JP2009164026A - Lighting unit, liquid crystal device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting unit provided with a light source arrangement region formed by arranging a plurality of light sources, in which there is provided a lighting structure capable of improving uniformity of lighting luminance over an entire lighting range of the lighting unit, and suppressing a production cost and power consumption. <P>SOLUTION: The lighting unit 110 includes a light source arrangement region A where a plurality of light sources 112 are planarly arranged on a substrate 111 and a light diffusion plate 116 arranged at a front side of the light source arrangement region A. Therein, each of the light sources 112 has a light emitting distribution having a center in a direction of a normal line of an arrangement plane, and a reflecting slope 115a is provided which encloses the light source arrangement region A on the substrate 111, and which inclines outside from the normal line direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an illumination unit, a liquid crystal device, and an electronic apparatus, and more particularly to a configuration of an illumination unit including a plurality of arranged light sources and a light diffusion plate arranged on the front side thereof.

  In general, an illuminating unit called a backlight is disposed behind a transmissive (including transflective, including the following) liquid crystal panel, and the illuminating unit illuminates the liquid crystal panel from behind to drive the liquid crystal panel. A desired display corresponding to the state is formed. As this type of lighting unit, for example, a light source such as an LED (light emitting diode) or a cold cathode tube at the end of a light guide plate as a component constituting a small display body such as one mounted on a mobile phone. The so-called side light type (edge light type) illumination is formed by arranging a light source and gradually emitting light from the light exit surface while propagating the light incident from the end surface of the light guide plate. The unit is known.

  However, if the display area is relatively large, such as an in-vehicle monitor or a liquid crystal television, the amount of light necessary for the illumination unit increases, and the above structure cannot be used. In addition, when using a technology that increases the range of gradation or chromaticity of the display image by changing the in-plane distribution or hue distribution of the illumination luminance according to the display image, the light source is arranged within the plane of the light source. However, the above-mentioned sidelight type lighting unit, which cannot change the brightness and hue, cannot be used. For this reason, a so-called direct type illumination unit in which a light diffusing plate is arranged on the front side of the light source is becoming mainstream. In recent years, LEDs have been increasingly adopted as the direct light source due to the improvement of the luminous efficiency and luminance of the LEDs, and the light emitting units can be arranged by arranging the LEDs vertically and horizontally on a plurality of planes. You can see what constitutes it.

  However, when a plurality of LEDs are arranged in a plane as described above and a light diffusing plate is arranged on the front side to form an illumination unit, the most uniform uniformity of in-plane luminance as a planar light source is most important. As a priority issue, there is a serious problem that the outer peripheral portion, particularly the corner portion, becomes darker than the central portion of the LED array region.

Therefore, conventionally, a method has been proposed in which the arrangement interval of a plurality of LEDs mounted on a substrate is made smaller in the outer peripheral portion (four corner portions) than the central portion of the arrangement region, thereby eliminating dark portions at the four corners and increasing the uniformity of in-plane luminance. (For example, refer to Patent Document 1 below).
JP 2006-120644 A

  By the way, in the conventional lighting unit, the uniformity of the in-plane luminance of the lighting unit is improved by increasing the LED array density at the outer peripheral part of the light source array region rather than the center part. There is a problem that it is necessary to increase the number of LEDs arranged as compared with the conventional case, and the manufacturing cost and power consumption increase.

  Therefore, the present invention solves the above-mentioned problems, and the problem is that in an illumination unit having a light source array region in which a plurality of light sources are arrayed, the illumination brightness is uniform over the entire illumination range of the illumination unit. It is to realize an illumination structure capable of improving the performance and suppressing the manufacturing cost and power consumption.

  In view of such circumstances, the illumination unit of the present invention includes a light source array region in which a plurality of light sources are arranged in a plane on a substrate, and a light diffusion plate disposed on the front side of the light source array region. An illumination unit, wherein the light source has a light radiation distribution centered on a normal direction of an array plane, surrounds the light source array region on the substrate, and has an inclined reflective surface inclined outward from the normal direction. It is characterized by having.

  In general, when a plurality of light sources are evenly distributed, the brightness at the center of the light source array area increases and the brightness at the outer periphery of the light source array area decreases. In particular, the corners of the light source array area (the light source array area is rectangular). When configured in a shape, the luminance at the four corners is significantly reduced. However, according to the present invention, by providing an inclined reflection surface inclined outward from the normal direction, a high emission angle (optical axis) directed toward the periphery of the light source array region among light emitted obliquely from a plurality of light sources. (Or an angle with respect to the normal direction) Since the light is reflected by the inclined reflecting surface and has a low emission angle and is directed obliquely forward, the light source array area in the distribution of light incident on the light diffusion plate, particularly in the corners A reduction in luminance can be suppressed, and it becomes easy to make the in-plane luminance distribution of the illumination unit uniform as a whole.

  In one aspect of the present invention, the light intensity distribution that directly enters the light diffusing plate without passing through the inclined reflecting surface is configured to be higher at the outer peripheral portion than at the central portion of the light source array region. According to this, the light intensity distribution of the light source array region is configured to be higher at the outer periphery than the central portion, so that the light that goes to the periphery of the light source array region reaches the inclined reflecting surface directly, particularly at a high emission angle. Since the amount of light to be generated can be increased, the effect of improving the in-plane uniformity of luminance by the inclined reflecting surface can be enhanced, and the height of the inclined reflecting surface required to obtain the desired in-plane uniformity is reduced. Therefore, the apparatus can be thinned.

  As a specific configuration of the above aspect, for example, the light intensity distribution is set by increasing the light emission luminance of the light source arranged at the outer peripheral portion than the light emission luminance of the light source arranged at the central portion of the light source arrangement region. You may get. In some cases, the light intensity distribution is obtained by reducing the arrangement density of the light sources in the light source arrangement region at the center and increasing the density at the outer periphery.

  In another aspect of the invention, the inclined reflecting surface is provided on an inclined inner surface of an integral frame member surrounding the light source array region. According to this, it becomes easy to assemble by using an integral frame member, and the positional accuracy of the inclined reflecting surface can be increased. In this case, for example, a reflective layer may be formed on the inclined inner surface of the frame member to form an inclined reflective surface, or the frame member itself may be made of a light reflective material and the inclined The inner surface can be used as an inclined reflecting surface as it is.

  Next, a liquid crystal device according to the present invention includes a light source array region in which a plurality of light sources are arrayed on a substrate, a light diffusion plate disposed on the front side of the light source array region, and a front surface of the light diffusion plate. A transmissive liquid crystal panel disposed on a side of the light source, wherein the light source has a light radiation distribution centered on a normal direction of an array plane, and surrounds the light source array region on the substrate. And an inclined reflecting surface inclined outward from the normal direction.

  In one aspect of the present invention, the light intensity distribution that directly enters the light diffusing plate without passing through the inclined reflecting surface is configured to be higher in the outer peripheral portion than in the central portion of the light source array region.

  In another aspect of the present invention, a planar range of the driving area of the liquid crystal panel is limited to be within the light source arrangement area. According to this, since the reflected light from the inclined reflection surface formed around the light source array region can be used effectively, it becomes easy to ensure the uniformity of the luminance in the planar range. However, even if the plane range of the drive region is limited within the formation position of the inclined reflection surface, or only limited to the inner side of the formation position, the effect of uniformizing the luminance by the reflected light of the inclined reflection surface can be obtained. It is possible to get.

  Next, an electronic apparatus according to the present invention includes the liquid crystal device according to any one of the above, and a control driving unit that controls and drives the liquid crystal device. As such an electronic device, an electronic device including a display unit such as a monitor device, a television receiver, or a navigation device is preferable in that display quality can be improved by improving the uniformity of luminance of illumination light.

[First Embodiment]
Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic longitudinal sectional view of a liquid crystal device 100 according to an embodiment of the present invention, and FIG. 2 is a plan view of a light emitting unit of an illumination unit 110 incorporated in the liquid crystal device 100 according to the first embodiment.

  The liquid crystal device 100 according to the present embodiment includes an illumination unit 110 that constitutes a planar light source, and a liquid crystal panel 120 in which a liquid crystal 124 is sealed between a pair of panel substrates 121 and 122 made of a transparent material such as glass or plastic. Are provided.

  The illumination unit 110 includes a substrate 111 made of a printed circuit board (PCB), a flexible printed circuit board (FPC), and the like, and a light source made up of a plurality of LEDs mounted on the substrate 111 (essentially a point light source in the illustrated example). And a frame 114 that surrounds a virtual plane region (hereinafter simply referred to as “light source array region A”) on the substrate 111 on which a plurality of light sources 112 are arranged. Part. A light diffusion plate 116 is disposed on the front side of the light emitting unit. A predetermined interval is secured between the light source 112 and the light diffusing plate 116 in order to ensure the uniformity of luminance. The predetermined interval depends on the size of the light source 112 (usually having a square planar shape with one side of 1-5 mm) and the light diffusion characteristics of the light diffusion plate 116, but is usually about 5-10 mm. .

  In the present specification, the light source array region A is a range in which a peripheral portion having a width half the average light source array interval is added to the outer peripheral side of the light source arranged on the outermost periphery.

  The light sources 112 are arranged vertically and horizontally (that is, planarly) on the substrate 111. In the illustrated example, the plurality of light sources 112 are arranged in a matrix (that is, in the vertical direction and the horizontal direction) at regular intervals (that is, periodically in both the vertical direction and the horizontal direction) as shown in FIG. Have. The surface of the substrate 111 other than the light source 112 is covered with a white or metallic reflective layer 113. In addition, instead of providing the reflective layer 113 separately as in the illustrated example, the substrate 111 itself may be made of a reflective material such as white polyethylene or an aluminum plate.

  A frame body 114 having a rectangular shape in plan view is disposed around the substrate 111. The frame body 114 is provided with an inclined inner surface inclined obliquely inward, and a reflective layer 115 is formed on the inclined inner surface, and the reflection The surface of the layer 115 constitutes the inclined reflecting surface 115a. However, the frame body 114 may be made of a reflective material such as white polyethylene or an aluminum plate, and the inclined inner surface itself may constitute an inclined reflecting surface.

  The inclined reflecting surface 115a is limited to the illustrated example as long as it is inclined outward from the normal direction of the arrangement plane (virtual plane on which the light sources are arranged), that is, inclined to the light source arrangement area A side. The inclination angle θ is not particularly limited as long as it is greater than 0 degrees and less than 90 degrees, but is preferably within a range of 25 to 85 degrees in order to improve luminance uniformity described below, and particularly 30. It is desirable to be within the range of -75 degrees. However, the range or optimum value of these inclination angles is the radiation distribution of light with a high emission angle from the light source array area A, the distance between the outer edge of the light source array area A and the inclined reflecting surface 115a, and the drive area B (illumination range). Varies depending on the size of the room. Specifically, when the output angle distribution of the light incident on the inclined reflecting surface 115a is biased to a higher angle as a whole, when the range of the drive region B is wide, a relatively low range, for example, 25-50 degrees. In the case where the emission angle distribution is biased to a lower angle as a whole, when the range of the drive region B is narrow, it is preferable that the range is relatively high, for example, 50 to 85 degrees.

  In the illustrated example, since the frame body 114 is advantageous in ensuring ease of assembly and mounting accuracy, the frame body 114 is composed of a rectangular frame-shaped integral frame member. In addition, the planar shape is not limited to the rectangular frame shape, and any shape that surrounds the light source array region A (a planarly closed shape) may be used.

  Further, in the illustrated example, the frame body 114 is arranged so as to be fitted to the outer peripheral edge of the substrate 111. For example, when the substrate 111 has an outer peripheral portion extending outside the light source array region A, the light source array As long as it is an aspect surrounding the region A, it may be disposed on the front side of the outer peripheral portion. Furthermore, the substrate 111 and the frame body 114 may be integrally formed.

  The light diffusing plate 116 is for improving the uniformity of the illumination light irradiated from the light emitting unit, and may be any one as long as it has a predetermined haze (HAZE; haze value). The haze range is in the range of 30-90%, and particularly preferably in the range of 60-80%. As the light diffusion plate 116, for example, a synthetic resin sheet such as one obtained by dispersing fine translucent particles having different refractive indexes in a transparent substrate can be used. Moreover, what formed the fine unevenness | corrugation (rough surface) in at least any one surface of the front and back of a transparent base material may be used.

  On the further front side of the light diffusing plate 116, light collecting plates 117 and 118 made of a prism sheet or the like are arranged. These are a kind of optical sheet together with the light diffusion plate 116. The condensing plates 117 and 118 condense the direction of the light emitted from the light diffusing plate 116 toward the optical axis (vertical axis in the illustrated example) of the liquid crystal panel 120, and the light that contributes to the display of the illumination light. Increase the rate. In the example shown in the figure, the pair of light collectors 117 and 118 are arranged in such a manner that the postures of the prisms are orthogonal to each other, so that the luminance of the illumination light emitted from the light emitting unit is increased as a whole. In addition, the light collecting plate is not limited to the illustrated example, and may be one or three or more, or may be configured such that the light collecting plate itself is not provided.

  On the other hand, the liquid crystal panel 120 has a cell structure in which the panel substrates 121 and 122 are bonded together with a sealing material 123 and the liquid crystal 124 is sealed between the substrates, and an electric field application (not shown) is applied on the inner surfaces of the panel substrates 121 and 122. The structure (electrode, switching element, etc.) is provided so that the alignment state of the liquid crystal can be changed for each of a plurality of pixels. Polarizing plates 125 and 126 are disposed (attached) on the outer surfaces of the panel substrates 121 and 122.

  In the present embodiment, as shown in FIG. 2, a plurality of light sources 112 are evenly distributed along the arrangement plane in the light source arrangement area A. Further, the light source 112 has a light emission distribution centered on the normal direction of the arrangement plane. In this case, when all the light sources 112 have substantially the same light radiance, if the inclined reflection surface 115a does not exist, the luminance of the central portion Ac of the light source array region A is high and the luminance of the outer peripheral portion Ao. Becomes lower. In particular, the brightness of the corner Ax often decreases further than other portions.

  However, in the present embodiment, the inclined reflection surface 115a surrounding the light source array region A is provided, so that light with a high emission angle that travels from the light source array region A toward the light diffusion plate 116 without being directed to the light is reflected. Therefore, the luminance of the outer peripheral portion Ao can be increased. In particular, in the corner portion Ax, the inclined reflection surfaces 115a on the sides adjacent to each other around the rectangular light source array region A are close to each other, so that the luminance improvement effect is higher than that of the other outer peripheral portion Ao. Therefore, the in-plane uniformity of the luminance within at least the light source array region A can be improved as compared with the case where the inclined reflecting surface 115a is not provided.

  In the above embodiment, the planar range of the drive region (region in which controllable pixels are arranged) B of the liquid crystal panel 120 is limited to the inside of the light source array region A. Therefore, since the reflected light of the surrounding inclined reflecting surface 115a can be used effectively, uniform illumination luminance can be obtained over the entire planar area of the drive region B. However, if the planar range of the drive region B is limited to be within the formation range of the inclined reflecting surface 115a, sufficient illumination luminance uniformity may be obtained. Further, the plane range may be limited to the inside of the inclined reflecting surface 115a. In any case, the in-plane uniformity of the illumination luminance can be appropriately set according to the light emission distribution of the light source 112, the arrangement mode (array density) of the light sources 112, the inclination angle and the formation width of the inclined reflection surface 115a.

  FIG. 7 is an enlarged vertical sectional view showing the internal structure of the light source 112 of the present embodiment. The light source 112 of the present embodiment is composed of an LED (light emitting diode), and a light emitting diode chip 112x, electrodes 112a and 112b conductively connected to the chip 112x via a conductive material 112d such as a wire, and preferably light. A housing 112c made of a reflective (white) resin or the like, and a translucent material 112y made of a transparent resin or the like for sealing the chip 112x are provided. The light source 112 of this embodiment is a so-called top-view type light emitting element, and has an optical axis in the normal direction of the substrate 111 in a state where the bottom portion is conductively connected to a terminal (not shown) on the substrate 111, and the normal line It has a light emission distribution centered on the direction. The light radiation distribution is roughly determined by the light radiation characteristics of the tip 112x and the inclination angle of the inner surface 112z of the housing.

  As the light source 112, the chip 112x has a light emission color of a predetermined hue (for example, red, blue, green, etc.) that emits light in a specific wavelength region in the visible region, and emits light of the same hue. Or may be emitted by changing the emission color of the chip 112x with a phosphor or the like disposed in the light-transmitting material 112y (for example, having a chip having a blue emission color) Or a white light emitting color by a phosphor or the like, or a structure having a predetermined light emitting color as a whole by incorporating a plurality of hue chips. When configuring the backlight of the liquid crystal panel 120, it is usually preferable that the light emission color of the light source 112 be white.

  FIG. 8 is a graph showing the light emission characteristics (light emission distribution) of the light source 112. The light source 112 has an isotropic light emission distribution in a plane orientation around the optical axis, and the light emission angle distribution with respect to the optical axis shows a dispersion curve as shown in FIG. The normal direction of the array plane is a direction in which the light emission angle in FIG. 8 is 90 degrees, and has a light emission intensity peak here, and has a relatively wide light emission distribution on both sides thereof. Note that the peak of the light emission intensity does not need to exactly coincide with the normal direction, and if the range is less than plus or minus 10 degrees with respect to the normal direction, the light emission distribution centering on the normal direction is used. It shall have.

  The half width of the light radiation distribution shown in FIG. 8 is 120 degrees. That is, the emission angle range in which the light intensity equal to or higher than the half value of the peak is obtained is approximately plus or minus 60 degrees with respect to the optical axis. The emission angle range is preferably within a range of 30-80 degrees, and particularly preferably within a range of 50-70 degrees. If the emission angle range is too narrow, the effect of the inclined reflecting surface 115a is reduced, and in order to increase the effect, it is necessary to form the inclined reflecting surface 115a higher, which is contrary to the thinning of the apparatus. In addition, if the emission angle range is too wide, the emission angle of the light emitted from the light emitting portion is increased as a whole, and an efficient illumination effect cannot be obtained, resulting in a decrease in luminance and an increase in power consumption.

  The light emission distribution of the light source 112 is isotropic with respect to the azimuth around the optical axis (the normal of the arrangement plane of the light sources 112, which coincides with the normal of the surface of the substrate 111 in the illustrated example). However, since the light radiation distribution of the light source 112 may not have an isotropic light radiation distribution with respect to the above-mentioned orientation, in this case, in order to ensure the in-plane uniformity of the luminance of the light emitting unit, the light It is preferable to adjust the orientation and orientation of the plurality of light sources 112 with respect to the orientation according to the orientation dependency of the radiation distribution.

  In the present embodiment, as described above, the plurality of light sources 112 are uniformly arranged in the light source array region A. However, the in-plane uniformity of the luminance of the light emitting unit, in particular, the uniformity of the luminance within the plane range of the drive region B. In order to improve performance, it is preferable that the light emission luminance within the plane range of the central portion Ac of the light source array region A is relatively low and the light emission luminance within the plane range of the outer peripheral portion Ao is relatively high. In other words, the light intensity distribution that directly enters the light diffusing plate 116 without passing through the inclined reflecting surface in the light emitting portion may be relatively low at the central portion Ac and relatively high at the outer peripheral portion Ao. preferable.

  As a method of configuring as described above, the light source 112 disposed in the central portion Ac is configured by a light emitting element having a low rated luminance (emission luminance obtained when the same rated voltage or rated current is supplied, the same applies hereinafter). In some cases, the light source 112 disposed on the outer peripheral portion Ao is composed of a light emitting element having a high rated luminance. In some cases, the supply voltage or current to the light source 112 disposed in the central portion Ac is relatively low, and the supply voltage or current to the light source 112 disposed in the outer peripheral portion Ao is relatively high.

  In the above description with reference to FIG. 2, the light source array region A is divided into two parts, the central part Ac and the outer peripheral part Ao. However, light emission is gradually performed from the center toward the outer part in three or more parts. Needless to say, the luminance may be increased. Further, in the above configuration, the corner portion Ax may be configured to have higher emission luminance than the other portions of the outer peripheral portion Ao, or only the corner portion Ax may have higher emission luminance than the central portion Ac. You may comprise as follows.

  With the configuration described above, the uniformity of illumination luminance within the plane range of the drive region B is improved even when the inclined reflecting surface 115a is not present. Therefore, the in-plane uniformity of luminance is further improved by the effect of the inclined reflecting surface 115a. Can be made. In addition, since the amount of light emitted to the periphery of the light source array region A is increased by the above configuration, the amount of light reflected by the inclined reflection surface 115a is also increased, so that the operational effect itself of the inclined reflection surface 115a is further increased. There is an advantage of improvement. In this case, since a certain effect can be obtained even if the height of the inclined reflecting surface 115a is reduced, the thickness of the light emitting portion can be reduced, so that the device can be made thinner.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIG. In this embodiment, the parts not shown and the parts denoted by the same reference numerals are the same as those in the first embodiment, and the description thereof is omitted.

  This embodiment is different from the first embodiment in that a plurality of light sources 112 are arranged in a staggered manner in the light source arrangement region A. Specifically, the light sources 112 included in the illustrated vertical and horizontal light source arrays are alternately arranged at positions shifted by half a period in the vertical and horizontal directions. However, also in the light source array region A, the light sources 112 are arrayed with a uniform distribution density as in the first embodiment.

  The arrangement pattern of the above aspect is such that the light source 112 at the corner Ax is arranged on the outermost peripheral side in the light source arrangement region A so that the light source rows in the outermost vertical and horizontal directions are light sources at both ends in the row. It is set so that the distance between 112x is the largest in the arrangement mode. If it does in this way, the fall of the brightness | luminance of corner Ax can be suppressed and it also becomes possible to heighten the effect by the inclined reflective surface 115a.

[Third Embodiment]
FIG. 4 is a plan view of a light emitting unit according to a third embodiment of the present invention. Also in this embodiment, the portions not shown and the portions denoted by the same reference numerals are the same as those in the first embodiment, and thus the description thereof is omitted.

  The present embodiment is the same as the first embodiment in that the frame body 114 is configured in a rectangular frame shape in plan view, but the inclined reflecting surface 115a at the corner of the frame body 114 'is not refracted. However, it is different in that it is curved in a manner having a predetermined center of curvature inside. With such a configuration, discontinuity between portions belonging to adjacent sides of the inclined reflecting surface 115a is reduced, and the reflecting surface between the portions is continuously formed, so that illumination particularly in the corner Ax and its vicinity is performed. There is an advantage that fluctuations in luminance (discontinuity) can be reduced.

  In this embodiment, the arrangement pattern of the light sources 112 may be different from that of the first embodiment, such as the same arrangement pattern as that of the second embodiment.

[Fourth Embodiment]
FIG. 5 is a plan view of a light emitting unit according to a fourth embodiment of the present invention. Also in this embodiment, the portions not shown and the portions denoted by the same reference numerals are the same as those in the first embodiment, and thus the description thereof is omitted.

  This embodiment is characterized in that the arrangement mode of the light sources 112 in the light source arrangement area A is not uniform unlike the previous embodiments. That is, as in the first embodiment, the light emission luminance within the plane range of the central portion Ac of the light source array region A is relatively low, and the light emission luminance within the plane range of the outer peripheral portion Ao is relatively high. In other words, in order to obtain a configuration in which the light intensity distribution directly incident on the light diffusion plate 116 without passing through the inclined reflection surface is relatively low at the central portion and relatively high at the outer peripheral portion, a plurality of light sources 112 are arranged in such a manner that they are sparse at the central portion Ac and dense at the outer peripheral portion Ao. In the illustrated example, the arrangement interval is gradually reduced from the center toward the outer edge in both the vertical direction and the horizontal direction. However, the arrangement interval may be changed only on any line in the light source arrangement area A such as the vertical direction, the horizontal direction, and the oblique direction.

  In this way, even if the rated luminance and the supply voltage or current of the plurality of light sources 112 are the same, the light intensity distribution reaching the light diffusion plate 116 without passing through the inclined reflection surface 115a as in the first embodiment. It can be made higher on the outer peripheral side than on the central side.

[Fifth Embodiment]
FIG. 6 is a plan view of a light emitting unit according to a fifth embodiment of the present invention. Also in this embodiment, the portions not shown and the portions denoted by the same reference numerals are the same as those in the first embodiment, and thus the description thereof is omitted.

  In the present embodiment, similarly to the fourth embodiment, the light source 112 has an arrangement form in which the light source 112 is sparse at the central portion Ac and dense at the outer peripheral portion Ao, but the arrangement interval of the light sources 112 is uniform in the central portion Ac, Even in the part Ao, the arrangement interval of the light sources 112 is different. In this way, various arrangement patterns can be considered, but it is only necessary that the arrangement pattern is sparse on the central side and dense on the outer peripheral side. Further, the present invention is not limited to a mode in which the coarse / dense intervals are two steps as in this embodiment, and may be a mode having three or more steps.

  Needless to say, another embodiment can be configured by arbitrarily combining the feature points of the respective embodiments described above.

[Electronics]
Finally, an embodiment of an electronic apparatus equipped with the liquid crystal device will be described with reference to FIGS. FIG. 9 is a schematic perspective view showing an appearance of an example of an electronic apparatus according to the invention. The electronic device 200 in the illustrated example is an in-car car navigation system, and includes a main body 210 and a display unit 220 connected to the main body 210. The main body 210 is provided with an operation surface 211 provided with operation buttons and the like, and an introduction port 212 for a recording medium such as a DVD. The liquid crystal device 100 is stored inside the display unit 220, and the display screen of the driving region B of the liquid crystal device 100, that is, the display of the navigation image can be viewed on the display screen 220 a of the display unit 220. ing.

  FIG. 10 is a schematic configuration diagram showing an overall configuration of a control system (display control system) for the liquid crystal device 100 in the electronic apparatus 200. The electronic device 200 includes a display control circuit 290 including a display information output source 291, a display information processing circuit 292, a power supply circuit 293, a timing generator 294, and a light source control circuit 295 that supplies power to the backlight 150. Have. The liquid crystal device 100 includes a liquid crystal panel 110 having the above-described configuration, a drive circuit 150 that drives the liquid crystal panel 110, and the illumination unit 110 that is a backlight. The drive circuit 150 is configured by the integrated circuit chip that is directly mounted on the liquid crystal panel 120. However, in addition to the above-described embodiment, the drive circuit 150 may be an electronic component or circuit pattern formed on the substrate surface of the liquid crystal panel 120, or a semiconductor mounted on a circuit board conductively connected to the liquid crystal panel 120. It can also be configured by an IC chip or a circuit pattern.

  The display information output source 291 includes a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage unit such as a magnetic recording disk or an optical recording disk, and a tuning circuit that tunes and outputs a digital image signal. The display information is supplied to the display information processing circuit 292 in the form of an image signal or the like of a predetermined format based on various clock signals generated by the timing generator 294.

  The display information processing circuit 292 includes various known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information to obtain image information. Are supplied to the drive circuit 150 together with the clock signal CLK. The drive circuit 150 includes a scanning line drive circuit, a signal line drive circuit, and an inspection circuit. The power supply circuit 293 supplies a predetermined voltage to each of the above-described components.

  The light source control circuit 295 supplies power to the light source 112 of the illumination unit 110 based on the voltage supplied from the power supply circuit 293, and controls whether or not the light source is turned on and its luminance based on a predetermined control signal. It has become.

  In addition to the car navigation system shown in FIG. 9, examples of the electronic apparatus according to the present invention include a liquid crystal television, a mobile phone, an electronic watch, an electronic notebook, a calculator, a workstation, a videophone, and a POS terminal. Since the liquid crystal device according to the present invention can be used as a display portion of these various electronic devices, high-quality display characteristics can be obtained.

1 is a schematic longitudinal sectional view of a liquid crystal device according to a first embodiment. The schematic plan view of the light emission part of the illumination unit of 1st Embodiment. The schematic plan view of the light emission part of the illumination unit of 2nd Embodiment. The schematic plan view of the light emission part of the illumination unit of 3rd Embodiment. The schematic plan view of the light emission part of the illumination unit of 4th Embodiment. The schematic plan view of the light emission part of the illumination unit of 5th Embodiment. The expanded longitudinal cross-sectional view of LED which is a light source used for each embodiment. The graph which shows the light radiation distribution of the light source shown in FIG. The schematic perspective view which shows the external appearance of an electronic device. The schematic block diagram of the display control system of an electronic device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Liquid crystal device, 110 ... Illumination unit, 111 ... Board | substrate, 112 ... Light source (LED), 113 ... Reflection layer, 114 ... Frame, 115 ... Reflection layer, 115a ... Inclined reflection surface, 116 ... Light diffusing plate, 120 ... Liquid crystal panel, 121, 122 ... Panel substrate, 124 ... Liquid crystal, A ... Light source array area, Ac ... Central part, Ao ... Outer peripheral part, Ax ... Corner part, B ... Drive area

Claims (9)

A lighting unit comprising: a light source array region in which a plurality of light sources are arranged in a plane on a substrate; and a light diffusing plate disposed on the front side of the light source array region,
The light source has a light radiation distribution centered on the normal direction of the array plane;
An illumination unit comprising an inclined reflection surface surrounding the light source array region on the substrate and inclined outward from the normal direction.   2. The illumination according to claim 1, wherein a light intensity distribution that directly enters the light diffusion plate without passing through the inclined reflection surface is configured to be higher at an outer peripheral portion than a central portion of the light source array region. unit.   3. The light intensity distribution is obtained by increasing the light emission luminance of the light source arranged at the outer peripheral portion than the light emission luminance of the light source arranged at the central portion of the light source arrangement region. Lighting unit.   4. The illumination unit according to claim 2, wherein the light intensity distribution is obtained by increasing an array density of the light sources in the light source array region at an outer peripheral portion rather than a central portion.   5. The lighting unit according to claim 1, wherein the inclined reflecting surface is provided on an inclined inner surface of an integral frame member that surrounds the light source array region. A light source array region in which a plurality of light sources are arranged in a plane on a substrate, a light diffusion plate disposed on the front side of the light source array region, and a transmissive liquid crystal panel disposed on the front side of the light diffusion plate A liquid crystal device comprising:
The light source has a light radiation distribution centered on the normal direction of the array plane;
A liquid crystal device comprising an inclined reflection surface surrounding the light source array region on the substrate and inclined outward from the normal direction.   The light intensity distribution that directly enters the light diffusing plate without passing through the inclined reflection surface is configured to be higher at the outer peripheral portion than at the central portion of the light source array region. Liquid crystal device.   8. The liquid crystal device according to claim 6, wherein a planar range of a driving area of the liquid crystal panel is limited within the light source arrangement area.   An electronic apparatus comprising: the liquid crystal device according to claim 6; and a control driving unit that controls and drives the liquid crystal device.

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