex angle α is set to 60 ° ≦ α ≦ 70 °. In this case, the highly directional light source light emitted from the first light source unit 13 is the first on the opposite side as shown in FIG. 4A and FIG. After being incident on the inclined surface 11a and being subjected to a refracting action based on the difference in refractive index between the prism and air at this time, the light is totally reflected by the second inclined surface 11b opposite to the incident inclined surface, and is emitted from the exit surface 10b. Emitted. At the time of the emission, a refraction action based on the difference in refractive index between the prism and the air is received again, and only the angle φ set in advance on the first light source unit 13 side of the emission source with respect to the normal line n of the prism sheet 10. The light is emitted as the first light R1 having high directivity in which the peak of the emitted light intensity exists in the inclined first direction. On the other hand, as shown in FIG. 4C, the light emitted from the second light source unit 14 is incident on the second inclined surface 11b on the opposite side, and is similarly refracted and totally reflected in the prism sheet 10. A high directivity in which the peak of the emitted light intensity exists in the second direction inclined by a predetermined angle φ from the emission surface 10b to the emission source second light source unit 14 side with respect to the normal line n. The second light R2 having the characteristic is emitted.

  Incidentally, when the emission angle θ of the principal ray emitted from the first light source 13 is 10 °, the refractive index of the prism sheet 10 is 1.49, and the apex angle α of the elongated prism portion 11 is 68 degrees, the emitted light R1. Is about + 7 ° (normal line n is 0 °, and the case where it is inclined toward the first light source unit 3 is +). Under the same conditions, the emission angle φ of the outgoing light R2 emitted from the second light source 14 and incident on the prism sheet 10 and emitted is about -7 °.

  In addition, since the processing accuracy of the prism sheet 10 is limited, some generation of light that does not follow the intended optical path due to variations in processing accuracy, that is, stray light is unavoidable. In the embodiment, since the light absorbing plate 9 is provided, such stray light can be absorbed without being reflected toward the prism sheet 10 when entering the light absorbing plate 9. As a result, crosstalk emission emitted in the direction inclined to the opposite side to the direction in which the light emitted from each light source part should be emitted, that is, the opposite side to the light source part of the emission source is prevented. The directivity of the second outgoing lights R1 and R2 is further increased.

  FIG. 5 shows the light distribution characteristics of the first and second outgoing lights R1 and R2 having a remarkably high directivity. From the first and second light source units 13 and 14 in which the round LEDs 3b and 4b having the high directivity light distribution characteristic shown in FIG. 3 are arranged in parallel, all the inclined surfaces 11a and 11b on the opposite side are respectively connected. Highly directional light having a half-value output light emission range of ± 7.5 ° is emitted substantially uniformly toward the light source, and stray light is absorbed by the light absorbing plate 9. As shown in the figure, each of the two outgoing lights R1 and R2 has a peak of output (light intensity) that is remarkably steep in the direction where the outgoing angle φ is ± 7 °, and the normal line n of the prism sheet 10 is present. On the other hand, the light having a light distribution characteristic in which the light intensity emitted in the direction opposite to the peak direction of the emitted light intensity is close to zero.

  On the other hand, when the apex angle α of the triangular prism portion 11 is set to 70 ° <α ≦ 80 °, the light emitted from the first light source portion 13 as shown in FIGS. As shown in FIG. 6 (a) and FIG. 6 (b) showing the elongated prism portion in an enlarged manner, the incident angle in the prism sheet 10 is the same as in the case where the apex angle α is 60 ° ≦ α ≦ 70 °. In response to the refracting action and the total reflection action, a first angle inclined by a predetermined angle δ from the exit surface 10b to the side opposite to the first light source 13 side of the emission source with respect to the normal line n of the prism sheet 10. The first light R1 having directivity in which the peak of the emitted light intensity exists in the direction 1 is emitted. On the other hand, the light emitted from the second light source unit 14 is emitted from the emission surface 10b of the prism sheet 10 with respect to the normal line n, as shown in FIG. 6C. The light is emitted as the second light R2 having directivity in which the peak of the emitted light intensity exists in the second direction inclined by a predetermined angle δ to the opposite side to the side.

  Incidentally, when the emission angle θ of the principal ray emitted from the first light source 13 is 10 °, the refractive index of the prism sheet 10 is 1.49, and the apex angle α of the elongated prism portion 11 is 75 °, the emitted light R1. The emission angle φ of the lens is about −7 °. Under the same conditions, the emission angle φ of the outgoing light R2 emitted from the second light source 14 and incident on the prism sheet 10 and emitted is about + 7 °. Therefore, the light distribution characteristics of the outgoing lights R1 and R2 in this case are substantially the same as those in the case where the apex angle α shown in FIG. 5 is 68 °, only the outgoing lights R1 and R2 are replaced. .

  As described above, according to the surface light source 8 of the present embodiment, the LEDs 13 b and 14 b having the above-described highly directional emission light distribution characteristics are parallel to the length direction of the elongated prism portion 11 at both ends of the prism sheet 10. The first and second light source parts 13 and 14 are arranged in parallel over substantially the same distance, and highly directional light is emitted from the respective light source parts 13 and 14 toward the opposing slopes 11a and 11b. Therefore, light is emitted directly and substantially evenly from the light source units 13 and 14 facing each of the inclined surfaces 11a and 11b of the incident surface 10a of the prism sheet 10. Further, since the light absorbing plate 9 is disposed so as to face the incident surface 10a, stray light can be efficiently absorbed. As a result, the light source has a steep light intensity peak in the direction inclined by a required angle toward the light source parts 13 and 14 with respect to the normal line n of the emission surface 10b, and there are few portions where the emission directions overlap each other and the separation is high. First and second outgoing lights R1 and R2 of light distribution (see FIG. 5) are obtained. In addition, the light utilization efficiency is increased in combination with the direct incidence of the light source light on the incident surface 10a, and the luminance of the respective planar emitted light composed of the emitted lights R1 and R2 is also increased.

  The surface light source 8 described above is arranged on the side opposite to the viewing side of the liquid crystal display panel 1 to constitute a liquid crystal display device. The left-eye image data and the right-eye image to a plurality of pixels of the liquid crystal display panel 1 are configured. In synchronism with selective writing of image data, a first direction inclined from the surface light source 8 to one of the normal lines n of the exit surface 10b of the prism sheet 10, that is, left and right of the display observer. First light having directivity in which a peak of emitted light intensity exists in a direction inclined at a predetermined angle to the direction of one of the eyes, and a normal line n of the emission surface 10b of the prism sheet? 0 Second light having directivity in which the peak of the emitted light intensity exists in a second direction inclined to the other side, that is, a direction inclined at a predetermined angle to the direction of the other eye of the observer. By exiting toward the liquid crystal display panel 1, the liquid crystal display panel is emitted. The left eye image corresponding to the left eye image data and the right eye image corresponding to the right eye image data are sequentially displayed on the channel 1 using all the pixels of the liquid crystal display panel 1, respectively. It is possible to make a display observer observe a stereoscopic image.

  Therefore, according to the surface light source 8, a high-resolution stereoscopic image can be displayed on the liquid crystal display device, and the surface light source 8 is provided between the light absorbing plate 9 and the light absorbing plate 9. And the first and second light source sections 13 and 14 disposed on both ends of the space between the light absorbing plate 9 and the prism sheet 10, respectively. Due to the simple configuration, the liquid crystal display device can be easily manufactured.

  As shown in FIGS. 1 and 2, the surface light source 8 has an emission surface 10 b of the prism sheet 10 opposed to the liquid crystal display panel 1 on the side opposite to the observation side of the liquid crystal display panel 1, and A direction perpendicular to the length direction of the elongated prism portion 11 on the incident surface 10 a of the prism sheet 10 is arranged in the left-right direction of the liquid crystal display panel 1.

  In the present embodiment, the surface light source 8 is directed leftward when the arrangement side of the first light source unit 13 is viewed from the observation side of the liquid crystal display panel 1, and the arrangement side of the second light source unit 14 is arranged from the observation side. The light beam from the first light source unit 13 is directed toward the right side when viewed from the emission surface 10b of the prism sheet 10 and has a peak of emitted light intensity in the direction of the left or right eye of the display observer. The first directional light having the characteristic is emitted, and the light from the second light source unit 14 has a peak of the emitted light intensity from the emission surface 10b of the prism sheet 10 toward the other eye of the display observer. The light is emitted as the second directional light having the existing directivity.

  Next, the control means 17 for driving the liquid crystal display panel 1 and the surface light source 8 will be described. In the following description, the apex angle α of the elongated prism portion 11 in the prism sheet 10 is set to 60 ≦ α ≦ 70. It is explained as having been done. Of the first and second light source units 13 and 14 of the surface light source 8, the first light source unit 13 on the left side (right side in FIGS. 1 and 2) viewed from the observation side of the liquid crystal display panel 1 is used. The light source unit for the left eye is referred to as the second light source unit 14 on the right side (the left side in FIGS. 1 and 2) when viewed from the observation side.

  Although the specific configuration of the control means 17 is not shown, the write control circuit for controlling the gate side driver 6 and the data side driver 7 of the liquid crystal display panel 1, the left eye light source unit 13 of the surface light source 8, The illumination control circuit controls the emission of light from the right-eye light source unit 14 (lighting of the LEDs 13b and 14b).

  The control means 17 sequentially writes left-eye image data and right-eye image data for observation with the left and right eyes to each pixel of the liquid crystal display panel 1, and the first and second of the surface light source 8. Of the light source units 13 and 14, the first light source unit on the left side when viewed from the observation side of the liquid crystal display panel 1, that is, the light source unit 13 for the left eye, is synchronized with the writing of the image data for the left eye. Is emitted in synchronism with the writing of the right-eye image data from the right second light source unit, that is, the right-eye light source unit 13b as viewed from the observation side.

  In this embodiment, each of the first and second light source units 13 and 14 of the surface light source 8 has three types of red LEDs that emit red light, green LEDs that emit green light, and blue LEDs that emit blue light. LED 3b and 4b are provided, and the control means 17 has unit color image data of three colors of red, green and blue for displaying a left eye image during one frame for displaying one stereoscopic image. And unit image data of three colors of red, green, and blue for displaying an image for the right eye are selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display panel 1, and the first light source 8 of the surface light source 8 is selected. And the second light source units 13 and 14, the left eye light source unit 13 emits light of the three colors red, green, and blue from the left eye light source unit 13 when viewed from the observation side of the liquid crystal display panel 1. Same as writing unit color image data of red, green and blue to display The right-eye light source unit 14 on the right side as viewed from the observation side emits light of the three colors of red, green, and blue, red, green, and blue 3 for displaying the right-eye image. The color unit color image data is output in synchronism with the writing.

  The unit color image data of three colors red, green, and blue for displaying the left eye image and the unit color image data of three colors red, green, and blue for displaying the right eye image are, for example, , Image data of red, green, and blue color components by a left lens of a color image captured by a digital camera having two left and right imaging lenses arranged at predetermined intervals, and each color of red, green, and blue by a right lens Component image data.

  In this liquid crystal display device, unit color image data of three colors red, green, and blue for displaying an image for the left eye is displayed by the control means 17 during one frame for displaying one stereoscopic image. Unit color image data of three colors red, green, and blue for displaying an image for the right eye is selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display panel 1, and the surface light source is controlled by the control means 17. 8 controls the lighting of the LEDs 13b and 14b of the left-eye light source unit 13 and the right-eye light source unit 14, and corresponds to unit color image data written from the surface light source 8 to each pixel of the liquid crystal display panel 1. By emitting the planar emission light having the color and directivity to be synchronized with the writing of the unit color image data, a red image, a green image, a blue image for the left eye during the one frame, and With red, green and blue images for the right eye Sequentially displayed six unit color images in a predetermined order.

  That is, this liquid crystal display device forms one frame for displaying one stereoscopic image with six fields, and for each field, a red image for the left eye, a green image for the left eye, a blue image for the left eye, Field sequential display is performed for sequentially displaying one of six unit color images of a right-eye red image, a right-eye green image, and a right-eye blue image in an arbitrary order. The six unit color images can be displayed using all the pixels of the liquid crystal display panel, and a three-dimensional color image in which the six unit color images appear to overlap can be observed. An image can be displayed.

  In this liquid crystal display device, it is preferable to set the 1 frame to 1/30 seconds or less and the 1 field to 1/180 seconds or less. An image can be displayed.

  In addition, the liquid crystal display device can be easily manufactured because the configuration of the surface light source 8 is simple as described above.

  When the apex angle α of the elongated prism portion 11 in the prism sheet 10 is 70 <α ≦ 80, the first light source portion 13 is a right eye light source portion, and the second light source portion 14 is a left eye light source portion. The operation for displaying the stereoscopic image is the same as that in the case where the vertex angle α is 60 ≦ α ≦ 70.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a side view of the liquid crystal display device of FIG. 7 viewed from the second light source unit 14 side with the first light source unit 13 side omitted. Moreover, the same code | symbol is attached | subjected about the component same as the said embodiment, and the description is abbreviate | omitted.

  FIG. 7 is an exploded perspective view showing the liquid crystal display device as the second embodiment. In the surface light source 20 used in the liquid crystal display device of the present embodiment, the prism sheet 10 has the same exit surface 10b side as the prism sheet 10. An anisotropic light diffusion sheet 21 that diffuses light in a uniaxial direction formed of a transparent material is installed. The anisotropic light diffusing sheet 21 has substantially the same area as the prism sheet 10 and has a plurality of elongated convex lens portions 22 arranged in parallel like a lenticular lens. As shown in FIG. 21a and a concavo-convex emission surface 21b in which an elongated curved convex surface is connected. The anisotropic light diffusing sheet 21 has its incident surface 21 a opposed to the exit surface 10 b of the prism sheet 10, and the length direction of the elongated lens portion 22 is orthogonal to the length direction of the elongated prism portion 11 of the prism sheet 10. Are arranged. The parallel pitch of the elongated lens portions 22 in this embodiment is set to 40 μm.

  In the liquid crystal display device of the present embodiment, the planar emission light emitted from the prism sheet 10 of the surface light source 20 is transmitted through the anisotropic light diffusion sheet 21, whereby the luminance corresponding to the arrangement of the LEDs 13b and 14b as the light sources. The planar emission light is free from unevenness. The reason for this will be described with reference to FIG. 8 for the light emitted from the first light source unit 13.

  On the exit surface 10b of the prism sheet 10, in the direction orthogonal to the length direction of the elongated prism portion 11, the first exit light R1 having the light distribution characteristics shown in FIG. However, in the length direction of the elongated prism portion 11, that is, the direction in which the LEDs 13b of the light source portion 13 are arranged in parallel, the light emitted from the LEDs 13b has the highly directional light distribution characteristic shown in FIG. As shown in FIG. 5, the emitted lights of the emitted lights of the adjacent LEDs 13b are emitted without overlapping substantially in parallel. Therefore, when the light emitted from the first light source unit 13 is emitted from the prism sheet 10, it becomes planar emission light having luminance unevenness corresponding to the arrangement of the LEDs 13 b in the length direction of the elongated prism unit 11. ing.

  When the planar emission light having such luminance unevenness is transmitted through the anisotropic light diffusion sheet 21, only in a direction orthogonal to the length direction of the elongated lens portion 22 as illustrated, due to the lens effect of the elongated lens portion 22. Diffused. This is because the parallel pitch of the elongated lens portions is 40 μm, which is sufficiently smaller than the parallel pitch of the LEDs 13b. However, the light distribution characteristic shown in FIG. 5 is maintained in the longitudinal direction of the elongated lens portion 22. As a result, the emitted lights R1 of the lights emitted from the adjacent LEDs 13b of the first light source unit 13 sufficiently overlap each other.

  Therefore, the planar emission light R1 emitted from the emission surface 21b of the anisotropic light diffusion sheet 21 based on the light emitted from the first light source unit 13 has a steep light intensity peak in the intended direction in FIG. The planar emission light suitable for the backlight of the display device in which the uneven luminance due to the arrangement of the light source is eliminated while the high light distribution directivity shown is ensured is formed. The same applies to the light emitted from the other second light source unit 14.

  As described above, in the surface light source 20 of the present embodiment, the anisotropic light diffusion sheet in which the plurality of elongated lens portions 22 are arranged in parallel at a sufficiently small pitch on the light emission side of the surface light source 8 of the above-described embodiment. 21 is arranged in such a manner that the length direction of the elongated lens portion 22 is orthogonal to the arrangement direction of the plurality of LEDs 13b, 14b constituting the light source portions 13, 14, ensuring the desired high light distribution directivity. In this way, each planar emission light composed of the first and second emission lights R1 and R2 in which the luminance unevenness due to the arrangement of the LEDs 13b and 14b of the light source sections 13 and 14 is eliminated is obtained. Accordingly, there is a steep emission light intensity peak in the direction of the left and right eyes of the observer, and planar emission light having no luminance unevenness is emitted toward the liquid crystal display element 1 in the vertical viewing angle direction of the observer. A high-resolution three-dimensional image with good image quality is displayed.

The present invention is not limited to the above embodiment.
For example, in the surface light sources 8 and 20 of the first and second embodiments, both the first and second directional emitted lights are inclined in a direction inclined by about 7 ° with respect to the normal line n of the prism sheet 10. Although the output light intensity peak is designed to exist, the direction in which the emission light intensity peaks of the first and second directional lights exist is the display observation distance depending on the use of the liquid crystal display device. Accordingly, the direction in which the intensity peaks of the left-eye illumination light and the right-eye illumination light exist may be designed to coincide with the direction toward the left and right eyes of the display observer. What is necessary is just to set the apex angle (alpha) of the some elongate prism part 11 of the entrance plane 10a of the prism sheet 10. FIG.

  The liquid crystal display device of the above embodiment uses the liquid crystal display panel 1 that does not include a color filter, and for the left eye that selectively emits light of three colors of red, green, and blue to the surface light sources 8 and 20. By providing the right-eye light source sections 13a and 13b, a stereoscopic color image is displayed by field sequential display. The present invention provides a liquid crystal display panel with a plurality of colors corresponding to the plurality of pixels, for example, The present invention can also be applied to a liquid crystal display device that includes color filters of three colors of red, green, and blue and that includes a light source for left eye and right eye that emits white light to the surface light sources 8 and 20. In that case, the left-eye image data and the right-eye image data are sequentially written to each pixel of the liquid crystal display panel, and the left-eye image data is written from the left-eye light emitting element of the surface light source. Synchronize The left eye color image and the right eye color image are alternately displayed sequentially by emitting light from the light emitting element for the right eye in synchronization with the writing of the image data for the right eye. What is necessary is just to observe the three-dimensional image which these images appear to overlap.

  Furthermore, the prism sheet 10 and the anisotropic light diffusion sheet 21 in the surface light source 20 of the second embodiment may be combined into one member, thereby reducing the number of members and the number of manufacturing steps.

  In addition, the light absorbing plate 9 may be a base plate as a simple member of the housing not provided with the light absorbing layer.

1 is an exploded perspective view showing a liquid crystal display device as a first embodiment of the present invention. It is a side view of the liquid crystal display device. It is an emission light distribution characteristic view of LED used as a light emitting element in the liquid crystal display device. (A) is a figure which shows the emission path | route of the 1st light from the surface light source of the said liquid crystal display device, (b) is a fragmentary detailed view which expands and shows an elongate prism part, (c) is the 2nd light of FIG. It is a figure which shows an output route. The light distribution characteristic view of the 1st and 2nd emitted light radiate | emitted from the said surface light source. (A) is a figure which shows the emission path | route of the 1st light at the time of changing a prism apex angle with the surface light source of the said liquid crystal display device, (b) is a partial detail figure which expands and shows an elongate prism part, (c) ) Is a diagram showing an emission path of the second light. It is a disassembled perspective view which shows the surface light source as 2nd Embodiment of this invention. It is a side view of the surface light source.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display panel, 100 ... Display area, 8, 20 ... Surface light source, 9 ... Light absorption board, 10 ... Prism sheet, 10a ... Incident surface, 10b ... Outgoing surface, 11 ... Elongate prism part, 13, 14 ... Light source Part, 13b, 14b ... LED, 17 ... control means, 21 ... anisotropic light diffusion sheet, 22 ... elongate lens part.

Claims (10)

A plurality of elongated prism portions each having a mountain-like cross section, arranged in parallel with each other, and an incident surface having an uneven surface shape in which first and second inclined surfaces having different inclination directions are alternately connected; and the incident surface A prism sheet provided with a light exit surface that emits light incident from a predetermined direction;
A first light source unit disposed on a side facing the first inclined surface in a direction orthogonal to the length direction of the elongated prism unit of the prism sheet, and emitting light toward the first inclined surface;
A second light source unit disposed on a side facing the second inclined surface in a direction orthogonal to the length direction of the elongated prism unit of the prism sheet, and emits light toward the second inclined surface;
A surface light source characterized by comprising:   On the incident surface side of the prism sheet, there is provided a space for allowing the light emitted from the light source to pass therethrough. Out of the light emitted from the first and second light sources, the direction of the incident surface of the prism sheet 2. The surface light source according to claim 1, further comprising a light absorbing plate for absorbing at least a part of light emitted in a direction other than the above.   Each of the first light source section and the second light source section includes a plurality of solid light emitting elements arranged in parallel in the length direction of the elongated prism section of the prism sheet, and each solid light emitting element emits light. 3. The surface light source according to claim 1, wherein the surface light source has a directivity characteristic in which an angle range in which the intensity is ½ is ± 7.5 °.   In the prism sheet, the exit surface is formed as a flat surface, and the apex angle of the triangular cross-sectional shape of the plurality of elongated prism portions formed on the entrance surface is set in a range of 60 ° to 80 °. The surface light source according to any one of claims 1 to 3.   For the prism sheet, a plurality of elongated convex lens portions are arranged in parallel on the exit surface side, and the length direction of the plurality of elongated convex lens portions is the length direction of the elongated prism portion of the prism sheet. The surface light source according to claim 1, further comprising an anisotropic light diffusion member formed so as to be orthogonal to the surface. The display area has a plurality of pixels arranged in a matrix, and left-eye image data and right-eye image data for observation with separate left and right eyes are selectively written into the plurality of pixels. A liquid crystal display element that selectively displays a left-eye image and a right-eye image according to the left-eye and right-eye image data;
On the opposite side of the liquid crystal display element from the observation side, a plurality of elongated prism portions having a mountain-shaped cross section are arranged in parallel to each other, and first and second inclined surfaces having different inclination directions are alternately connected. A prism sheet having an incident surface having an uneven surface shape and an exit surface for emitting light incident from the incident surface in a predetermined direction, and orthogonal to the length direction of the elongated prism portion of the prism sheet A first light source that is disposed on the side facing the first slope in a direction to be emitted, and is orthogonal to a length direction of the elongated prism portion of the prism sheet, and a first light source that emits light toward the first slope. And a second light source that emits light toward the second slope, the length direction of the elongated prism portion on the incident surface of the prism sheet , In the left-right direction of the liquid crystal display panel A surface light source was placed in quadrature with,
Light is emitted from either one of the first and second light source units of the surface light source in synchronization with the writing of left-eye image data to the plurality of pixels of the liquid crystal display panel, and the other And a control means for emitting light in synchronization with writing of the right-eye image data to the plurality of pixels of the liquid crystal display panel.   The surface light source includes first and second light source units that selectively emit light of three colors of red, green, and blue, and the control unit has one frame for displaying one stereoscopic image. Between the unit color image data of three colors red, green, and blue for displaying the image for the left eye and the unit color image data of three colors red, green, and blue for displaying the image for the right eye, Are selected in an arbitrary order and sequentially written to each pixel of the liquid crystal display element, from among the first and second light source parts of the surface light source, from the right light source part as viewed from the observation side of the liquid crystal display element, The light of three colors of red, green, and blue is emitted in synchronization with writing of unit color image data of three colors of red, green, and blue for displaying the image for the left eye, and from the light source unit on the left side, Writing the unit color image data of the three colors of red, green, and blue to display the image for the right eye with the light of the three colors of red, green, and blue It is a liquid crystal display device according to claim 6 or claim 6, characterized in that emit in synchronism.   The surface light source is disposed opposite to the incident surface side of the prism sheet with a space through which the light emitted from the light source passes, and the light incident surface of the prism sheet out of the light emitted from the first and second light sources. The liquid crystal display device according to claim 6, further comprising a light absorbing plate for absorbing at least a part of light emitted in a direction other than the direction of 8.   For the prism sheet, a plurality of elongated convex lens portions are arranged in parallel on the exit surface side, and the length direction of the plurality of elongated convex lens portions is the length direction of the elongated prism portion of the prism sheet. The liquid crystal display device according to claim 6, further comprising an anisotropic light diffusion member formed so as to be orthogonal to the liquid crystal display device.   The liquid crystal display element is a homogeneous liquid crystal display element in which a liquid crystal layer in which liquid crystal molecules are initially aligned in a homogeneous alignment state without twist is sealed between a pair of substrates on which opposing electrodes are formed. The liquid crystal display element in any one of Claim 6 thru | or 9.

Images