JP4654944B2 - LIGHTING DEVICE, ELECTRO-OPTICAL DEVICE, AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to an illumination device that can be suitably used for an in-vehicle electro-optical device.

  Conventionally, in a liquid crystal device having a transmissive display mode, a backlight unit as an illumination device is provided on the back side of the liquid crystal panel. As this type of backlight unit, a light source composed of a cold-cathode tube or a light-emitting diode, which is disposed on the side end face of a transparent light guide plate, and light from the light source to the liquid crystal panel side as planar light In general, the light guide plate is configured to be provided.

  In order to increase the display brightness of this type of liquid crystal device, a backlight unit is provided by providing a prism sheet in which a large number of prisms having a triangular cross section are periodically formed on the upper side of the light guide plate on the liquid crystal panel side. For example, Patent Document 1 discloses a technique for improving the utilization efficiency of light from a light source.

  In addition, there is known a method for expanding the viewing angle of a liquid crystal display, in which two or more microlens array sheets having a refractive index of the observation surface side material of 1.30 or more are mounted on the observation surface side of the liquid crystal cell (for example, (See Patent Document 2).

Japanese Patent Laid-Open No. 6-18879 JP 7-43704 A

  In the liquid crystal device having the prism sheet as described above, the peak of display luminance is set in the normal direction (front direction) to the display surface of the liquid crystal panel due to the prism shape of the prism sheet. Therefore, when such a liquid crystal device is used as an in-vehicle liquid crystal panel such as a navigation system, and the liquid crystal device is installed near the dashboard located at the center of the driver side and the passenger side, the liquid crystal panel Although the display brightness in the normal direction (front direction) with respect to the display surface is large, there is a problem that the display brightness on the driver's seat side and the passenger seat side where the passenger is present becomes small. For this reason, there has been a problem that the liquid crystal device cannot be suitably used as an in-vehicle liquid crystal panel.

  The present invention has been made in view of the above points, and is an illumination that can increase display luminance with respect to viewpoints such as a driver's seat and a passenger's seat when used as an in-vehicle electro-optical panel. It is an object of the present invention to provide a device and an electro-optical device using the device.

In one aspect of the present invention, the illuminating device includes a light source, a light guide plate having a light output surface for emitting light emitted from the light source, and a plurality of light sources facing the light guide plate and facing the light guide plate side. A first prism sheet having a first prism pattern provided with a first linear prism, and a plurality of second lines facing the first prism sheet and facing the first prism sheet side A second prism sheet having a second prism pattern provided with a prism, and light emitted from the first prism sheet has a luminance in a direction intersecting a ridge line of the first linear prism. However, the end portion is higher than the center portion of the first prism sheet.

  The illumination device can be suitably used as, for example, a backlight unit of an electro-optical device, and has a light source, a light guide plate having a light output surface for emitting light emitted from the light source, and the light guide plate. A first prism sheet having a first prism pattern having a plurality of first linear prisms facing the light guide plate side, and facing the first prism sheet, the first prism sheet And a second prism sheet having a second prism pattern having a plurality of second linear prisms facing the prism sheet side.

Here, since the first prism sheet has a plurality of first linear prisms facing the light guide plate on the side facing the light guide plate, the light emitted through the light exit surface of the light guide plate is the same as the light guide plate. Light can be emitted to the opposite side, that is, the second prism sheet side. Further, since the second prism sheet has a plurality of second linear prisms facing the first prism sheet side on the side facing the first prism sheet, the light is emitted from the first prism sheet side. The light can be divided into two directions by the two inclined surfaces of the linear prism. Therefore, the luminance and the viewing angle with respect to the two directions can be increased. In addition, the light emitted from the first prism sheet has higher luminance in the direction intersecting the ridge line of the first linear prism at the end than at the center of the first prism sheet. Is preferred.
In another aspect of the present invention, the illuminating device includes a light source, a light guide plate having a light output surface that emits light emitted from the light source, and a plurality of light sources facing the light guide plate and facing the light guide plate side. A first prism sheet having a first prism pattern provided with a first linear prism, and a plurality of second lines facing the first prism sheet and facing the first prism sheet side A second prism sheet having a second prism pattern provided with a prism, and light emitted from the second prism sheet has a luminance in a direction intersecting with a ridgeline of the second linear prism. However, the end portion is higher than the central portion of the second prism sheet.

  In a preferred example, the light source is disposed to face a corner portion of the light guide plate or a central portion of a side on which light from the light source of the light guide plate is incident, and the first prism pattern or the second prism. The pattern is a plurality of grooves formed concentrically around the light source, and of the two inclined surfaces constituting the groove, the inclined surface located on the light source side passes through the light exit surface of the light guide plate. It is preferably an effective inclined surface that collects the emitted light in the normal direction of the light exit surface. Thereby, for example, when the second prism sheet is viewed in a plan view, the luminance and the viewing angle with respect to the short side direction (vertical direction in the front view) of the second prism sheet are suppressed, and the second prism sheet is suppressed. The luminance and viewing angle in the long side direction (front view left-right direction) of the prism sheet can be increased.

  In a preferred example, an electro-optical device including the above-described illumination device and an electro-optical panel disposed on the light output surface side of the second prism sheet can be configured. Therefore, this electro-optical device is used as a vehicle-mounted electro-optical panel such as a navigation system, and the electro-optical device is installed near the dashboard located in the center of the driver's seat and the passenger's seat, and the two directions are set. When set on the driver's seat and passenger's side where passengers are present, the brightness and viewing angle on the windshield side located on the upper side of the dashboard is suppressed without depending on the type of vehicle. The brightness and the viewing angle on the driver's seat side and the passenger seat side can be increased. Therefore, according to the electro-optical device to which the illumination device is applied, it can be suitably used as an in-vehicle electro-optical panel.

  In a preferred example of the illumination device for the electro-optical device, a ridge line of the first linear prism intersects with a ridge line of the second linear prism, and the first linear prism has the ridge line. It is preferable that the intersection angle between the ridge line and the ridge line of the second linear prism is defined as 60 to 90 degrees.

  In another preferable example of the illumination device for the electro-optical device, it is preferable that the ridge line of the first linear prism and the ridge line of the second linear prism are arranged in parallel. In other words, the extending direction of the ridge line of the first linear prism of the first prism sheet and the extending direction of the ridge line of the second linear prism of the second prism sheet are defined in the same direction. Is preferred.

  In another aspect of the illuminating device for an electro-optical device, the vertex angle of the second linear prism is larger than the vertex angle of the first linear prism. In a preferred example, the apex angle of the first linear prism can be defined as 60 degrees to 70 degrees. Thereby, the light emitted through the light exit surface of the light guide plate is refracted by the inclined surface of the first linear prism of the first prism sheet, and the normal direction of the light exit surface and the first and second prism sheets is determined. In addition, the light can be condensed toward the second prism sheet side. Further, the apex angle of the second linear prism can be defined as 80 degrees to 140 degrees, more preferably 80 degrees to 100 degrees.

  Here, if the apex angle of the second linear prism of the second prism sheet is smaller than 80 degrees, the luminance in the normal direction becomes extremely small when the second prism sheet is viewed in plan. It has been experimentally found that the luminance of the second prism sheet in the long-side direction (front view left-right direction) becomes too large. Therefore, in this case, when the electro-optical device using the illumination device is viewed from the front, the luminance in the long side direction (front view left-right direction) is sufficient, but the luminance in the front direction (vertical direction) is It becomes insufficient, and it becomes difficult to use it suitably as a vehicle-mounted electro-optical panel. On the other hand, when the apex angle of the second linear prism of the second prism sheet is larger than 140 °, the luminance in the normal direction becomes too large when the electro-optical device using the illumination device is viewed from the front. At the same time, it has been experimentally found that the luminance of the electro-optical device in the long side direction (right and left direction in the front view) becomes too small. Therefore, in this case, when the electro-optical device using the illumination device is viewed from the front, the luminance in the front direction is sufficient, but the luminance in the long side direction (left-right direction in front view) of the electro-optical device is sufficient. It becomes insufficient, and it becomes difficult to use it suitably as a vehicle-mounted electro-optical panel.

  Therefore, in this aspect, as described above, the apex angle of the second linear prism is preferably set to 80 degrees to 140 degrees, more preferably 80 degrees to 100 degrees. Thereby, the light emitted from the first prism sheet can be refracted by the two inclined surfaces of the second linear prism of the second prism sheet and divided into two directions. Brightness and viewing angle can be increased. Therefore, when the electro-optical device is viewed from the front, it is possible to set the luminance in the long side direction (left-right direction of the front view) and the size of the viewing angle to an appropriate relationship according to the type of vehicle. It becomes.

  In a preferred example, a distance between the adjacent second linear prisms is greater than a distance between the adjacent first linear prisms, and the first linear prisms The vertical distance from the virtual bottom surface to the ridgeline of the first linear prism is larger than the vertical distance from the virtual bottom surface of the second linear prism to the ridgeline of the second linear prism. Yes.

  In another aspect of the present invention, an electro-optical device includes the illumination device described above and an electro-optical panel disposed on the light output surface side of the second prism sheet.

  In another aspect of the invention, an electronic apparatus including the above-described electro-optical device in a display portion can be configured.

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

[First Embodiment]
(Configuration of liquid crystal device including lighting device)
FIG. 1 is a front view showing a schematic configuration of a liquid crystal device 100 to which the illumination device according to the first embodiment of the present invention is applied. FIG. 2 is a cross-sectional view showing a schematic configuration of the liquid crystal device 100 taken along the cutting line AA ′ of FIG. In FIG. 1, the forward direction of the page, that is, the normal direction to the display surface of the liquid crystal device 100 is defined as the Z direction, the right direction of the page is defined as the X direction, and the upward direction of the sheet is defined as the Y direction. 2, the front side of the paper surface is defined as the X direction, the right side of the paper surface is defined as the Y direction, and the upward direction of the paper surface is defined as the Z direction. Further, in FIG. 2, for convenience of explanation, the respective constituent elements are illustrated at intervals, but actually, the liquid crystal device 100 is configured in a state where they are overlapped in the Z direction in the drawing.

  The liquid crystal device 100 includes a reflection sheet 31 having a function of reflecting light, a lighting device 1 disposed above the reflection sheet 31, and a liquid crystal display panel 20 disposed above the lighting device 1. Configured.

  The illuminating device 1 is disposed on the light guide plate 10, the light source portion 15 disposed on one end surface of the light guide plate 10 (corresponding to a light incident end surface 10a described later), the upper side of the light guide plate 10, and has an oblong shape (rectangular shape) A first prism sheet 12 having a planar shape and a second prism sheet 13 disposed on the upper side of the first prism sheet 12 and having a horizontally long (rectangular) planar shape.

  The light guide plate 10 has a horizontally long (rectangular) planar shape and is made of a transparent acrylic resin or the like. The light source unit 15 includes a plurality of LEDs 16 as point light sources. As shown in FIG. 1, the LEDs 16 are arranged at an appropriate interval in one direction that is the X direction.

  Since the first prism sheet 12 is disposed on the upper side of the light guide plate 10, the first prism sheet 12 is positioned between the light guide plate 10 and the second prism sheet 13. The first prism sheet 12 has a role of collecting the light L emitted from the light source unit 15 through the light exit surface 10b of the light guide plate 10 in the Z direction, which is the normal direction. The first prism sheet 12 has a plurality of linear prisms 12x having a triangular cross section. Each linear prism 12x is provided periodically and at regular intervals in one direction which is the Y direction, and the distance between the ridge lines 12a of the adjacent linear prisms 12x is set to d1. Further, the ridge line 12a of each linear prism 12x extends in one direction which is the X direction. For this reason, the extending direction of the ridge line 12a of each linear prism 12x is defined in a direction parallel to the arrangement direction of the LEDs 16 and in the same direction. Note that the apex angle and height of each linear prism 12x of the first prism sheet 12 are set to predetermined sizes, which will be described later.

  The second prism sheet 13 is positioned between the first prism sheet 12 and the liquid crystal display panel 20 by being arranged on the upper side of the first prism sheet 12. The second prism sheet 13 emits light emitted in the Z direction, which is the normal direction, by the linear prisms 12x of the first prism sheet 12 in the ± X direction with respect to the normal direction, that is, the left side in FIG. And has a role of dividing into two directions on the right side of the page (details will be described later). The second prism sheet 13 includes a plurality of linear prisms 13x having a triangular cross section. Each linear prism 13x is provided periodically and at a constant interval in one direction, which is the X direction, and the distance between the ridge lines 13a of the adjacent linear prisms 13x is set to d2 (> d1). . Therefore, the distance d2 between the ridge lines 13a of the adjacent linear prisms 13x is larger than the distance d1 between the ridge lines 12a of the adjacent linear prisms 12x. Further, the ridge line 13a of each linear prism 13x extends in one direction which is the Y direction. Therefore, the ridge line 13a of each linear prism 13x of the second prism sheet 13 and the ridge line 12a of each linear prism 12x of the first prism sheet 12 intersect with each other at an angle of 90 degrees. That is, the intersection angle θ3 between the ridge line 13a of each linear prism 13x of the second prism sheet 13 and the ridge line 12a of each linear prism 12x of the first prism sheet 12 is defined as 90 degrees. Thereby, the extending direction of the ridge line 13 a of each linear prism 13 x of the second prism sheet 13 is defined in a direction orthogonal to the arrangement direction of the LEDs 16. The apex angle and height of each linear prism 13x of the second prism sheet 13 are set to predetermined sizes, which will be described later.

  The liquid crystal display panel 20 is suitably used as a display panel of a single-sided display type mobile phone, and has a display area substantially the same as the light emitting area of the light guide plate 10. The liquid crystal display panel 20 is formed by bonding a pair of first and second substrates 21 and 22 having transparency and insulating properties such as glass and quartz through a frame-shaped sealing material 23 and partitioned by the sealing material 23. A liquid crystal 24 is sealed in the region. In the present invention, the structure of the liquid crystal display panel is not particularly limited.

  In the liquid crystal device 100 having the above configuration, as shown in FIG. 2, the light L emitted from each LED 16 in the light source unit 15 is transmitted through the light guide plate 10, the first prism sheet 12, the second prism sheet 13, and the like. The light is emitted to the outside via the liquid crystal display panel 20. This point will be described in detail with reference to FIG.

  FIG. 3A shows a cross-sectional configuration of the illumination device 1 excluding the second prism sheet 13 in FIG. FIG. 3B is a cross-sectional view when the second prism sheet 13 is cut along the X direction in FIGS. 1 and 2.

  Specifically, the light L1 emitted from each LED 16 enters the light guide plate 10 through the light incident end face 10a of the light guide plate 10 facing the light source unit 15, as shown in FIG. Then, the light L1 incident on the inside of the light guide plate 10 is opposite to the surface 10b of the light guide plate 10 (hereinafter referred to as “light output surface 10b”) located on the first prism sheet 12 side and the light output surface 10b. Propagation is repeated between the light guide plate 10 and the surface 10c of the light guide plate 10 (hereinafter referred to as "reflection surface 10c"), thereby propagating through the light guide plate 10 in the Y direction opposite to the light incident end surface 10a. . The light L1 propagating through the light guide plate 10 passes through the light exit surface 10b and exits toward the first prism sheet 12 when the angle formed with the light exit surface 10b exceeds the critical angle. On the other hand, the light L1 propagating inside the light guide plate 10 is reflected by the reflection sheet 31 when transmitted through the reflection surface 10c with an angle formed with the reflection surface 10c exceeding the critical angle, and returned to the inside of the light guide plate 10 again. It is.

  The light L1 emitted to the first prism sheet 12 side is refracted by the inclined surface 12b of the linear prism 12x and the traveling direction is changed in the Z direction, which is the normal direction, and the light collection having directivity in the normal direction. The emitted light L2 is emitted to the second prism sheet 13 side. Thus, in order to condense light in the Z direction, which is the normal direction, the apex angle θ1 of each linear prism 12x of the first prism sheet 12 is preferably set to 60 degrees to 70 degrees.

  The light L2 emitted to the second prism sheet 13 side is refracted by the two inclined surfaces 13b and 13c of the linear prism 13x. Here, the light L2 emitted to the second prism sheet 13 side is refracted by the inclined surface 13b of the linear prism 13x and passes in the normal direction through the ridge line 13a of the linear prism 13x in FIG. 3B. The light L3 having directivity in the direction of an angle θ4 (hereinafter referred to as “angle (−θ4)” for the sake of convenience) counterclockwise with respect to the existing straight line Z1 is directed toward the liquid crystal display panel 20 shown in FIG. The light exits and is refracted by the inclined surface 13c of the linear prism 13x, and the direction of the angle θ4 clockwise (hereinafter referred to as “angle (+ θ4)” for the sake of convenience) with reference to the straight line Z1 in FIG. Is emitted to the liquid crystal display panel 20 side as light L4 having directivity.

  In a preferred example, the angle θ4 is preferably defined as 30 ° + α (for example, 0 ° ≦ α <60 °), and in order to realize this, the apex of each linear prism 13x of the second prism sheet 13 is set. The angle θ2 is preferably defined as 80 ° to 140 °, more preferably 80 ° to 100 °. Thereby, the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is set larger than the apex angle θ1 of each linear prism 12x of the first prism sheet 12. Therefore, in the linear prism 12x of the first prism sheet 12, the vertical distance d3 from the virtual bottom surface 12s (broken line portion) to the ridge line 12a, and in the linear prism 13x of the second prism sheet 13, The relative relationship with the distance d4 in the vertical direction from the virtual bottom surface 13s (broken line portion) to the ridge line 13a is defined as d3> d4. Further, in the first prism sheet 12, the distance (pitch) between the adjacent linear prisms 12x, in other words, the distance d5 between the ridge lines 12a of the adjacent linear prisms 12x, and the second prism sheet. 13, the relative relationship between the distance (pitch) between the adjacent linear prisms 13x, in other words, the distance d6 between the ridge lines 13a of the adjacent linear prisms 13x is defined as d5 <d6. Yes.

  Lights L3 and L4 refracted by the inclined surfaces 13b and 13c of the linear prisms 13x are emitted to the outside via the liquid crystal display panel 20, respectively. Thereby, the illuminating device 1 can illuminate the liquid crystal display panel 20 from the back surface and perform transmissive display by the liquid crystal device 100.

  Next, a specific operation and effect of the liquid crystal device 100 including the illumination device 1 according to the first embodiment will be described.

  First, since the extending direction of the ridge line 12a of each linear prism 12x of the first prism sheet 12 is defined in the same direction as the arrangement direction of the LEDs 16 in the light source unit 15, the light exit surface 10b of the light guide plate 10 is defined. The light emitted through the first prism sheet 12 can be refracted by the inclined surfaces 12b of the linear prisms 12x of the first prism sheet 12 and emitted to the second prism sheet 13 side. In a preferred example, the apex angle θ1 of each linear prism 12x of the first prism sheet 12 can be defined as 60 degrees to 70 degrees. Thus, the light emitted through the light exit surface 10b of the light guide plate 10 is refracted by the inclined surface 12b of each linear prism 12x of the first prism sheet 12, and the light exit surface 12b, the first prism sheet 12 and the second prism 12 are refracted. The light can be condensed in the normal direction of the prism sheet 13 and toward the second prism sheet 13.

  Further, the extending direction of the ridge line 13a of each linear prism 13x of the second prism sheet 13 is such that the ridge line 13a of the second prism sheet 13 extends when the second prism sheet 13 is viewed in plan view. Since the direction is defined in the short side direction of the second prism sheet 13, that is, the vertical direction (± Y direction in FIG. 1), when the second prism sheet 13 is viewed in plan, The long side direction of the second prism sheet 13, that is, the left-right direction (in FIG. The brightness and viewing angle in the ± X direction) can be increased. In other words, the light emitted from the first prism sheet 12 side is projected in two directions by the two inclined surfaces 13b and 13c of each linear prism 13x of the second prism sheet 13, that is, the long side direction {left and right direction (FIG. 1 ± X directions)}. Therefore, the luminance and the viewing angle with respect to the two directions can be increased.

  This point will be described in detail with reference to FIG. FIG. 4A is a diagram for explaining a method of measuring the luminance of the liquid crystal device 100 according to FIG. The X, Y, and Z directions shown in FIG. 4A correspond to the X, Y, and Z directions shown in FIG. Therefore, the Z direction in FIG. 4A indicates a normal direction with respect to the display surface of the liquid crystal device 100.

  In this measurement method, a luminance measuring device 500 that measures the luminance in the observation direction of the liquid crystal device 100 is provided, and the luminance measuring device 500 is tilted from the Z direction to the ± X direction by an angle θ (0 ° ≦ θ ≦ 90 °). The brightness of the liquid crystal device 100 is measured at the determined position. As a result, as shown in FIG. 4B, in the liquid crystal device 100, a graph showing the relationship between the angle θ corresponding to the ± X direction and the intensity (luminance) is obtained.

  In FIG. 4B, a graph G1 indicated by a solid line corresponds to the ± X direction of the liquid crystal device 100 when the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is set to 120 ° to 130 °. It is a graph which shows the relationship between angle (theta) and intensity | strength (luminance). A graph G2 indicated by a two-dot chain line indicates an angle θ and intensity (luminance) corresponding to the ± X direction of the liquid crystal device 100 when the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is set to 80 °. It is a graph which shows a relationship. In FIG. 4B, the relationship between the angle θ corresponding to the ± X direction and the intensity (luminance) of the liquid crystal device according to the comparative example in which the first prism sheet 12 and the second prism sheet 13 are not provided is also shown. It shows as graph G3 (graph of a dashed-dotted line).

In the case of the liquid crystal device according to the comparative example, as shown in the graph G3, the intensity (luminance) peak occurs in the normal direction, and as the angle θ corresponding to the ± X direction of the liquid crystal device increases. The intensity (brightness) has decreased. Further, the half-value angle of the liquid crystal device according to the comparative example is ± X1. Here, the “half-value angle” refers to an angle corresponding to a half-value luminance of 50% with respect to the peak luminance 100% shown in FIG. Therefore, in the liquid crystal device according to the comparative example, the strength (luminance) in the normal direction is high, but the strength (luminance) decreases as the angle θ corresponding to the ± X direction of the liquid crystal device increases. I understand. For example, in the comparative example, the graph shown in FIG. Here, in FIG. 10A, the vertical axis represents luminance (cd / m ² ), and the horizontal axis in FIG. 10C from the straight line L30 passing through the center of the driver seat side and the passenger seat side, The ± angle (°) in the direction of the straight line L31 passing through the extending direction of the dashboard is shown. In FIG. 10C, the liquid crystal device according to the comparative example is used as an in-vehicle liquid crystal panel such as a navigation system, and the liquid crystal device is in the vicinity of the dashboard 602 positioned in the center between the driver side 600 and the passenger side 601. FIG. 11 is a schematic plan view showing the inside of a vehicle 605 installed in (in a position corresponding to the liquid crystal device 100 in FIG. 10C). Therefore, when the liquid crystal device according to the comparative example is used as an in-vehicle liquid crystal panel such as a navigation system, and the liquid crystal device is installed near the dashboard 602 located in the center of the driver seat side 600 and the passenger seat side 601, Although the luminance in the normal direction of the display surface of the liquid crystal panel is large, there may arise a problem that the strength (luminance) and the viewing angle of the driver's seat side 600 and the passenger seat side 601 where the passenger exists are small.

  On the other hand, in the case of the liquid crystal device 100 in which the magnitude of the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is set to 120 ° to 130 ° (hereinafter referred to as “Example 1” for convenience), a graph As shown in G1, although the intensity (luminance) in the normal direction is lower than that of the liquid crystal device according to the comparative example, the half-value angle (± X2) is larger than the half-value angle (± X1) of the liquid crystal device according to the comparative example. Thus, it can be seen that the intensity (luminance) in two directions at approximately the half-value angle (± X2) is improved. On the other hand, in the case of the liquid crystal device 100 in which the magnitude of the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is set to 80 ° (hereinafter referred to as “Example 2” for convenience), it is shown in a graph G2. As described above, although the intensity (luminance) in the normal direction is lower than that in Example 1, the half-value angle (± X3) is larger than the half-value angle (± X2) of Example 1, and is approximately half-value angle. It can be seen that the intensity (luminance) in two directions at (± X3) is improved.

  From the above measurement results, as the apex angle θ2 of each linear prism 13x of the second prism sheet 13 decreases, the strength (luminance) in the normal direction of the liquid crystal device 100 decreases, while the liquid crystal device 100 It is understood that the intensity (luminance) with respect to the left-right direction (± X direction) is increased.

  Here, when the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is smaller than 80 °, the intensity (luminance) in the normal direction is extremely small when the liquid crystal device 100 is viewed from the front, It has been experimentally found that the intensity (luminance) in the left-right direction (± X direction) becomes too large. Therefore, in this case, when the liquid crystal device 100 is viewed from the front, the strength (brightness) in the left-right direction (± X direction) is sufficient, but the strength (brightness) in the front direction is insufficient, so It becomes difficult to use suitably as a liquid crystal panel. On the other hand, when the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is greater than 140 °, the intensity (luminance) in the normal direction becomes too large when the liquid crystal device 100 is viewed from the front. It has been experimentally found that the intensity (luminance) in the left-right direction (± X direction) becomes too small. Therefore, in this case, when the liquid crystal device 100 is viewed from the front, the luminance in the front direction is sufficient, but the luminance in the left-right direction (± X direction) is insufficient, which is suitable as an in-vehicle liquid crystal panel. It becomes difficult to use it.

  Therefore, in the first embodiment of the present invention, the magnitude of the apex angle θ2 of each linear prism 13x of the second prism sheet 13 is changed within the range of 80 ° to 140 °, more preferably 80 ° to 100 °. As a result, the light emitted from the first prism sheet 12 is refracted by the two inclined surfaces 13b and 13c of the linear prisms 13x of the second prism sheet 13 to be refracted in two directions, that is, left and right of the liquid crystal device 100. It can be divided into directions (± X directions), and the luminance and viewing angle for the two directions can be increased. For example, in the first embodiment, the graph is as shown in FIG. Here, FIG.10 (b) shows an example of the graph which concerns on 1st Embodiment corresponding to Fig.10 (a). Therefore, when the liquid crystal device 100 is viewed from the front, the intensity (luminance) in the left-right direction (± X direction) and the size of the viewing angle can be set in an appropriate relationship according to the type of vehicle. As a result, as shown in FIG. 10C, the liquid crystal device 100 according to the first embodiment is used as an in-vehicle liquid crystal panel such as a navigation system, and the liquid crystal device 100 is installed on the driver seat side 600 and the passenger seat side 601. When installed near the dashboard 602 located in the center and the above two directions are set to the driver side 600 and the passenger side 601 where the passenger is present, the dashboard is not dependent on the type of vehicle. It is possible to increase the brightness and viewing angle of the driver seat side 600 and the passenger seat side 601 while suppressing the brightness and viewing angle size with respect to the windshield side located on the upper side of the board 602. Can be eliminated. Therefore, according to the liquid crystal device 100 to which the illumination device 1 is applied, it can be suitably used as a vehicle-mounted liquid crystal panel.

  Further, the ridge line 12a of each linear prism 12x of the first prism sheet 12 and the ridge line 13a of each linear prism 13x of the second prism sheet 13 intersect each other, and the ridge line 12a of each linear prism 12x and each linear prism The crossing angle θ3 with the 13x ridge line 13a is preferably defined as 60 to 90 degrees. Further, the light emitted from the first prism sheet 12 is preferably higher in luminance in the direction intersecting the ridge line 12a of each linear prism 12x at the end than at the center of the first prism sheet 12. . Further, the light emitted from the second prism sheet 13 preferably has a higher luminance in the direction intersecting the ridge line 13a of each linear prism 13x at the end than at the center of the second prism sheet 13. .

[Second Embodiment]
Next, the configuration and the like of the liquid crystal device 200 to which the illumination device according to the second embodiment of the present invention is applied will be described. In the following, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 5 is a front view corresponding to FIG. 2 and is a front view showing a schematic configuration of a liquid crystal device 200 to which the illumination device 11 according to the second embodiment of the present invention is applied.

  When the first embodiment and the second embodiment are compared, they are mainly different in the relative positional relationship between the light source unit 15 and the second prism sheet 13 with respect to the liquid crystal display panel 20.

  Specifically, when the liquid crystal device 200 is observed from the Z direction, which is the normal direction, the light source unit 15 is disposed on the left end surface 10L side of the light guide plate 10 located on the left side of the sheet. Each LED 16 provided in the light source unit 15 is arranged at an appropriate interval in one direction which is the Y direction. Thereby, the left end surface 10 </ b> L of the light guide plate 10 facing the light source unit 15 is a light incident end surface for guiding the light L emitted from each LED 16 into the light guide plate 10.

  The extending direction of the ridge line 12a of each linear prism 12x of the first prism sheet 12 is defined in the same direction as the arrangement direction of the LEDs 16 and in a parallel direction. On the other hand, the extending direction of the ridge line 13a of each linear prism 13x of the second prism sheet 13 is the same as that of the first embodiment, and the extending direction of the ridge line 12a of each linear prism 12x of the first prism sheet 12; And it is prescribed | regulated in the direction parallel to the arrangement direction of each LED16, respectively. Thereby, the crossing angle between the ridge line 12a of each linear prism 12x of the first prism sheet 12 and the ridge line 13a of each linear prism 13x of the second prism sheet 13 is defined as 0 °. In other words, the extending direction of the ridge line 12a of each linear prism 12x of the first prism sheet 12 and the extending direction of the ridge line 13a of each linear prism 13x of the second prism sheet 13 are defined in the same direction. . Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  In 2nd Embodiment which has the above structure, since the extension direction of the ridgeline 12a of each linear prism 12x of the 1st prism sheet 12 is prescribed | regulated in the same direction as the arrangement direction of each LED16, it radiate | emits from each LED16. The transmitted light L propagates through the inside of the light guide plate 10 according to the same principle as that of the first embodiment described above, and further exits to the first prism sheet 12 side through the light output surface 10a of the light guide plate 10, The emitted light L is refracted by the inclined surface 12b (see FIG. 2) of each linear prism 12x of the first prism sheet 12, and is condensed toward the front side of the sheet, that is, in the Z direction, which is the normal direction. Light exits to the sheet 13 side. As shown in FIG. 2, the light L emitted to the second prism sheet 13 side is refracted by the inclined surfaces 13b and 13c of each linear prism 13x as shown in FIG. Is emitted as light L3 and L4 having directivity in the direction of the angle (± θ4) to the liquid crystal display panel 20 side.

  Therefore, the second embodiment can obtain the same effects as those of the first embodiment, and can be suitably used as an in-vehicle liquid crystal panel.

  In the second embodiment, the light source unit 15 is arranged on the left end surface 10L side of the light guide plate 10 located on the left side of the paper. However, the present invention is not limited to this, and in the present invention, a one-dot chain line in the figure. As shown, the light source unit 15 may be arranged on the right end surface 10R side of the light guide plate 10 located on the right side of the sheet. Even in this case, the same effects as those of the second embodiment described above can be obtained.

[Third embodiment]
Next, the configuration and the like of the liquid crystal device 300 to which the illumination device according to the third embodiment of the present invention is applied will be described. In the following, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 6 is a front view corresponding to FIG. 2, and is a front view showing a schematic configuration of a liquid crystal device 300 to which the illumination device 111 according to the third embodiment of the present invention is applied.

  When the first embodiment and the third embodiment are compared, they are mainly the number of LEDs 16 set, the relative position of the light source unit 15 including the LEDs 16 with respect to the liquid crystal display panel 20, and the first prism sheet. The 12 prism patterns are different.

  Specifically, when the liquid crystal device 300 is observed from the Z direction, which is the normal direction, the light source unit 15 is disposed on the right end surface 10R side of the light guide plate 10 located on the right side of the sheet. In the present invention, the light source unit 15 may be disposed to face the central part of the side on which light from the light source unit 15 of the light guide plate 10 is incident. One corner of the right end surface 10R of the light guide plate 10 positioned on the light source unit 15 side is chamfered so as to be substantially orthogonal to a straight line (diagonal line) connecting the corner and the corner positioned diagonally. A chamfered surface 10Ra is formed. And one LED16 is arrange | positioned in the position facing the chamfering surface 10Ra. The bottom surface of the first prism sheet 12 (the lower surface in FIG. 6) has a prism pattern that emits the light emitted through the light output surface 10b of the light guide plate 10 to the second prism sheet 13 side. The prism pattern has a plurality of arc-shaped grooves 12p. Specifically, the first prism sheet 12 is formed with a plurality of arc-shaped grooves 12p concentrically around the position of the LED 16 as a prism pattern. For this reason, the arc-shaped grooves 12p of the first prism sheet 12 and the LEDs 16 are in a relatively substantially positional relationship. Of the two inclined surfaces (not shown) constituting each groove 12p of the first prism sheet 12, the inclined surface on the LED 16 side emits light emitted from the LED 16 through the light guide plate 10 to the second prism sheet 13. It is an effective inclined surface that reflects and converges toward the Z direction, which is the normal direction. The configuration of the second prism sheet 13 is the same as that of the first embodiment. Therefore, in this illumination device 111, only one LED 16 is turned on, and the liquid crystal display panel 20 is illuminated only with light emitted from the LED 16.

  In the third embodiment having the above configuration, the light L emitted from one LED 16 enters the light guide plate 10 through the chamfered surface 10Ra of the light guide plate 10. The light L incident on the inside of the light guide plate 10 propagates in the light guide plate 10 in a direction intersecting with each groove 12p and in a direction opposite to the chamfered surface 10Ra. Is emitted toward the first prism sheet 12 through a light exit surface located on the opposite side to the bottom surface of the first prism sheet 12. The light emitted to the first prism sheet 12 side is reflected by the inclined surface located on the LED 16 side out of the two inclined surfaces constituting each groove 12p of the first prism sheet 12, and further Z in the normal direction. The light is condensed in the direction and emitted to the second prism sheet 13 side. The light L emitted to the second prism sheet 13 side is refracted by the inclined surfaces 13b and 13c of the respective linear prisms 13x as shown in FIG. With reference to Z1, the light L3 and L4 having directivity in the direction of the angle (± θ4) is emitted to the liquid crystal display panel 20 side.

  Therefore, the third embodiment can obtain the same operational effects as the first embodiment, and can be suitably used as an in-vehicle liquid crystal panel.

[Modification]
In the present invention, in the first embodiment, the extending direction of the ridge line 12a of the linear prism 12x of the first prism sheet 12 and the linear shape of the second prism sheet 13 with respect to the arrangement direction of the LEDs 16 are described. You may prescribe | regulate the extension direction of the ridgeline 13a of the prism 13x in the reverse relationship to the structure of 1st Embodiment. Hereinafter, with respect to such a configuration, only differences from the first embodiment will be described with reference to FIGS. 7 to 9. In the following, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 7 is a front view showing a schematic configuration of a liquid crystal device 400 to which the illumination device according to the modification is applied, corresponding to FIG. FIG. 8 is a cross-sectional view illustrating a schematic configuration of the liquid crystal device 400 taken along a cutting line B-B ′ in FIG. 7. FIG. 9A is a plan view schematically illustrating main elements of the liquid crystal device 400 corresponding to FIG. 7, for explaining the function of the first prism sheet 12. FIG. 9B is a side view schematically showing main elements of the liquid crystal device 400 corresponding to FIG. FIG. 9C is a plan view schematically illustrating main elements of the liquid crystal device 400 corresponding to FIG. 7, for explaining the function of the second prism sheet 13. FIG. 9D is a side view schematically showing main elements of the liquid crystal device 400 corresponding to FIG.

  That is, when the modification described below is compared with the first embodiment described above, both of them extend the ridgelines of the linear prisms of the first prism sheet 12 and the second prism sheet 13. Only the direction is different, and the configuration of the modified example is the same as that of the first embodiment with respect to other points.

  The first prism sheet 12 has a plurality of linear prisms 12x having a triangular cross-section, and each linear prism 12x is provided periodically and at regular intervals in one direction, which is the X direction, and adjacent lines. The distance between the ridge lines 12a of the prisms 12x is set to d1. Further, the ridge line 12a of each linear prism 12x extends in one direction which is the Y direction. For this reason, the extending direction of the ridge line 12a of each linear prism 12x is defined in a direction orthogonal to the arrangement direction of the LEDs 16. Note that the apex angle and height of each linear prism 12x of the first prism sheet 12 are set to the same size as in the first embodiment.

  On the other hand, the second prism sheet 13 includes a plurality of linear prisms 13x having a triangular cross section, and each linear prism 13x is provided periodically and at a constant interval in one direction that is the Y direction. The distance between the ridge lines 13a of the linear prisms 13x to be set is set to d2 (> d1). Further, the ridge line 13a of each linear prism 13x extends in one direction which is the X direction. Therefore, the ridge line 13a of each linear prism 13x of the second prism sheet 13 and the ridge line 12a of each linear prism 12x of the first prism sheet 12 intersect with each other at an angle of 90 degrees. Thereby, the extending direction of the ridge line 13a of each linear prism 13x of the second prism sheet 13 is defined in a direction parallel to the arrangement direction of the LEDs 16. The apex angle and height of each linear prism 13x of the second prism sheet 13 are set to the same size as in the first embodiment.

  In the illuminating device having the above configuration, the first prism sheet 12 emits the light emitted from the light source unit 15 through the light exit surface 10b of the light guide plate 10 as shown in FIGS. 9 (a) and 9 (b). Using the normal direction (Z direction) as a reference, it has a role to divide into two directions, that is, the ± X direction, that is, the upper side and the lower side as shown by the arrows in FIG. For this reason, the light emitted from the light exit surface 10b of the light guide plate 10 passes through the first prism sheet 12 and is specifically shown in FIG. 9B by each linear prism 12x of the first prism sheet 12. Thus, the light is distributed in the directions of L5 and L6. On the other hand, as shown in FIGS. 9C and 9D, the second prism sheet 13 stands the light L5 and L6 emitted through the first prism sheet 12 in the normal direction (Z direction). Has a function to raise. For this reason, the lights L5 and L6 emitted from the first prism sheet 12 pass through the second prism sheet 13 and are thereby transmitted by the linear prisms 13x of the second prism sheet 13 as shown in FIG. As shown in (d), the lights L5 and L6 rise as light L7 in the normal direction. Thereby, this modification can obtain substantially the same operation effect as the first embodiment described above.

  Further, the second prism sheet 13 is formed in a horizontally long shape and a rectangular shape having a short side and a long side. However, in the present invention, the shape of the second prism sheet 13 is not limited and deviates from the purpose. For example, the second prism sheet 13 may be formed in a square shape or a vertically long shape and a rectangular shape having a short side and a long side.

[Electronics]
Next, specific examples of electronic devices to which the liquid crystal devices 100, 200, and 300 according to the first to third embodiments of the present invention can be applied will be described with reference to FIG.

  First, an example in which the liquid crystal devices 100, 200, and 300 according to the first to third embodiments of the present invention are applied to a display unit of a portable personal computer (so-called laptop computer) will be described. FIG. 11A is a perspective view showing the configuration of this personal computer. As shown in the figure, a personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal devices 100, 200, and 300 according to the present invention are applied as a panel.

  Next, an example in which the liquid crystal devices 100, 200, and 300 according to the first to third embodiments of the present invention are applied to a display unit of a mobile phone will be described. FIG. 11B is a perspective view showing the configuration of this mobile phone. As shown in the figure, the mobile phone 720 includes the liquid crystal devices 100, 200, and 300 according to the first to third embodiments of the present invention, together with a plurality of operation buttons 721, an earpiece 722, and a mouthpiece 723. An applied display unit 724 is provided.

  Note that examples of electronic devices to which the liquid crystal devices 100, 200, and 300 according to the first to third embodiments of the present invention can be applied include the personal computer shown in FIG. 11A and the portable device shown in FIG. In addition to telephones, LCD TVs, viewfinder type / monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, digital still cameras, etc. .

The top view which shows schematic structure of the liquid crystal device containing the illuminating device which concerns on 1st Embodiment. FIG. 2 is a cross-sectional view of a liquid crystal device including an illumination device along a cutting line A-A ′ in FIG. 1. The figure explaining the control method of the light by the 1st and 2nd prism sheet. The graph which shows the angle of the left-right direction of a liquid crystal device, and the relationship of a luminance. The top view which shows schematic structure of the liquid crystal device containing the illuminating device which concerns on 2nd Embodiment. The top view which shows schematic structure of the liquid crystal device containing the illuminating device which concerns on 3rd Embodiment. The top view which shows schematic structure of the liquid crystal device containing the illuminating device which concerns on a modification. FIG. 8 is a cross-sectional view of a liquid crystal device including an illumination device along a cutting line B-B ′ in FIG. 7. The figure explaining the control method of the light by the 1st and 2nd prism sheet of a modification. The graph which shows an example of the relationship between the angle of the left-right direction of the liquid crystal device which concerns on a comparative example, and 1st Embodiment, and a brightness | luminance. FIG. 14 is a perspective view of an electronic device to which a liquid crystal device including the lighting device of the invention is applied.

Explanation of symbols

  1, 11, 111 Illumination device, 10 Light guide plate, 12 First prism sheet, 12x, 13x Linear prism, 12a, 13a Ridge line, 12b, 13b, 13c Inclined surface, 12s, 13s Virtual bottom surface, 12p Groove, 15 Light source Part, 16 LED, 20 liquid crystal display panel, 100, 200, 300, 400 liquid crystal device

Claims (12)

A light source;
A light guide plate having a light exit surface for emitting light emitted from the light source;
A first prism sheet having a first prism pattern comprising a plurality of first linear prisms facing the light guide plate and facing the light guide plate side;
A second prism sheet having a second prism pattern that is opposed to the first prism sheet and includes a plurality of second linear prisms facing the first prism sheet side ,
The light emitted from the first prism sheet has a higher luminance in the direction intersecting the ridge line of the first linear prism at the end than at the center of the first prism sheet. A lighting device.   A light source;
  A light guide plate having a light exit surface for emitting light emitted from the light source;
  A first prism sheet having a first prism pattern comprising a plurality of first linear prisms facing the light guide plate and facing the light guide plate side;
  A second prism sheet having a second prism pattern that is opposed to the first prism sheet and includes a plurality of second linear prisms facing the first prism sheet side,
  The light emitted from the second prism sheet has higher brightness in the direction intersecting the ridgeline of the second linear prism at the end than at the center of the second prism sheet. A lighting device. The light source is disposed to face a corner portion of the light guide plate or a central portion of a side where light from the light source of the light guide plate is incident,
The first prism pattern or the second prism pattern is a plurality of grooves formed concentrically around the light source,
Of the two inclined surfaces constituting the groove, the inclined surface located on the light source side is an effective inclined surface that condenses the light emitted through the light exit surface of the light guide plate in the normal direction of the light exit surface. the lighting device according to claim 1 or 2, characterized in that. The ridge line of the first linear prism and the ridge line of the second linear prism intersect,
3. The illumination according to claim 1, wherein an intersection angle between the ridge line of the first linear prism and the ridge line of the second linear prism is defined as 60 degrees to 90 degrees. apparatus. The lighting device according to claim 1 or 2, characterized in that the edge line of said first ridge line of the linear prisms second linear prisms are arranged so as to parallel. The size of the apex angle of the second linear prism, the illumination device according to claim 1 or 2, characterized in that greater than the top angle of the first linear prisms. The apex angle of the first linear prism is defined as 60 degrees to 70 degrees, and the apex angle of the second linear prism is defined as 80 degrees to 140 degrees. The lighting device according to claim 6 . 3. The lighting device according to claim 1, wherein a distance between the adjacent second linear prisms is greater than a distance between the adjacent first linear prisms. The vertical distance from the virtual bottom surface of the first linear prism to the ridgeline of the first linear prism is the distance from the virtual bottom surface of the second linear prism to the ridgeline of the second linear prism. the lighting device according to claim 1 or 2, characterized in that greater than a distance in the vertical direction. The light source has a plurality of point light sources,
Arrangement direction of the plurality of point light sources, the lighting device according to claim 1 or 2, characterized in that it is defined in the extending direction and the same direction of the ridge of the first linear prisms. The lighting device according to any one of claims 1 to 10 ,
An electro-optical device, comprising: an electro-optical panel disposed on a side facing the second prism sheet. An electronic apparatus comprising the electro-optical device according to claim 11 as a display unit.

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