JP2014219463A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device performing a variety of high quality displays and reducing a power consumption of a lighting device.SOLUTION: The liquid crystal display device comprises: a normally black liquid crystal display element having a plurality of display parts including first and second display parts, the display parts displayed in different colours; a lighting device including first and second light sources 20X, 20Y, and a light guide plate 21 to which light emitted from the first and second light sources is introduced, and emitting illumination light to the liquid crystal display element; and a circuit driving the liquid crystal display element and causing the first and second light sources to emit light. The first and second light sources respectively emit first and second light travelling in the light guide plate in first and second directions. The light guide plate includes: a first light-emitting region 21X reflecting the first light, and emitting the light from an emission surface to the first display part; and a second light-emitting region 21Y reflecting the second light, and emitting the light from the emission surface to the second display part. The first light-emitting region extends in the second direction and includes a recess and a protrusion reflecting the first light while the second light-emitting region extends in the first direction and includes a recess and a protrusion reflecting the second light.

Description

  The present invention relates to a liquid crystal display device in which at least one segment display unit is displayed in a different color from other segment display units.

  As a display device having a display unit with numbers, character shapes, 7 segments, etc. and performing segment display, a self-luminous display device using a fluorescent display tube or an organic LED, or a back surface of a liquid crystal display element which is a non-light emitting device is inorganic or A liquid crystal display device having a configuration in which a backlight unit (BLU) having a light source such as an organic LED is disposed is known.

  The self-luminous display device has a large brightness difference between the display unit and the background unit (non-display unit) (contrast ratio is extremely high), excellent viewing angle characteristics, the display unit is bright display, and the background unit is dark display. Excellent display performance as a display mode.

  However, in a self-luminous display device that is driven by current, for example, when the display area of one segment is large, the drive current increases and the display uniformity deteriorates with time, resulting in uneven brightness (display unevenness). There is a phenomenon in which the display brightness itself decreases. In addition, for example, when the area difference between a plurality of segment display units is large, the difference in drive current supplied to each segment increases, and the burden on the drive device increases. May cause uneven brightness. Furthermore, it is considered that luminance unevenness due to the length of the accumulated light emission time of each segment display unit due to the display state of the display unit also occurs. In addition, since the circuit is based on current driving, the circuit configuration of the driving device is complicated.

  On the other hand, since the liquid crystal display device is voltage-driven, for example, even if the area of the one-segment display section is large, luminance unevenness does not occur, and even if the area difference between the plurality of segment display sections is large, uniform display is possible. The state can be maintained for a long time. Further, in the liquid crystal display device, since the operation of dynamically changing the luminance of the light source according to the change of the display state is not performed, the emission luminance of the light source (for example, one or a plurality of LEDs) of the BLU is substantially constant. is there. Long life due to small change in brightness.

  In recent years, normally black liquid crystal display devices that realize a good dark state when no voltage is applied have been widely used. In the normally black type liquid crystal display device, the vertical alignment mode or the in-plane switching mode is used as the operation mode, and the luminance of the background portion is remarkably low, for example, the same level as that of a polarizing plate arranged in a crossed Nicol arrangement. Further, it is possible to improve the viewing angle characteristics of the background portion with simple viewing angle compensation.

  The BLU is disposed, for example, on the back surface of the effective display portion of the liquid crystal display element, and illuminates the entire surface of the effective display portion or a partial area. By illuminating only a part of the area, the power consumption of the light source can be reduced.

  The sidelight type lighting device described in Patent Document 1 includes a plurality of rectangular parallelepiped light guides arranged in a strip shape through an air gap, and an LED light source is disposed on a side surface of each light guide. The A lens diffusion sheet that equalizes the intensity of the emitted light is provided on the exit side of the illumination device. Patent Document 1 also discloses an invention of a lighting device having a direct structure. The direct type illumination device has a bathtub structure in which a plurality of illumination areas separated by white partitions are arranged in a strip shape, an LED light source on the bottom surface of the bathtub, and a lens on the top surface (light emission side) of the bathtub A diffusion sheet is placed. The lighting device described in Patent Literature 1 can perform lighting control of the light source independently for each of the regions divided into strips, and can light the BLU only in a region corresponding to a part of the effective display unit.

  In the lamp described in Patent Document 2, for example, light sources that emit light of different colors are arranged in the vicinity of each apex angle of the substantially rectangular light guide member. The light emitted from the light source and introduced into the light guide member is reflected by the reflecting surface (light emitting unit) and emitted from the light guide member. Each reflecting surface is formed so as to reflect only incident light from a specific light source. The lamp described in Patent Document 2 can emit light from a partial region of the light guide member, and according to the lamp described in Patent Document 2, for example, from each light emitting unit without mixing the colors of the respective light sources. Light of a desired color can be emitted.

  Patent Document 3 discloses an invention of a decorative panel that can display various patterns with a simple structure. The decorative panel employs a sidelight-type backlight structure, and unevenness (line pattern) that reflects light is formed for each region. A part of the light traveling in the direction crossing the longitudinal direction of the line is reflected by the unevenness, whereby color control for each region is performed.

  Patent Document 4 describes an illumination unit used for a gaming machine, for example. The illumination unit includes a concavo-convex cut row extending in a direction crossing each other. The light reflected by the concavo-convex cut row enters the player's eyes, so that moire occurs and the visual effect is enhanced.

  In a display device that performs segment display, when an effective display portion is divided into a plurality of regions and the lighting color is controlled for each region, in a self-luminous display device, one type of phosphor or light emission is included in one segment display portion. Since only layers can be arranged, only monochrome display can be realized. The same applies to a method using a color filter.

  On the other hand, in the case of a liquid crystal display device, the emission color of each region can be controlled to a plurality of colors by using the region division BLU. For example, since the color of the display unit can be changed by a specific region depending on the temperature around the device, the amount of information in the one-segment display unit can be increased. Therefore, information display can be performed with a small number of segments.

  Further, in a liquid crystal display device including a liquid crystal display element capable of realizing an electro-optic response at high speed, a multi-color BLU that uniformly lights an effective display unit, and a circuit that operates the liquid crystal display element and the multi-color BLU synchronously Field sequential drive that performs time-resolved display of colors by switching the lighting color of the BLU at a speed faster than the response speed of the human eye and simultaneously switching the light and dark states of the liquid crystal display element so that a desired display color can be obtained By performing the above, multicolor display can be realized. A liquid crystal display device that performs field sequential driving has an advantage that the structure of the BLU can be simplified because multi-color display can be realized for each segment display unit, and the BLU need not be divided into regions.

JP 2000-275605 A JP 2006-259263 A JP 2009-297554 A JP 2011-240029 A

  In the segment display type liquid crystal display device, the area of the display portion in the effective display portion is about 50% or less, which is very small as compared with the dot matrix type liquid crystal display device. When the entire surface of the effective display portion is illuminated with BLU, the background portion that does not affect the display is also illuminated. Therefore, the light use efficiency of the BLU is low, and the power consumption is higher than that of a self-luminous display device that operates only with the display portion. This is disadvantageous.

  Further, even in a high contrast normally black liquid crystal display device using a vertical alignment mode or an in-plane switching mode, the transmittance of the background portion when viewed from the front is 0.005% or more. In comparison, the contrast ratio is low.

  Further, when the effective display section is divided into a plurality of areas and different colors are displayed in each area, the area division BLU limits the shape of the area to be divided and increases the number of parts as the number of area divisions increases. There is a concern that the cost will rise. In addition, the alignment accuracy with the display pattern of the liquid crystal display element may not be maintained.

  In the case of a field sequential drive liquid crystal display device that does not use a region-divided BLU, a high-speed electro-optical response of the liquid crystal display element is essential, and thus operation in a low temperature environment is difficult. In addition, since the light utilization efficiency of the BLU is very low, there is a concern that the power consumption by the BLU will increase significantly.

  An object of the present invention is to provide a liquid crystal display device capable of various and high-quality displays.

  Another object of the present invention is to provide a liquid crystal display device in which power consumption by the lighting device is reduced.

  According to one aspect of the present invention, a plurality of segment display units including a first segment display unit and a second segment display unit are provided, and at least one segment display unit is displayed in a color different from other segment display units. A normally black liquid crystal display element, a first light source, a second light source, and a light guide plate into which light emitted from the first and second light sources is introduced, the liquid crystal display element An illumination device that emits illumination light; and a circuit that drives the liquid crystal display element and causes the first and second light sources to emit light, wherein the first light source is parallel to the first direction. The second light source emits first light traveling in the light guide plate with the direction as the optical axis direction, and the second light source has the direction parallel to the second direction orthogonal to the first direction as the optical axis direction. The second light traveling in the light guide plate is emitted, and the light guide plate is A first light-emitting region that reflects the first light with a higher reflectance than the second light-emitting region and emits the light from an emission surface to the first segment display unit; A second light emitting region that reflects the second light with a higher reflectance than the first light emitting region and emits the second light from the emitting surface to the second segment display unit, and the first light emitting region includes: , Extending in a direction parallel to the second direction, and provided with a recess or / and a protrusion for reflecting the first light, wherein the second light emitting region is in a direction parallel to the first direction. A liquid crystal display device is provided that includes a concave portion and / or a convex portion that extends and reflects the second light.

  According to the present invention, it is possible to provide a liquid crystal display device capable of various and high-quality displays.

  In addition, a liquid crystal display device in which power consumption by the lighting device is reduced can be provided.

FIG. 1 is a schematic cross-sectional view of a liquid crystal display device according to an embodiment. FIG. 2 is a schematic perspective view of the liquid crystal display element. 3A to 3E are schematic diagrams illustrating the configurations of the light source 20 and the light guide plate 21. 4A to 4C are schematic diagrams illustrating modified examples of the configuration of the light source 20. 5A to 5C are schematic diagrams illustrating other examples of the configuration of the light source 20 and the light guide plate 21. 6A to 6F are schematic views illustrating other configuration examples of the light guide plate 21. 7A to 7C are schematic views illustrating other configuration examples of the light guide plate 21. FIG. 8 is a schematic plan view showing the effective display unit 50 of the liquid crystal display device according to the embodiment. 9A to 9C are schematic views showing the light guide plate 21 of the liquid crystal display device according to the first embodiment. FIG. 10 is a schematic view showing the light guide plate 21 of the liquid crystal display device according to the second embodiment. 11A and 11B are schematic views showing the light guide plate 21 of the liquid crystal display device according to the third embodiment.

  FIG. 1 is a schematic cross-sectional view of a liquid crystal display device according to an embodiment. The liquid crystal display device according to the embodiment includes a liquid crystal display element, a lighting device (BLU), and a circuit. The circuit is electrically connected to the liquid crystal display element and the BLU.

  The liquid crystal display element includes a front side substrate (common substrate) 10a, a back side substrate (segment substrate) 10b, a liquid crystal layer 16, viewing angle compensation plates 14a and 14b, and polarizing plates 15a and 15b.

  The front-side substrate 10a and the back-side substrate 10b are spaced apart and arranged substantially parallel to each other. The front substrate 10a includes a front transparent substrate 11a, a front transparent electrode (common electrode) 12a formed on the front transparent substrate 11a, and a front alignment film 13a formed on the front transparent electrode 12a. , A back side transparent substrate 11b, a back side transparent electrode (segment electrode) 12b formed on the back side transparent substrate 11b, and a back side alignment film 13b formed on the back side transparent electrode 12b. The front side transparent electrode 12a and the back side transparent electrode 12b are opposed to each other to form a plurality of display units. Each display unit can independently switch between the light and dark display states according to the application mode of the voltage applied between the electrodes 12a and 12b.

  An external extraction electrode terminal portion 17 is disposed in a region of the back side substrate 10b that protrudes from the front side substrate 10a. The electrodes 12 a and 12 b are electrically connected to a circuit outside the liquid crystal display element via the external extraction electrode terminal portion 17.

  The liquid crystal layer 16 is disposed between the alignment film 13a of the front substrate 10a and the alignment film 13b of the back substrate 10b. The liquid crystal layer 16 is a vertical alignment liquid crystal layer in which liquid crystal molecules are aligned vertically or substantially perpendicular to the surfaces of the substrates 10a and 10b.

  A front-side viewing angle compensation plate 14a and a front-side polarizing plate 15a are arranged in this order on the surface opposite to the liquid crystal layer 16 of the front-side substrate 10a. Further, on the surface opposite to the liquid crystal layer 16 of the back side substrate 10b, a back side viewing angle compensation plate 14b and a back side polarizing plate 15b are arranged in this order. The polarizing plates 15a and 15b are arranged in crossed Nicols.

  The BLU includes a light source 20, a light guide plate 21, a reflection plate or light absorption plate 22, and a diffusion plate 23, and is arranged on the back side of the liquid crystal display element.

  The light source 20 includes, for example, an inorganic LED as a light emitting source, and is disposed on the side of the light guide plate 21. The light guide plate 21 is made of, for example, acrylic resin (refractive index: about 1.48). You may form with resin materials, such as a cyclic olefin polymer and a polycarbonate. The light emitted from the light source 20 travels through the light guide plate 21, passes through the diffusion plate 23 that equalizes the intensity of the emitted light, and enters the liquid crystal display element. On the back side of the light guide plate 21, a reflection plate or a light absorption plate 22 is disposed as necessary. The reflection plate 22 reflects a part of the light emitted to the back surface side of the light guide plate 21 and emits it from the front surface side (the diffusion plate 23 side) of the light guide plate 21, and the light absorption plate 22 is the back surface side of the light guide plate 21. Absorbs the light emitted to.

  The circuit board 32 is disposed on the back side of the BLU, for example, and includes a drive circuit that drives the liquid crystal display element, a control circuit that controls light emission of the BLU (light source 20), and the like. The external extraction electrode terminal portion 17 of the liquid crystal display element is connected to the lead frame 31 by, for example, silver paste, and the electrodes 12a and 12b are connected to the drive circuit of the circuit board 32 through the lead frame 31. The light source 20 of the BLU is connected to the control circuit of the circuit board 32.

  The liquid crystal display element, the BLU, and the circuit board 32 are fixed at predetermined positions in a housing (housing) 40.

  FIG. 2 is a schematic perspective view of the liquid crystal display element. In this figure, the alignment process direction (rubbing direction) is indicated by arrows attached to the substrates 10a and 10b (alignment films 13a and 13b). Moreover, the slow axis direction is represented by an arrow attached to the viewing angle compensation plates 14a and 14b, and the absorption axis direction is represented by an arrow attached to the polarizing plates 15a and 15b. The substrates 10a and 10b are subjected to an alignment process in antiparallel. The absorption axis directions of the polarizing plates 15a and 15b are orthogonal to each other, and the absorption axis directions of the polarizing plates 15a and 15b and the slow axis directions of the viewing angle compensation plates 14a and 14b arranged adjacent to each other are orthogonal to each other. . The polarizing plates 15 a and 15 b are arranged so that the respective absorption axis directions are 45 ° with respect to the orientation direction of the liquid crystal layer 16 center molecule (liquid crystal molecule located in the center of the liquid crystal layer 16 in the thickness direction).

  When a polarizing plate is bonded to an actual liquid crystal display element, it is difficult to make the angle formed by the absorption axis directions of the front and back polarizing plates to be 90 ° very accurately. Bonding can be realized within 90 ° ± 2 °. In this application, regarding crossed Nicols, including a range within 90 ° ± 2 °, it is expressed as “90 °”. In addition, it is actually difficult to completely set the angle formed by the absorption axis direction of the polarizing plate and the orientation direction of the center molecule of the liquid crystal layer to 45 °. In the present application, a range within 45 ° ± 2 ° is included. “45 °”.

  In the embodiment, the single-domain vertical alignment type liquid crystal display element in which the substrates 10a and 10b are arranged so that the alignment processing of the substrates 10a and 10b is performed in one direction and the alignment processing direction is anti-parallel is described. An alignment type liquid crystal display element may be used. As an example of a multi-domain vertical alignment type liquid crystal display element, Japanese Patent No. 4107978 discloses that rectangular openings are formed regularly on the front and back electrodes in the display section along the short direction of the opening. The structure formed in this way is shown. When a voltage is applied between the front and back electrodes, an oblique electric field is generated around the opening, and the liquid crystal molecules in the liquid crystal layer are aligned in a plurality of directions.

  Further, instead of the vertical alignment mode, an in-plane switching mode that realizes bright and dark display by rotating liquid crystal molecules in the liquid crystal layer in the substrate plane by applying a voltage may be employed. Any operation mode may be used as long as it is a normally black liquid crystal display element having a low transmittance in the background portion and capable of realizing a high-quality display with high contrast.

  The configuration of the light source 20 and the light guide plate 21 will be described with reference to FIGS. 3A to 3E. As shown in the figure, an XYZ orthogonal coordinate system is defined. The XY direction is the in-plane direction of the light guide plate 21 (BLU illumination in-plane direction), and the Z direction is the normal direction of the light guide plate 21 (BLU normal direction).

Refer to FIG. 3A. The light source 20 includes, for example, a light source 20X disposed on the X-axis negative direction side of the rectangular light guide plate 21 whose sides extend along the X-axis direction and the Y-axis direction, and a light source 20Y disposed on the Y-axis positive direction side. Each of the light sources 20X and 20Y includes one or a plurality of LEDs 20X _a and 20Y _a , and emits light of different colors. The optical axis of light emitted from the light source 20X is parallel to the X-axis direction, and the optical axis of light emitted from the light source 20Y is parallel to the Y-axis direction. In the example shown in the figure, light traveling in the positive direction of the X axis is introduced from the light source 20X into the light guide plate 21, and light traveling in the negative direction of the Y axis is introduced from the light source 20Y into the light guide plate 21. . The control circuit of the circuit board 32 (see FIG. 1) controls the light emission of the light source 20X (LED 20X _a ) and the light source 20Y (LED 20Y _a ).

  In the plane of the light guide plate 21, light emitting areas 21X and 21Y are defined. The light emitting area 21X reflects the light emitted from the light source 20X with a higher reflectance than the light emitting area 21Y and emits the light toward the liquid crystal display element. The light emitting area 21Y reflects the light emitted from the light source 20Y with a higher reflectance than the light emitting area 21X and emits the light toward the liquid crystal display element. For example, in the light emitting region 21X, part of the light emitted from the light source 20X is reflected and the light emitted from the light source 20Y is transmitted. In the light emitting region 21Y, part of the light emitted from the light source 20Y is reflected, and the light emitted from the light source 20X is transmitted. Specifically, the light emitted from the light source 20X goes straight without being deflected in the region 21Y, and the light emitted from the light source 20Y goes straight without being deflected in the region 21X.

FIG. 3B is a cross-sectional view of the light emitting region 21X. This figure shows a cross section along line 3B-3B in FIG. 3A. In the light emitting region 21 </ b> _X , a plurality of grooves (concave portions) 21 </ b> DX are continuously arranged in the X-axis direction on the back surface of the light guide plate 21 so as to form a saw-tooth shaped cross section. The cross section of each groove 21D _X along the X-axis direction is a right-angled isosceles triangle having a base angle of 90 ° on the X-axis positive direction side. The groove 21D _X extends in the Y-axis direction and is formed in a strip shape when viewed from the Z-axis direction. The pitch along the X-axis direction of the grooves 21D _X is preferably 0.005 mm or more and 0.3 mm or less. The depth of the groove 21D _X is desirably 30% or less than 0.01% of the thickness of the light guide plate 21.

FIG. 3C shows a traveling mode of light emitted from the light source 20X. Light travels in the X-axis positive direction, is incident on the inclined surface of the groove 21D _X of the light emitting region 21X. The inclined surface reflects a part of incident light in the positive direction of the Z axis due to the difference in refractive index between the light guide plate 21 (resin) and air, and the reflected light is emitted toward the liquid crystal display element. The light emitted from the light source 20X travels almost straight in the region 21Y and is not emitted in the Z-axis direction.

FIG. 3D is a cross-sectional view of the light emitting region 21Y. This figure shows a cross section taken along line 3D-3D in FIG. 3A. In the light emitting region 21Y, on the rear surface of the light guide plate 21, a plurality of grooves 21D _Y is to form a cross-section of the saw blade shape and are arranged in succession in the Y-axis direction. The cross section of each groove 21D _Y along the Y-axis direction, the bottom angle of the Y axis negative direction is 90 ° of right isosceles triangular. Grooves 21D _Y extends in the X-axis direction, and is formed in a strip shape when viewed from the Z-axis direction. Pitch along the Y-axis direction of the groove 21D _Y is preferably 0.3mm or less than 0.005 mm. The depth of the groove 21D _Y is desirably 30% or less than 0.01% of the thickness of the light guide plate 21.

FIG. 3E shows how the light emitted from the light source 20Y travels. Light travels in the Y-axis negative direction, is incident on the inclined surface of the groove 21D _Y of the light emitting region 21Y. The inclined surface reflects a part of incident light in the positive direction of the Z-axis due to the difference in refractive index between the light guide plate 21 and air, and the reflected light is emitted toward the liquid crystal display element. The light emitted from the light source 20Y travels substantially straight in the region 21X and is not emitted in the Z-axis direction.

As shown in FIGS. 3A to 3E, a plurality of grooves 21D _X (21D _Y ) extend in the Y-axis direction (X-axis direction) and are formed in a strip shape to form a light source 20X (21Y). 20Y), the illumination light that performs planar illumination can be obtained in the light emitting region 21X (21Y) by making the light incident along the X-axis direction (Y-axis direction). The light emitted from the light source 20X (20Y) travels straight in the region 21Y (21X) without being substantially affected. For this reason, for example, by controlling the light emission of the light source 20X and the light emission of the light source 20Y independently by the control circuit, the entire surface of the light guide plate 21 (BLU entire surface) can be illuminated. It is also possible to illuminate in a part of the area. Compared with the case where the light of each of the light sources 20X and 20Y is emitted from the entire surface of the light guide plate 21, the amount of light emitted from the light sources 20X and 20Y can be reduced and low power consumption can be realized. Further, by making the light emission colors of the light source 20X and the light source 20Y different, it is possible to provide a liquid crystal display device that performs illumination with different illumination colors in the region 21X and the region 21Y and realizes various and high-quality displays.

  4A to 4C are schematic diagrams illustrating modified examples of the configuration of the light source 20.

In the example shown in FIGS. 4A and 4B (cross-sectional view of the light emitting region 21X along the line 4B-4B in FIG. 4A), the light sources 20X and 20Y include the condensing lenses 20X _b and 20Y _b in addition to the LEDs 20X _a and 20Y _a. It differs from the example shown in FIGS. Condenser lens _20X b, 20Y _b is, LED20X _a, 20Y _a is introduced into the light guide plate 21 condenses the light emitted. Since the light emitted from the light sources 20X and 20Y is more condensed and propagates through the light guide plate 21, the light utilization efficiency can be further improved and low power consumption can be realized. In addition, it is possible to suppress light leakage between the light emitting regions 21X and 21Y and perform higher quality display.

In the example shown in FIGS. 4A and 4B, each of LED20X _a, corresponding to each of LED20Y _a, individually converging lens _20X b, but placing 20Y _b, as shown in FIG. 4C, a plurality of LED20X _a one condenser lens 20X _c of the emitted light is condensed, and may be arranged one condenser lens 20Y _c for condensing light emitted in a plurality of LED20Y _a.

  5A to 5C show other examples of the configurations of the light source 20 and the light guide plate 21. FIG. 5B and 5C are cross-sectional views of the light emitting region 21X along the line 5B-5B in FIG. 5A.

In the example shown in FIG 3A~ Figure 3E, but with a LED20X _a light source 20X is arranged in the X-axis negative direction side of the light guide plate 21, as shown in FIG. 5A in this example, the light source 20X is electrically The LED 20X _a1 disposed on the X axis negative direction side of the light plate 21 and the LED 20X _a2 disposed on the X axis positive direction side are provided. Light emitted from the LED 20X _a1 travels in the light guide plate 21 in the X-axis positive direction, and light emitted from the LED 20X _a2 travels in the light guide plate 21 in the X-axis negative direction.

The present embodiment, as shown in FIG 5B, a cross section along the X-axis direction of each groove 21D _X of the light emitting region 21X is, in terms base angle are mutually equal isosceles triangle, in FIG 3A~ Figure 3E Different from the example shown. In this example, the pitch along the X-axis direction of the grooves 21D _X is preferably 0.005 mm or more and 0.3 mm or less. The depth of the groove 21D _X is desirably 30% or less than 0.01% of the thickness of the light guide plate 21.

FIG. 5C shows a traveling mode of light emitted from the LEDs 20X _a1 and 20X _a2 . The light emitted from the LEDs 20X _a1 and 20X _a2 travels in the positive X-axis direction and the negative X-axis direction, respectively, and enters the inclined surface of the groove 21D _X in the light emitting region 21X. The inclined surface reflects part of the incident light in the positive direction of the Z axis due to the difference in refractive index between the light guide plate 21 and air, so that the light emitted from the LEDs 20X _a1 and 20X _a2 is emitted toward the liquid crystal display element, respectively. To do. The light emitted from the LEDs 20X _a1 and 20X _a2 travels almost straight in the region 21Y and is not emitted in the Z-axis direction.

The light emitted from the LEDs 20X _a1 and 20X _a2 extends in the Y-axis direction and is reflected by a plurality of grooves 21D _X formed in a strip shape when viewed from the Z-axis direction. Illumination light for performing illumination can be obtained.

The light emitted from the LEDs 20X _a1 and 20X _a2 is also emitted to the back side of the light guide plate 21. For this reason, in the configuration of this example, the reflection plate or the light absorption plate 22 (see FIG. 1) is disposed close to the back surface of the light guide plate 21. By disposing the reflection plate 22, a part of the light emitted to the back surface side can be reflected and emitted from the front surface side of the light guide plate 21. When the light absorbing plate 22 is arranged, the light emitted to the back side can be absorbed.

In the configuration of this example, by turning on only one of the LEDs 20X _a1 and 20X _a2 or turning on both of them, the amount of light emitted from the light emitting region 21X can be controlled more finely. Further, by making the emission colors of the LEDs 20X _a1 and 20X _a2 different, light of a plurality of colors can be emitted from the light emitting region 21X.

Although the light source 20X is an example with a _LED20X a1, _{LED20X a2,} of LED20Y _a light source 20Y are arranged in the Y-axis positive direction side of the light guide plate 21 in addition, the LED arranged in the Y axis negative direction side It can also be set as the structure provided.

  Furthermore, the other structural example of the light-guide plate 21 is shown to FIG. 6A-FIG. 6F. Even if these configurations are used, the same effects as the example shown in FIGS. 3A to 5C can be obtained.

In the example shown in FIG. 6A, grooves 21D _X having an isosceles triangular cross section with the same base angle on the back surface of the light guide plate 21 are arranged discontinuously and at equal pitches.

In the example shown in FIG. 6B, the grooves 21D _X having a triangular cross section that is not an isosceles triangle are discontinuously arranged at an equal pitch.

In the example shown in FIG. 6C, the grooves 21D _X having a semicircular arc cross section are continuously arranged at an equal pitch.

As shown in FIG 6A~ Figure 6C, the grooves 21D _X has only to comprise a flat or curved surface non-perpendicular tilted with respect to for example the light guide plate 21 surface (exit surface). Incident from the light guide plate 21 side, light traveling in a direction substantially orthogonal to the extending direction of the groove 21D _X is reflected by the inclined surface of the groove 21D _X, it is emitted from the light guide plate 21 surface.

Incidentally groove 21D _X is other plane or curved surfaces non-perpendicular tilted with respect to the light guide plate 21 surface may include a surface parallel and plane perpendicular to the light guide plate 21 surface.

In the example shown in FIG. 6D, the grooves 21D _X having a trapezoidal cross section are discontinuously arranged at an equal pitch. Surfaces of the grooves 21D _X is a plane non-perpendicular inclined relative to the light guide plate 21 surface, and a plane parallel.

In the example shown in FIG. 6E, the grooves 21D _X having a cross-sectional shape chamfered so that the upper corner portion of the rectangle is curved are arranged discontinuously and at equal pitches. Surfaces of the grooves 21D _X is a plane parallel to the light guide plate 21 surface, vertical plane and comprised of a non-vertical inclined curved surface.

FIG. 6F shows an example in which a convex portion 21C _X protruding from the back surface of the light guide plate 21 is formed instead of the groove 21D _X. In FIG. 6F, the convex portions 21C _X having an isosceles triangular cross section are continuously arranged at an equal pitch. For example, the cross sections in which the groove shapes shown in FIGS. 3B, 5B, and 6A to 6E are turned upside down. It can be a convex part of shape.

The groove 21D _X and the convex portion 21C _X may be mixed on the back surface of the light guide plate 21.

For example, in FIGS. 6A to 6F, the groove 21D _X and the convex portion 21C _X of the light emitting region 21X have been described, but the same applies to the light emitting region 21Y.

Inside the light emitting regions 21X and 21Y, the pitches of the grooves 21D _X and 21D _Y and the convex portions 21C _X and 21C _Y can be varied.

In the example shown in FIG. 7A, in the light-emitting region 21X, groove 21D _X extending in the Y-axis direction in accordance with the distance from the light source 20X, are arranged at a short pitch along the X-axis direction. By adopting such a structure, the illumination brightness in the light emitting region 21X can be made uniform.

Although FIG. 7A shows an example in which the groove 21D _X continuously extends in the Y-axis direction, the groove 21D _X extending in the Y-axis direction may be divided as shown in FIG. 7B. For example, the dividing positions can be arranged at an equal pitch, an unequal pitch, or a mixed pitch thereof.

In the example shown in FIG. 7B, the plurality of grooves 21D _X extending in the Y axis direction are divided at the same position as the adjacent grooves 21D _X along the X axis direction, but are divided at different positions. Also good. FIG. 7C shows an example of division at a position deviated from the anti-pitch.

3A to 7C, the entire surface of the light guide plate 21 is covered with the light emitting region 21X and the light emitting region 21Y. However, the grooves 21D _X and 21D _Y and the convex portions 21C _X are formed in the surface of the light guide plate 21. , 21C _Y may not be formed.

For example, by arranging a region where the grooves 21D _X and 21D _Y and the convex portions 21C _X and 21C _Y are not formed in the boundary region between the light emitting region 21X and the light emitting region 21Y, the illumination light of the light emitting region 21X and the illumination light of the light emitting region 21Y are arranged. However, an effect of making it difficult to mix in the vicinity of the boundary region is obtained. Even when illumination light is emitted from only one of the light emitting region 21X and the light emitting region 21Y, light leakage to the other region is suppressed. Similarly, light leakage can be suppressed by forming a light leakage suppression structure by forming a groove having a well-shaped cross section in the boundary region or by disposing black resin.

  FIG. 8 is a schematic plan view showing the effective display unit 50 of the liquid crystal display device according to the embodiment. Within the rectangular effective display section 50, a clock / air conditioner operation display area 51, a left temperature display area 52, a right temperature display area 53, and a defroster display area 54 are defined, and each of the areas 51 to 53 includes a plurality of areas. One segment display section is arranged in the segment display section, area 54.

  In the clock / air-conditioner operation display area 51, for example, a current time display or a display related to the air-conditioner operation is performed. In the left and right temperature display areas 52 and 53, the left and right indoor temperatures are displayed, respectively, and in the defroster display area 54, the operating state of the defroster is displayed.

  The area 51 is displayed in white. In the areas 52 and 53, display is performed in a plurality of colors such as red display when the room temperature is high, blue display when the room temperature is low, and green display when the temperature is comfortable. In the area 54, orange display is performed when the defroster is operated. Such an information display device is disposed, for example, in a console (HVAC display section) between a driver seat and a passenger seat in an automobile.

  Although the liquid crystal display device according to the embodiment is a segment display device that displays only characters, numbers, symbols, etc., for example, a display device that includes a dot matrix display part and performs a display in which segment display and dot display are mixed. It can be.

  9A to 9C are schematic views showing the light guide plate 21 of the liquid crystal display device according to the first embodiment.

Refer to FIG. 9A. Light emitting areas 21X ₁ , 21X ₂ , 21X ₃ , 21Y are defined in the in-plane direction of the light guide plate 21. The light guide plate 21 has an effective display section 50 so that illumination light emitted from the light emitting areas 21X ₁ , 21X ₂ , 21X ₃ , 21Y is incident on the areas 52, 53, 54, 51 (segment display section), respectively. Are arranged on the negative side of the Z-axis. In the drawing, the display units included in the areas 51 to 54 of the effective display unit 50 are also shown.

The light sources 20X ₁ , 20X ₂ , and 20X ₃ are arranged on the X axis negative direction side of the light guide plate 21, and the light source 20Y is arranged on the Y axis positive direction side, and include, for example, LEDs and a condenser lens. The LEDs of the light sources 20X ₁ and 20X ₂ emit red (R), green (G), and blue (B) light. LED light source 20X ₃ is to emit orange light, LED light source 20Y emits white light. The control circuit of the circuit board 32 (see FIG. 1) controls the light emission of each light source 20X ₁ , 20X ₂ , 20X ₃ , 20Y. The control circuit controls the color of light emitted from the LEDs of the light sources 20X ₁ and 20X ₂ according to, for example, the room temperature. Light emitted from the light sources 20X ₁ , 20X ₂ , and 20X ₃ travels in the light guide plate 21 in the X-axis positive direction, and light emitted from the light source 20Y travels in the Y-axis negative direction.

_On the X axis positive direction side of the light emitting region 21X1, a light leakage suppression structure 35a such as a groove having a well-shaped cross section or a black resin is disposed along the Y axis direction. Further, in the X-axis positive direction and the Y-axis positive direction side of the light emitting region 21X _2, light leakage suppressing structure 35b is arranged along the Y-axis direction and the X-axis direction, X-axis positive direction side of the light emitting region 21X ₃ The light leakage suppression structure 35c is arranged along the Y-axis direction. The arrangement region of the light leakage suppression structures 35a, 35b, and 35c is a boundary region between the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ and the light emitting region 21Y.

FIG. 9B shows cross sections in the light emitting regions 21X ₁ , 21X ₂ , and 21X ₃ of the light guide plate 21. In the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , a plurality of grooves 21D _X1 , 21D _X2 , 21D _X3 are continuous in the X-axis direction so that a plurality of grooves 21D _X1 , 21D _X2 , 21D _X3 form a saw-tooth shaped cross section on the back surface of the light guide plate 21 Are arranged. The cross sections of the grooves 21D _X1 , 21D _X2 and 21D _X3 along the X-axis direction have a right isosceles triangular shape with a base angle of 90 ° on the X-axis positive direction side. The grooves 21D _X1 , 21D _X2 and 21D _X3 extend in the Y-axis direction and are formed in a strip shape when viewed from the Z-axis direction.

Light emitted from the light sources 20X ₁ , 20X ₂ , and 20X ₃ is reflected in the Z axis positive direction by the inclined surfaces of the grooves 21D _X1 , 21D _X2 , and 21D _X3 of the light emitting regions 21X ₁ , 21X ₂ , and 21X ₃ , respectively. 21 exits to the areas 52, 53, and 54 from the exit surface. The color of the light emitted from the light emitting regions 21X ₁ and 21X ₂ is red, green, or blue, and the color of the light emitted from the light emitting region 21X ₃ is orange. Light emitted from the light source 20X _3, in the region 21Y, straight without being substantially deflected. In addition, the light incident on the light leakage suppression structures 35a, 35b, and 35c is reflected or absorbed, for example, and the progress is blocked.

FIG. 9C shows a cross section of the light guide plate 21 in the light emitting region 21Y. On the rear surface of the light guide plate 21, a plurality of grooves 21D _Y is to form a cross-section of the saw blade shape and are arranged in succession in the Y-axis direction. The cross section of each groove 21D _Y along the Y-axis direction, the bottom angle of the Y axis negative direction is 90 ° of right isosceles triangular. Grooves 21D _Y extends in the X-axis direction, a strip-shaped when viewed from the Z-axis direction.

Light emitted from the light source 20Y is reflected in the Z-axis positive direction at the inclined surface of the groove 21D _Y of the light emitting region 21Y, emitted from the emitting surface of the light guide plate 21 in the region 51. The light emitted from the light emitting region 21Y is white. The light emitted from the light source 20Y travels straight in the regions 21X ₁ and 21X ₃ without being substantially deflected. In addition, the light incident on the light leakage suppression structure 35b is reflected or absorbed, for example, and is blocked from traveling.

In the embodiment of the present application, the light leakage suppression structures 35a, 35b, and 35c are arranged, but the grooves 21D are replaced with the light leakage suppression structures 35a, 35b, and 35c or together with the light leakage suppression structures 35a, 35b, and 35c. _A region where _X1 , 21D _X2 , 21D _X3 , 21D _{Y and the} like are not formed may be arranged. For example, light leakage to the adjacent region is suppressed, and mixing of light emitted from each of the light sources 20X ₁ , 20X ₂ , 20X ₃ , 20Y and the like is suppressed. Illumination light of the intended color including the boundary region can be emitted from the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , 21Y. By switching the display portion of the liquid crystal display element (regions 52, 53, 54, 51) to which the illumination light emitted from each of the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , 21Y is incident, a desired display color can be obtained. A display pattern can be obtained.

  Note that the BLU illumination lighting state of the plurality of segment display units arranged in the areas 51 to 54 shown in FIG. 8 is controlled independently, for example, in a sidelight type BLU using a divided light guide plate, the defroster display area 54 Because it becomes a floating island, it is impossible. In addition, if the corresponding light emitting area for illuminating each of the areas 51 to 54 has a bathtub structure in which a partition wall is provided at the boundary portion of each light emitting area, and a direct type configuration in which a light source is disposed on the bottom surface thereof is possible. However, when the display pattern is small or the interval between adjacent display units is small, it is considered that the intended display state may not be realized.

  In the liquid crystal display device according to the first embodiment, a single light guide plate 21 is used, and the BLU illumination lighting states of the plurality of segment display units arranged in the areas 51 to 54 are reduced with a small number of parts. It can be controlled for each. Since illumination light can be emitted from a partial region of the light guide plate 21, power consumption by the BLU is reduced. In addition, the liquid crystal display device according to the first embodiment can realize various and high-quality displays by using illumination lights of a plurality of colors.

  In the first embodiment, the effective display unit 50 is divided into a plurality of areas 51 to 54, and the entire surface of each area 51 to 54 is illuminated. However, in the segment display device, since the area occupied by the background portion is large, the light utilization efficiency of the BLU is low, and the luminance of the background portion tends to be higher than that of the self-luminous display device due to light leakage of the polarizing plate.

  In that regard, for example, by providing the groove with a saw-tooth shaped cross section only on the back surface of the light guide plate 21 directly under the segment display portion (Z-axis negative direction), the light utilization efficiency of the BLU is improved. It is expected that the background portion of the effective display unit 50 is not illuminated by BLU, and the luminance at the time of front observation can be made substantially zero, that is, a high contrast display equivalent to that of a self-luminous display device can be realized. However, in the structure in which only the display unit is illuminated with the BLU, it is necessary to make the alignment accuracy of the liquid crystal display element and the BLU extremely high. Further, when the display surface is observed from a deep angle with respect to the normal direction, due to parallax, Thus, a display state is obtained in which the outline of the display unit is missing.

  FIG. 10 is a schematic view showing the light guide plate 21 of the liquid crystal display device according to the second embodiment.

Light emitting areas 21X ₁ , 21X ₂ , 21X ₃ , 21Y are defined in the in-plane direction of the light guide plate 21. In the second embodiment, the light emitting region 21X _1, offset from the contour of the segment display portion on the outside included in the left side temperature display area 52, for example, the display unit of the constant from the periphery length, and 5mm offset as an example to give The shape is the same as the area to be formed. Further, areas obtained by offsetting the light emitting areas 21X ₂ , 21X ₃ , and 21Y by 5 mm outward from the outlines of the segment display portions included in the right temperature display area 53, the defroster display area 54, and the clock / air conditioner operation display area 51, respectively. And the same shape. The light guide plate 21 is arranged on the Z axis negative direction side of the effective display unit 50 so that the illumination light emitted from the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , 21Y enters the corresponding segment display unit. .

The light sources 20X ₁ , 20X ₂ , 20X ₃ , 20Y and the light leakage suppression structures 35a, 35b, 35c are the same as those in the first embodiment. The cross sections (see FIGS. 9B and 9C) of the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ and 20Y of the light guide plate 21 are also the same as in the first embodiment.

The light emitted from the light sources 20X ₁ , 20X ₂ , 20X ₃ , and 20Y is Z-axis positive on the inclined surfaces of the grooves 21D _X1 , 21D _X2 , 21D _X3 , and 21D _Y of the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , and 21Y, respectively. The light is reflected in the direction and exits from the exit surface of the light guide plate 21 to the corresponding segment display unit. The color of the light emitted from the light emitting regions 21X ₁ and 21X ₂ is red, green, or blue, and the color of the light emitted from the light emitting region 21X ₃ is orange. Further, the light emitted from the light emitting region 21Y is white. Light emitted from the light source 20X _3, in the region 21Y, straight without being substantially deflected. The light emitted from the light source 20Y travels straight in the regions 21X ₁ and 21X ₃ without being substantially deflected. The light incident on the light leakage suppression structures 35a, 35b, and 35c is reflected or absorbed, for example, and is blocked from traveling.

In the second embodiment, the light emitting areas 21X ₁ , 21X ₂ , 21X ₃ , 21Y have a shape obtained by offsetting 5 mm outward from the outline of the corresponding display part, and do not illuminate most of the background part. Thus, the light utilization efficiency of the BLU is improved (power consumption is reduced) and the luminance of the background portion is remarkably low, so that high contrast and high quality display equivalent to that of the self-luminous display device can be realized. The alignment accuracy between the liquid crystal display element and the BLU is relaxed by the offset amount. Further, even when observing from a deep polar angle, the outline of the display portion is prevented from being chipped. Furthermore, various displays can be realized by illumination light of a plurality of colors.

  The inventors of the present application observed the appearance of the display surface of the liquid crystal display device according to the second embodiment, and as a result, it was confirmed that there was no outline at an angle within 45 ° with respect to the normal direction.

Furthermore, in the second embodiment, the grooves 21D _X1 , 21D _X2 , 21D _X3 , and 21D _Y are not arranged between the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , and 20Y than the first embodiment. Since the portion is wide, light leakage and color mixing between the adjacent light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , and 20Y are further suppressed.

  In the second embodiment, the offset amount is set to 5 mm. However, by increasing the offset amount, it is possible to prevent the outline from being lost even when observing from a deeper polar angle.

  Further, when the interval between adjacent segment display portions is small, a plurality of segment display portions may be set as one unit and offset outward from the outer shape of the region.

11A and 11B are schematic views showing the light guide plate 21 of the liquid crystal display device according to the third embodiment. The third embodiment, a region for emitting illumination light to the display unit for performing time display, that form a light emitting region 21X _4, and, second in including a light source 20X ₄ in X-axis positive direction side of the light guide plate 21 This is different from the second embodiment.

Source 20X ₄ includes, for example, a LED and a condenser lens, and emits white light. Light emission of the light source 20X ₄ is controlled by the control circuit of the circuit board 32 (see FIG. 1). Light emitted from the light source 20X ₄ travels within the light guide plate 21 in the X axis negative direction, is incident on the light-emitting region 21X _4. Emission region 21X ₄ is the same shape and area obtained from the contour of the segment display unit for performing time display and 5mm offset outwardly. Light emitted from the light source 20X _4, in the region 21Y, straight without being substantially deflected.

FIG. 11B shows a cross section in the light emitting region 21 </ b> X ₄ of the light guide plate 21. On the back surface of the light guide plate 21, a plurality of grooves 21 _</ b> D _X <b> ₄ are continuously arranged in the X-axis direction so as to form a saw-tooth shaped cross section. The cross section of each groove 21D _X4 along the X-axis direction is a right-angled isosceles triangle having a base angle of 90 ° on the X-axis negative direction side. The groove 21D _X4 extends in the Y-axis direction and has a strip shape when viewed from the Z-axis direction.

Light emitted from the light source 20X ₄ is reflected in the Z-axis positive direction at the inclined surface of the groove 21D _X4 emission region 21X _4, from the exit surface of the light guide plate 21, is emitted to the segment display unit for performing time display.

In the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ and the light emitting region 21X ₄ , the non-perpendicular inclined surfaces of the grooves 21D _X1 , 21D _X2 , 21D _X3 , 21D _X4 face in opposite directions (see FIG. 9B). In the third embodiment, the non-vertical inclined surfaces of the grooves 21D _X1 , 21D _X2 and 21D _X3 are arranged so as to face the light sources 20X ₁ , 20X ₂ and 20X ₃ (X-axis negative direction), and the grooves 21D _X4 non-vertical inclined plane, but are arranged so as to face the light source 20X ₄ side (X-axis positive direction), non-vertical inclined surface of the groove _{21D X1, 21D X2, 21D X3} is, the light source _{20X 1,} 20X 2, 20X of ₃ may be disposed so as to face the opposite side (X-axis positive direction) _3, and the non-vertical inclined surface of the groove 21 _</ b _> D _X <b> ₄ may be disposed to face the opposite side (X-axis negative direction) from the light source 20 </ b> X ₄ . By arranging the grooves 21D _X1 , 21D _X2 , 21D _X3 , and 21D _X4 in this way, mixing of light traveling in the X-axis positive direction and light traveling in the X-axis negative direction is suppressed. In the third embodiment, light leakage suppressing structure 35c is formed in the emitting region 21X ₃ boundary region of the light emitting region 21X _4, the light emitted from the light source 20X _3, the light emitted from the light source 20X ₄ Suppresses mixing.

The liquid crystal display device according to the third embodiment, for example, when air conditioning operation is off, the light source 20X ₄ to emit light, the light source _{20X 1,} without emission from 20X 2, 20Y, so as to emit light source 20X ₃ at defroster operation Control is performed, and the power consumption by the BLU can be reduced as compared with the second embodiment.

  As mentioned above, although this invention was demonstrated along the Example etc., this invention is not restrict | limited to these.

For example, in the embodiment, the light sources 20X ₁ and 20X ₂ emit a plurality of lights, but other light sources may emit a plurality of lights.

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.

  For example, it can be used for an on-vehicle information display device such as a speedometer or a display for displaying an air conditioner operation. In addition, it can be used for display in indoor facilities including home appliances such as an air conditioner, a water heater, a gas stove, and a microwave oven, and further for display in an audio device or the like.

10a Front side board (common board)
10b Back side substrate (segment substrate)
11a Front side transparent substrate 11b Back side transparent substrate 12a Front side transparent electrode (common electrode)
12b Back side transparent electrode (segment electrode)
13a front orientation film 13b backside alignment layer 14a front viewing angle compensation plate 14b backside viewing angle compensation plate 15a front polarizer 15b rear polarizer 16 liquid crystal layer 17 external extraction electrode terminals _{20,20X, 20X 1, 20X 2,} 20X 3, 20X 4 20Y light source 20X _a , 20X _a1 , 20X _a2 , 20Y _a LED
_{20X b, 20Y b, 20X c} , 20Y c condenser lens 21 light guide plate _{21X, 21X 1, 21X 2,} 21X 3, 21X 4, 21Y emitting region _21C x, 21C _Y protrusion _{21D X, 21D X1, 21D X2} , 21D _X3 , 21D _X4 , 21D _Y groove 22 Reflector or light absorbing plate 23 Diffusion plate 31 Lead frame 32 Circuit boards 35a, 35b, 35c Light leakage suppression structure 40 Housing (housing)
50 Effective display section 51 Clock / air conditioner operation display area 52 Left temperature display area 53 Right temperature display area 54 Defroster display area

Light emitting areas 21X ₁ , 21X ₂ , 21X ₃ , 21Y are defined in the in-plane direction of the light guide plate 21. In the second embodiment, a light emitting region 21X _1, offset from the contour of the segment display portion on the outside included in the left side temperature display area 52, for example, the display unit of the constant from the contour length, 0.5 mm offset as an example The shape was the same as that obtained in the above. The light emitting areas 21X ₂ , 21X ₃ , and 21Y are obtained by offsetting 0.5 mm outward from the outlines of the segment display portions included in the right temperature display area 53, the defroster display area 54, and the clock / air conditioner operation display area 51, respectively. The shape is the same as the area to be formed. The light guide plate 21 is arranged on the Z axis negative direction side of the effective display unit 50 so that the illumination light emitted from the light emitting regions 21X ₁ , 21X ₂ , 21X ₃ , 21Y enters the corresponding segment display unit. .

In the second embodiment, the light emitting areas 21X ₁ , 21X ₂ , 21X ₃ , 21Y have a shape obtained by offsetting 0.5 mm outward from the outline of the corresponding display part, and illuminate most of the background part. Therefore, the light utilization efficiency of the BLU is improved (power consumption is reduced), the luminance of the background portion is remarkably low, and high-contrast and high-quality display equivalent to that of the self-luminous display device can be realized. The alignment accuracy between the liquid crystal display element and the BLU is relaxed by the offset amount. Further, even when observing from a deep polar angle , the lack of the outline of the display unit is suppressed. Furthermore, various displays can be realized by illumination light of a plurality of colors.

In the second embodiment, the offset amount is 0.5 mm . However, by increasing the offset amount, it is possible to prevent the outline from being lost even when observing from a deeper polar angle.

Source 20X ₄ includes, for example, a LED and a condenser lens, and emits white light. Light emission of the light source 20X ₄ is controlled by the control circuit of the circuit board 32 (see FIG. 1). Light emitted from the light source 20X ₄ travels within the light guide plate 21 in the X axis negative direction, is incident on the light-emitting region 21X _4. Emission region 21X ₄ is the same shape and area obtained from the contour of the segment display unit for performing time display with 0.5mm offset outwardly. Light emitted from the light source 20X _4, in the region 21Y, straight without being substantially deflected.

Claims (12)

A normally black liquid crystal display element comprising a plurality of segment display units including a first segment display unit and a second segment display unit, wherein at least one segment display unit is displayed in a color different from other segment display units When,
An illumination device that includes a first light source, a second light source, and a light guide plate into which light emitted from the first and second light sources is introduced, and that emits illumination light to the liquid crystal display element;
A circuit for driving the liquid crystal display element and emitting the first and second light sources;
The first light source emits first light traveling in the light guide plate with the direction parallel to the first direction as an optical axis direction,
The second light source emits second light traveling in the light guide plate with the direction parallel to the second direction orthogonal to the first direction as an optical axis direction,
The light guide plate is a first light emission region and a second light emission region, reflects the first light with a higher reflectance than the second light emission region, and emits the light from an emission surface to the first segment display unit. A first light-emitting region, and a second light-emitting region that reflects the second light with a higher reflectance than the first light-emitting region and emits the light from the emission surface to the second segment display unit,
The first light emitting region includes a concave portion or / and a convex portion that extends in a direction parallel to the second direction and reflects the first light,
The liquid crystal display device, wherein the second light emitting region includes a concave portion and / or a convex portion that extends in a direction parallel to the first direction and reflects the second light.   2. The liquid crystal display device according to claim 1, wherein the concave portions and / or convex portions of the first and second light emitting regions have a surface that is inclined non-perpendicularly with respect to an emission surface of the light guide plate.   The first light source and the second light source emit light of different colors, and a light leakage suppression structure is formed in a boundary region between the first light emitting region and the second light emitting region. 3. The liquid crystal display device according to 1 or 2.   4. The liquid crystal display device according to claim 1, wherein a region where no concave portion and / or convex portion is formed is disposed in a boundary region between the first light emitting region and the second light emitting region.   5. The liquid crystal display device according to claim 1, wherein at least one of the first light source and the second light source emits light of a plurality of colors.   The said 1st, 2nd light emission area | region is the same shape as the area | region obtained by offsetting outward from the outline of the said 1st, 2nd segment display part, respectively. Liquid crystal display device. Furthermore,
The liquid crystal display element includes a third segment display unit,
The illumination device includes a third light source in which emitted light is introduced into the light guide plate,
The circuit causes the third light source to emit light;
The third light source emits third light that travels in the direction opposite to the first light in the light guide plate, with the direction parallel to the first direction as the optical axis direction,
The light guide plate includes a third light emitting region that reflects the third light with a higher reflectance than the second light emitting region and emits the third light from an emission surface to the third segment display unit,
The third light emitting region includes a concave portion or / and a convex portion that extends in a direction parallel to the second direction and reflects the third light,
The concave portion or / and the convex portion of the third light emitting region have a surface that is inclined non-perpendicular to the exit surface of the light guide plate,
The non-vertical inclined surface of the concave portion or / and convex portion of the first light emitting region and the non-vertical inclined surface of the concave portion or / and convex portion of the third light emitting region are parallel to the first direction, And facing opposite directions,
The liquid crystal display device according to claim 2, wherein a light leakage suppression structure is formed in a boundary region between the first light emitting region and the third light emitting region.   The liquid crystal display device according to claim 1, wherein the liquid crystal display element is a monodomain vertical alignment type liquid crystal display element or a multidomain vertical alignment type liquid crystal display element.   The liquid crystal display device according to claim 1, wherein the first light source includes a light emitting source and a condenser lens that condenses light emitted from the light emitting source.   The concave portions or / and convex portions of the first light emitting region are arranged at a short pitch along the first direction as the distance from the first light source increases, and / or the second light emission. 10. The liquid crystal display according to claim 1, wherein the concave portions or / and the convex portions of the region are arranged at a short pitch along the second direction as the distance from the second light source increases. apparatus.   The liquid crystal display device according to any one of claims 1 to 10, wherein a concave portion or / and a convex portion of the first or / and second light emitting region are divided. In the first light emitting region, the concave portion or / and the convex portion are divided at a position different from the concave portion or / and the convex portion adjacent to each other along the first direction, or / and the second light emission. The liquid crystal display device according to claim 11, wherein in the region, the concave portion or / and the convex portion are divided at a position different from the concave portion or / and the convex portion adjacent to each other along the second direction.