JP2004319458A - Plane lighting device, and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plane lighting device with an array of light emitting elements corresponding to a plurality of colors including at least red, green, and blue colors, that is, a plurality of LEDs (light-emitting diodes) capable of emitting primary colors as a plane light source, and to provide a liquid crystal display achieving high brightness even with a large screen by being equipped with the plane lighting device. <P>SOLUTION: The plane lighting device is at least provided with a plane light source consisting of light-emitting elements corresponding to a plurality of colors including at least the three primary colors of light, a reflecting plate arranged between the light-emitting elements, a base plate on which the light-emitting elements and the reflecting plate are installed, and a diffusing plate located at the head of the light-emitting elements and the reflecting plate. A covering rate of the base plate by the reflecting plate is improved, and the light-emitting elements are aligned, or an irradiation angle to get a maximum light volume of the element corresponding to at least one color is set in accordance with intervals between the reflecting plate and the base plate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a surface illumination device and a liquid crystal display device including the surface illumination device. In particular, the surface illumination device can emit red, green, and blue primary colors of light (LED (Light Emitting Diode)). Alternatively, a liquid crystal display device that achieves high luminance even on a large screen by providing an area light source by arranging LEDs that emit two or more complementary colors has a surface light source. About things.

  As the backlight incorporated in the liquid crystal display device, there are a sidelight type backlight using a cold cathode tube, a direct type backlight, and a sidelight type backlight using an LED. However, the cold cathode tube has problems that a high voltage is required for the inverter and that mercury is contained, and that the color reproduction range is narrow.

Therefore, the use of LEDs as a light source is the mainstream in recent years, and a conventional example is shown below.
The display device 160 of Conventional Example 1 shown in FIG. 23 includes a diffusion plate 1, a light guide plate 18 installed on the back surface of the diffusion plate 1, a red light-emitting LED 7 arranged on a side surface of the light guide plate 18 for lighting, and a blue light emission LED 7. It includes an LED 8 and a green light-emitting LED 9, and mixes light from the light-emitting LED in the light guide plate 18 and diffuses the light with the diffusion plate 1 to realize surface illumination (Patent Document 1).

    In addition, the liquid crystal display device 170 of the second conventional example shown in FIG. 24 includes a liquid crystal panel 13, a prism sheet 11 installed on the back surface of the liquid crystal panel 13, and a first diffusion device installed on the back surface of the prism sheet 11. A board 14 having a plurality of white LEDs 12 mounted on a back surface of the first diffusion plate 14 and a second diffusion plate 15 for taking in external light provided on the back surface of the substrate 4 In addition to supplying white light from a white LED and taking in external light, the liquid crystal panel is illuminated in a planar manner (Patent Document 2).

    Further, the liquid crystal display device 180 of the third conventional example shown in FIG. 25 includes a liquid crystal panel 13, the diffusion plate 1 disposed on the back of the liquid crystal panel, the light guide plate 18 disposed on the back of the diffusion plate 1, and A transmissive plate 16 installed on the back of the light guide plate 18, a red light-emitting LED element 7, a blue light-emitting VFD (vacuum fluorescable display) 17, and a green light-emitting LED element 9 installed on the back of the transparent plate 16; A substrate 4 having a reflector 2 disposed so as to be laid between LED elements, and a side light 20 on a side surface of the light guide plate 18, a red light emitting LED 7, a blue light emitting VFD 17, and a green light emitting LED 9 are monochromatic light It is possible to emit light independently of each other, and to obtain white light, it is characterized in that it is turned on in a short period of time so as to be considered as simultaneous lighting and in order. Patent Document 3, Patent Document 4). Further, in the liquid crystal display device 180 of the third conventional example, the light from the LED passes through the transmission plate 16 and enters the light guide plate 18, where the light is mixed and diffused by the diffusion plate 1. Surface illumination is supplied to the liquid crystal panel 13. Further, the reflection plate 2 returns the light returned from the diffusion plate 1 or the transmission plate 16 to the liquid crystal panel 13 again, and is useful for increasing the luminance of the surface illumination. Here, the reflection plate 2 is provided with a circuit for driving a light emitting element such as a red LED 7 or a wiring for transmitting a signal, as in “Example 2 of LED part and reflection plate structure in Conventional Example 3” shown in FIG. It is installed so as to avoid the provided metal embedded PCB5.

JP-A-2002-341797

JP 2002-311412 A

JP-A-6-018882

JP 2002-258815 A

In the display device 160 of the first conventional example, since the LEDs are arranged at the corners or sides of the light guide plate, there is a problem that the brightness cannot be increased on a large screen.
In addition, in the liquid crystal display device 170 of the second conventional example, a white LED is used. However, since the white LED emits blue light to a yellow phosphor using an LED that emits blue light, white light is generated. There is a problem that the color reproduction range is narrow.

  Further, in the surface illumination of the liquid crystal display device 180 of the above-described conventional example 3, LEDs of different colors are used, and color unevenness and luminance unevenness due to a loss of light amount balance between LEDs emitting different colors cannot be easily overcome. There was a problem.

In order to solve the above problem, a surface lighting device according to claim 1 is
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which a linear light source in which light emitting elements corresponding to each color are arranged in series is arranged in a predetermined order;
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
The surface light source, at least comprising a substrate on which the reflector is installed, and a diffusion plate positioned above the surface light source and the reflector,
The non-light-emitting portion of the light-emitting element is covered by the reflection plate.

Further, in order to solve the above problem, a surface lighting device according to claim 2 is
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light emitting elements corresponding to each color are arranged in series are arranged in a predetermined order;
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
Having a row of convex portions arranged at regular intervals, a substrate on which the surface light source and the reflection plate are installed,
At least a diffusion plate located above the surface light source and the reflection plate,
The linear light source is arranged on the slope of the row-shaped convex portions arranged at regular intervals on the substrate, or on the side surface,
According to the interval between the row-shaped convex portions, and the interval between the diffusion plate and the substrate,
A radiation angle at which a maximum light amount of the light emitting element corresponding to at least one color among a plurality of colors is set by an angle of a slope or a side surface of the row-shaped convex portion.

Further, in order to solve the above problem, a surface lighting device according to claim 3 is
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light-emitting elements corresponding to each color are arranged in series are arranged in a predetermined order and at a constant interval,
Light emission angle correction means in the light emitting portion or on the light emitting portion of the light emitting element,
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
A substrate on which the linear light source and the reflection plate are installed,
At least comprising a linear light source and a diffusion plate positioned above the reflection plate,
According to the interval between the linear light sources, and the interval between the diffusion plate and the substrate,
A radiation angle at which the maximum amount of light is emitted is set by light radiation angle correction means on a light emitting portion of the linear light source corresponding to at least one of the plurality of colors.

In order to solve the above-mentioned problem, a surface lighting device according to claim 4 is
A surface light source in which a light emitting element group in which at least three light emitting elements corresponding to at least three primary colors of light are arranged in proximity to a vertex of a triangle is arranged in a matrix;
At least comprising a substrate on which the light emitting element group is arranged and a diffusion plate positioned above the surface light source,
The light emitting element groups are staggered every other row or every other row so that the positional relationship between the light emitting element groups is in a delta shape,
At the delta-shaped center of gravity and the diamond-shaped center of gravity formed by two delta-shaped elements, the total light quantity of each of the single-color light-emitting elements is 100%, with the average total light quantity calculated from the total light quantity of the single-color light-emitting elements being 100%. In this case, the row spacing, the column spacing, and the arrangement angle of the light emitting element group are adjusted so as to be between 75% and 125%.

According to another aspect of the present invention, there is provided a liquid crystal display device comprising:
At least one of the surface lighting devices described in claim 1, claim 2, claim 3, or claim 4 and a liquid crystal panel are provided.

According to the first and second aspects of the present invention, as described in the first embodiment, it is possible to increase the substrate surface coverage by the reflection plate, and to reduce uneven brightness even when white light is used for the backlight. A prevented surface lighting device can be provided.
Further, according to the third and fourth aspects of the present invention, as described in the second, third and fourth embodiments, even when white light is used for a backlight, color unevenness is prevented. The surface illumination device can be provided.
Further, according to the invention described in claim 5, as described in Embodiment 4, a white light is used for a backlight, but a liquid crystal display device incorporating a surface lighting device that prevents color unevenness or luminance unevenness is provided. Can be provided.

  The surface illuminating device shown in FIG. 1 includes a linear light source in which LED elements 3 are continuously arranged, a reflection plate 2 filling the space between the LED elements 3, and an aluminum plate or the like on which the LED elements 3 and the reflection plate 2 are installed. It is composed of a substrate 4 which is made of a material and also serves as a heat radiating plate, and a transparent diffuser plate 1 which is located above and is transparent. Here, the “reflector 2 buried between the LED elements 3” is defined as a cross-sectional view and a plan view illustrating “a structural example 1-1 of the LED portion and the reflector in Example 1” in FIG. Of the LED element 3 and the reflector 2 disposed on the metal-embedded PCB 5 on which the non-light emitting portion and the wiring or circuit for driving the LED element 3 are disposed. Further, as shown in the cross-sectional view and the plan view illustrating “the structural example 1-2 of the LED portion and the reflector in the first embodiment” in FIG. 3, the light emitting portion of the LED element 3 is fitted to the reflector 2. The reflective plate 2 may be arranged such that a through hole is formed and a portion other than the LED light emitting portion is covered by the reflective plate 2.

  By arranging the reflection plate 2 as shown in FIGS. 2 and 3, the surface area coverage of the reflection plate 2 can be made 94% or more as shown in Table 1, so that the brightness unevenness can be greatly improved. effective.

ここで、表１は「従来例３におけるＬＥＤ部分と反射板構造例２」と「実施例３におけるＬＥＤ部分と反射板構造例１−１」及び「実施例３におけるＬＥＤ部分と反射構造例１−２」について、反射板が、基板表面をカバーする率を計算するとともに、拡散板透過光量と発光量の比率である光利用効率も計算し、計算結果を比較できるようにまとめたものである。なお、前記の表面カバー率及び前記光利用効率を計算するにあたっては、ＬＥＤ素子のレンズ直径６ｍｍ、反射板の幅２４ｍｍ、ＬＥＤ素子からなる線状光源のラインピッチ１２０ｍｍ、拡散板ゲイン０．８の条件で行った。また、反射板の材質としてはアルミ板反射板、白色ポリエステル（発泡させるとともに、散乱材が混入されているもの）、銀蒸着ポリエステルが考えられるが、光利用効率の計算では、白色ポリエステルの場合として計算した。

Here, Table 1 shows “Example 2 of LED part and reflector structure in Conventional Example 3”, “Example 1-1 of LED part and reflector structure in Example 3”, and “Example 1 of LED part and reflector structure in Example 3”. With respect to “−2”, the ratio at which the reflector covers the substrate surface is calculated, and the light use efficiency, which is the ratio between the amount of light transmitted through the diffuser and the amount of light emitted, is calculated, and the calculation results are summarized so that the results can be compared. . In calculating the surface coverage and the light use efficiency, the lens diameter of the LED element was 6 mm, the width of the reflector was 24 mm, the line pitch of the linear light source made of the LED element was 120 mm, and the diffusion plate gain was 0.8. Performed under conditions. In addition, as a material of the reflection plate, an aluminum plate reflection plate, white polyester (which is foamed and a scattering material is mixed), and silver-evaporated polyester can be considered. Calculated.

  The surface illumination device shown in FIG. 4 includes a linear light source in which LED elements 3 each having a prism 6 attached to a light-emitting surface are continuously arranged, a reflection plate 2 buried between the LED elements 3, an LED element 3 and a reflection plate. 2, a substrate 4 made of a material such as an aluminum plate and also serving as a heat radiator, and a transparent diffuser 1 that is located above and diffuses light. Here, the “reflector 2 that fills the space between the LED elements 3” in FIG. 4 simply refers to the reflector 2 that fills the space between the LED elements 3 as in the conventional example, but is shown in FIGS. 2 and 3. As described above, the reflection plate 2 that fills between the LED elements may be used.

  By attaching the prism 6 to the light emitting surface of the LED element 3, the emission angle of the peak light quantity of each LED element 3 can be set arbitrarily. Note that a mirror or a scattering plate can be used similarly to the prism 6. Therefore, a light emission pattern having a light emission peak angle of 45 degrees or more as shown in FIG. 5A can be realized, and as shown in FIG. 5B, light from a plurality of linear light sources is superimposed. There is an effect that a constant light amount can be obtained regardless of the light source position. Therefore, an effect is obtained in which the color unevenness is not visually recognized even in the color unevenness visual test as shown in FIG. Here, θp shown in FIG. 5 indicates a radiation angle at which the light amount of the LED element becomes maximum, φ0 indicates a light amount at a radiation angle of 0 °, and φp indicates a peak light amount. FIG. 5 (a) shows the relationship between the radiation angle and the light quantity of the LED element, and FIG. 5 (b) shows that the distance from the substrate 4 to the diffusion plate 1 is H, plus 2H starting from the light source, The light amount just below the diffuser in the range of minus 2H is shown. On the other hand, in FIG. 6, the horizontal axis represents the peak light amount angle of the LED element, and the vertical axis represents the peak light amount of the LED element reduced by the light amount at a radiation angle of 0 degree. As for the surface light source composed of the LED element which adjusted the light amount and the peak light amount emission angle by processing such as the conversion process, the white circle is a surface light source where color unevenness was not visually recognized, and the black circle is a surface light source where color unevenness was visually recognized. It is shown together with the optical properties of the LED element.

  In FIG. 4, the emission angle at which the LED element 3 has the maximum luminance is adjusted by providing the prism 6 on the LED element 3, but may be adjusted by other light emission angle adjusting means. Means such as deformation of the light emitting surface of the element 3 and change of the mounting angle of the light emitting element may be used. Further, the light emission angle adjusting means need not be provided on the LED element 3 but may be provided in the LED element 3.

  The surface lighting device shown in FIG. 7 includes a linear light source in which the LED elements 3 are continuously arranged, a reflection plate 2 filling the space between the LED elements 3, and an aluminum plate or the like on which the LED elements 3 and the reflection plate 2 are installed. It is composed of a substrate 4 which is made of a material and also serves as a heat radiator, a heat sink 19 for transmitting heat from the LED elements 3 to the heat radiator, and a transparent diffuser plate 1 which is located above and diffuses light. The line light source is provided on a slope from the substrate 4 on which the projections on the rows protrude. Here, the “reflector 2 buried between the LED elements 3” refers to the reflector 2 arranged as shown in FIG. 2 and FIG. 3, but the reflector 2 arranged as shown in FIG. It may be.

  By arranging the LED elements 3 on the slope, it is possible to set the emission angle of the peak light amount to an arbitrary angle when the LED elements 3 arranged continuously on both sides of the slope are viewed as a line light source. Therefore, a light emission pattern having a light emission peak angle of 45 degrees or more as shown in FIG. 5 can be realized. According to the color unevenness visual test shown in FIG. 6, the effect of suppressing color unevenness can be suppressed. There is.

  The surface lighting device shown in FIG. 8 includes a linear light source in which the LED elements 3 are continuously arranged, a heat sink 19 that transmits heat from the LED elements 3 to a heat radiating plate, and a reflecting plate 2 that fills between the linear light sources. It is composed of a substrate 4 which is made of a material such as an aluminum plate, on which the LED element 3 and the reflection plate 2 are installed, and which also serves as a heat radiating plate, and a diffusion plate 1 which is located above and is transparent but diffuses light. The light sources are installed on both sides of a vertical plate protruding from the substrate 4. Here, the “reflector 2 that fills the space between the linear light sources” refers to the reflector 2 installed as shown in FIGS. 2 and 3, which is the reflector 2 arranged as shown in FIG. You may.

  By arranging the LED elements 3 continuously on the side surfaces of the above-mentioned vertical plate, when the continuously arranged LED elements 3 are viewed as linear light sources, the emission angle of the peak light amount is set to 90 degrees as shown in FIG. It is the same as what was done. Therefore, as shown in FIG. 6, according to the color unevenness visual recognition test, there is an effect that visual recognition of color unevenness is further suppressed.

  The surface illumination device shown in FIG. 10 has a green line light source G-LED 35 in which green LED elements having a prism 6 attached to a light emitting surface are continuously arranged, and a blue LED element having a prism 6 attached to a light emitting surface. The blue line light source B-LED 36 arranged side by side, the red line light source R-LED 34 lined up continuously with red LED elements having the prism 6 attached to the light emitting surface, and the drawing between the line light sources are shown in the drawing. And a substrate 4 which is also made of a material such as an aluminum plate on which the primary color LED elements and the reflection plate 2 are installed, and which also serves as a heat sink, and a transparent but light-diffusing diffuser The prism 1 is attached to the light emitting surface of each primary color LED element, so that the maximum light emitting angle of each color LED element can be changed. Further, a height from the substrate 4 constituting the surface illumination device shown in FIG. 10 to the diffusion plate 1 is H, a red line light source R-LED 34 indicated by a symbol R, a blue line light source B-LED 36 indicated by a symbol B, When the repetition period of the linear light source is L, which is a set of the green line light source G-LED 35 indicated by the symbol G, the following formula is satisfied.

(Equation 1)
L ≦ 2H × tan (maximum emission angle of LED element)
According to the surface illumination device of FIG. 10, the maximum light emission angle cannot be set to 45 degrees or more as shown in FIG. 9A, and the distance H between the diffusion plate 1 and the substrate 4 becomes H as shown in FIG. = (1/2) × L, the distance between the diffusion plate 1 and the substrate 4 is set as shown in Equation 1, even if a constant amount of light cannot be obtained directly below the diffusion plate 1. There is an effect that a constant amount of light can be obtained directly under the area 1 and color unevenness can be suppressed. Here, θp shown in FIG. 9 indicates a radiation angle at which the light amount of the LED element becomes maximum, φ0 indicates a light amount at a radiation angle of 0 °, and φp indicates a peak light amount. FIG. 9A shows the relationship between the radiation angle and the light amount of the LED element, and FIG. 9B shows the height from the substrate 4 to the diffusion plate 1 as H, with the light source as the starting point. The light amount immediately below the diffusion plate in the range of plus 2H and minus 2H is shown.

  By the way, in the surface illumination device shown in FIG. 10, the emission angle at which the maximum brightness of the LED element of each color is adjusted by providing the prism 6 on the LED element of each color, but adjustment is performed by other light emission angle adjusting means. For example, it may be a means such as deformation of the light emitting surface of the LED element of each color, change of the mounting angle of the light emitting element, or the like. Further, the light emission angle adjusting means does not need to be provided on each color LED element, but may be provided in each color LED element. Although red, blue, and green are selected as a combination of a plurality of colors, similar effects can be obtained even when intermediate colors such as cyan, magenta, and yellow are further added.

  The surface illumination device shown in FIG. 11 includes a green line light source G-LED 35 in which a green LED element having a prism 6 attached to a light emitting surface is continuously arranged, and a blue LED element having a prism 6 attached to a light emitting surface. The blue line light source B-LED 36 arranged in a row and the red line light source R-LED 34 in which a red LED element in which the prism 6 is attached to the light emitting surface are successively arranged, and the drawing between the line light sources is described in the drawing. A reflection plate 2 which is not provided, a substrate 4 which is made of a material such as an aluminum plate on which the primary color LED elements and the reflection plate 2 are provided, and which also serves as a heat radiating plate, and which is located above and is transparent but diffuses light. It is composed of a diffusion plate 1 and has a feature in that a prism 6 is attached to a light emitting surface of each primary color LED element so that the maximum light emitting angle of the LED element 3 can be changed. Further, a height from the substrate 4 constituting the surface illumination device shown in FIG. 10 to the diffusion plate 1 is H, a red line light source R-LED 34 indicated by a symbol R, a blue line light source B-LED 36 indicated by a symbol B, When the repetition period of the linear light emitting source is L, which is a set of the green line light source LED 35 indicated by the symbol G, the height H and the period L are adjusted, and the in-plane light amount is averaged in the plane. When the light amount is set to 100%, the light amount falls within a range of 80% to 125%.

Therefore, according to the surface illumination device shown in FIG. 11, for example, when φ0 is the light amount at the radiation angle θ, φ2 is the light amount at the radiation angle θ, and φ1 is the light amount at the radiation angle θ ′, the green line light source G -LED
The light amount just above 35 is expressed as (φ0 + 2 × φ2 × COS3θ), and it is possible to suppress the variation of the in-plane light amount expressed as the light amount (2 × φ1 × COS3θ ′) just above the center of the two rows of green light source G-LEDs 35. As a result, there is an effect that the light amount becomes almost constant immediately below the diffusion plate 1 and color unevenness is suppressed. Although red, blue, and green are selected as a combination of a plurality of colors, similar effects can be obtained even when intermediate colors such as cyan, magenta, and yellow are further added.

  The surface illuminating device shown in FIG. 12 includes a line light source in which LED elements 3 are continuously arranged, a reflector 2 not shown in the drawing in which the line light sources are buried, and an aluminum in which the LED element 3 and the reflector 2 are installed. It is composed of a substrate 4 which is a material such as a plate and also serves as a heat radiating plate, and a transparent diffuser plate 1 located above which diffuses light. Here, the diffusion plate is a transparent acrylic resin plate provided with irregularities for scattering light on the surface thereof, or a transparent acrylic resin containing light scattering particles and formed into a plate shape. is there. Therefore, the diffuser constituting the surface illumination device shown in FIG. 11 has a gain of about 1.5 to 0.8 by adjusting the degree of surface irregularities, the size of scattering particles, and the thickness of the diffuser. It is characterized by having done. Here, the gain of the diffuser means a gain represented by the following equation, assuming that transmitted light having a vertical luminance of B candela is obtained when incident light of L lux is input vertically.

(Equation 2)
Gain = π × (B / L)
According to the above-described surface lighting device, since the light from each of the line light sources is appropriately scattered by the diffusion plate, light from the adjacent line light sources having different colors is uniformly mixed. Therefore, as shown in FIG. 13, the lower the gain, the greater the light scattering. Therefore, even if there is a large variation in the amount of light immediately below the diffusion plate due to the linear light source, the effect of improving the visibility is achieved. . Here, in FIG. 13, the horizontal axis represents the in-plane light amount variation width of a single color on the lower surface of the diffusion plate (refers to the in-plane light amount variation width when the average in-plane light amount is 100%), and the vertical axis visually confirms. This is a result of investigating the visibility of diffusing plates of different types as characteristics (meaning the ratio of those who do not mind color unevenness among 10 test subjects). In addition, those shown by white circles and long broken lines show the visibility for the diffusion plate having a gain of about 1.5, and those shown by black circles and solid lines show the visibility for the diffusion plate having a gain of about 1.0. , Squares and short dashed lines indicate the visibility with respect to the diffuser having a gain of about 0.8, and the lower the gain of the diffuser, the greater the visibility even when the in-plane light amount fluctuation width is large. To ensure that.

  The surface lighting device 100 shown in FIG. 14 is a group in which a red light-emitting LED 7, a blue light-emitting LED 8, and a green light-emitting LED 9 are linearly arranged within a unit length L1, and the group is further linearly spaced at intervals L1. A plurality of linear light sources, a reflector 2 not shown in the drawing that fills the space between the linear light sources, and a material such as an aluminum plate on which the above-described primary color light emitting LEDs and the reflector 2 are installed, and a heat sink is also used. It is characterized by comprising a substrate 4 which also serves as a light source and a diffusion plate 1 which is located above and is transparent but diffuses light. The order of arrangement of the primary color light-emitting LEDs is constant in any linear light source. The linear light sources are arranged at intervals of D1 to form a surface light source. The height between the linear light source and the diffusion plate 1 is H1.

  According to the surface illumination device 100 shown in FIG. 14, since attention is paid to the primary color LEDs of the same color, they are arranged so as to form a quadrangle, so that the fluctuation width of the in-plane light amount of a single color can be reduced, and the color of each primary color is synthesized. There is an effect that even white light can be obtained. Although red, blue, and green are selected as a combination of a plurality of colors, similar effects can be obtained even when intermediate colors such as cyan, magenta, and yellow are further added.

  The surface lighting device 110 shown in FIG. 15 is a group in which a red light-emitting LED 7, a blue light-emitting LED 8, and a green light-emitting LED 9 are linearly arranged within a unit length L1, and the group is further linearly spaced at intervals L1. A plurality of linear light sources, a reflector 2 not shown in the drawing that fills the space between the linear light sources, and a material such as an aluminum plate on which the above-described primary color light emitting LEDs and the reflector 2 are installed, and a heat sink is also used. It is characterized by comprising a substrate 4 which also serves as a light source and a diffusion plate 1 which is located above and is transparent but diffuses light. Further, a linear light source in which a group in which primary color light emitting LEDs are arranged in the order of red, green, and blue is linearly arranged, and a line in which a group in which primary color light emitting LEDs are arranged in the order of blue, red, and green are linearly arranged. A planar light source is formed by alternately arranging linear light sources at an interval D1, and a triangle is formed when attention is paid to primary color LEDs of the same color, and the height between the linear light source and the diffusion plate 1 is H1. . Further, when defining the midpoint C between the adjacent linear light sources A and B as shown in FIG. 15, the position where the extension line of the maximum light emission direction of the LED constituting the arbitrary linear light source reaches the diffusion plate 1. The height H1, the interval D1, and the maximum light emission direction of the LED element are adjusted so that E exceeds the midpoint C.

  According to the surface illuminating device 110 shown in FIG. 15, when attention is paid to the primary color LEDs of the same color, since the triangle is formed, it is possible to reduce the fluctuation width of the in-plane light amount of a single color, and to suppress luminance unevenness. When the midpoint C is defined between the adjacent linear light sources A and B as shown in FIG. 15, the position where the extension line of the maximum light emission direction of the LED constituting the arbitrary linear light source reaches the diffusion plate 1. By adjusting the height H1, the interval D1, and the maximum light amount radiation direction of the LED element so that E exceeds the middle point C, the in-plane light amount fluctuation width can also be reduced, and as shown in FIG. As the position E approaches the position directly above the adjacent light source B, the visibility is increased. Here, FIG. 16 shows the visibility on the vertical axis and the position of point E on the horizontal axis. The point E is drawn from the linear light source A of interest c to a position directly above the adjacent linear light source B. 4 shows the visibility when the maximum light emission angle of the LED in the light source A is adjusted. Although red, blue, and green are selected as a combination of a plurality of colors that become white by mixing light, colors having a complementary color relationship may be selected. For example, a similar effect can be obtained with a combination of yellow and blue. Play.

  FIG. 17 shows the arrangement of the light emitting element groups in the surface lighting device 120. The surface lighting device 120 has a red light emitting LED 7, a blue light emitting LED 8, and a green light emitting LED 9 arranged in close proximity to each other and forms a delta group (hereinafter referred to as “Δ”). Group)), and is not shown in the drawing in which the surface light source formed by further arranging the above Δ group in a delta arrangement (hereinafter referred to as “Δ arrangement”) and the primary color light emitting LEDs constituting the surface light source are filled. A reflecting plate 2; a substrate 4 which is a material such as an aluminum plate on which the primary color light emitting LEDs and the reflecting plate 2 are installed; And a plate 1. Further, by adjusting the row interval D1, the column interval D2, and the arrangement angle θ between the Δ groups, the light amount of each primary color LED at the center 1 and the center 2 of the blank area where the primary color light emitting LED elements are not arranged is adjusted. When comparing the sums, when the average value of the sum of the light amounts is set to 100%, the sum is within the range of 75% to 125%. Here, the center 1 refers to the center of gravity of three LED Δ groups arranged in Δ, and the center 2 refers to the center of gravity of four LED Δ groups arranged in diamond and arranged in two Δ arrangements. By the way, in the case where attention is paid to the two LED Δ groups facing each other when the LED Δ groups are arranged Δ, it is preferable that the light emitting elements of different colors face each other. This is because the feature relating to the sum of light amounts can be easily achieved.

  When arranging the LED groups so that the sum of the light amounts of the primary color LEDs is within the range of 75% to 125%, the light amount variation between the single primary color LED elements and the light amount variation between the primary color LED elements Was almost nonexistent. However, even if such variations exist, by adding means such as selecting the LED elements and adjusting the current supplied to the LED elements, the light quantity variation between the single primary color LED elements and the Can hardly vary.

According to the surface lighting device shown in FIG. 17, each primary color LED is arranged in close proximity to form a Δ group, and further, by arranging the Δ groups in Δ, it is possible to arrange LED elements without bias in the plane, When attention is paid to a single primary color, a uniform light amount can be obtained in a plane, and there is an effect of suppressing luminance unevenness.
Further, in the central portion of the Δ arrangement where the LED elements are not arranged, the sum of the light amounts of the respective primary color LEDs, that is, the sum of the light amounts of the red LEDs, the sum of the light amounts of the blue LEDs, placed at the top of the Δ arrangement, Comparing the sum of the light amounts of the green LEDs, assuming that the average value of the sum of the light amounts is 100%, by adjusting the row interval D1, the column interval D2, and the arrangement angle θ, the total light amount of each primary color LED becomes 75%. Since the LED Δ group is arranged so as to be within the range of 125%, there is an effect of suppressing color unevenness when light is mixed. In addition, in the center 2 portion of the diamond arrangement where no LED elements are arranged, the same operation as in the center 1 portion is performed so that the sum of the light amounts of the primary color LEDs is in the range of 75% to 125%. The arrangement of the groups has the effect of further suppressing color unevenness when light is mixed. Although red, blue, and green are selected as a combination of a plurality of colors that become white by mixing light, colors having a complementary color relationship may be selected. For example, a similar effect can be obtained with a combination of yellow and blue. Play.

  FIG. 18 shows the arrangement of the light emitting element groups in the surface lighting device 130. The surface lighting device 130 has a red light emitting LED 7, a blue light emitting LED 8, and a green light emitting LED 9 arranged in close proximity to form a delta group (hereinafter referred to as “Δ”). ), And a drawing in which a plurality of the above Δ groups are arranged in a quadrangular shape (hereinafter, referred to as “square arrangement”), and the space between the primary color light emitting LEDs constituting the surface light source is filled. And a substrate 4, which is a material such as an aluminum plate, on which the above-described primary color light emitting LEDs and the reflective plate 2 are installed, and also serves as a heat sink, and which is transparent, And a diffusion plate 1 for diffusing the light. Further, by adjusting the row interval D1, column interval D2, and arrangement angle θ between the Δ groups, the total sum of the light amounts of the primary color LEDs is compared at the center 1 of the blank area where the primary color light emitting LED elements are not disposed. Then, it is characterized in that it is in the range of 75% to 125%. Here, the center 1 refers to the center of gravity of the four LED Δ groups arranged in a square. By the way, in the case where attention is paid to two LED Δ groups facing each other when the LED Δ groups are arranged in a square arrangement, it is preferable that light emitting elements of different colors face each other. This is because the feature relating to the sum of light amounts can be easily achieved.

  When arranging the LED groups so that the sum of the light amounts of the primary color LEDs is within the range of 75% to 125%, the light amount variation between the single primary color LED elements and the light amount variation between the primary color LED elements Was almost nonexistent. However, even if such variations exist, by adding means such as selecting the LED elements and adjusting the current supplied to the LED elements, the light quantity variation between the single primary color LED elements and the Can hardly vary.

According to the surface illumination device shown in FIG. 18, each primary color LED is arranged in close proximity to form a Δ group, and further, by arranging the Δ groups in a square, it is possible to arrange LED elements without bias in the plane, When attention is paid to a single primary color, a uniform light amount can be obtained in a plane, and there is an effect of suppressing luminance unevenness.
Further, in one center of the square arrangement where the LED elements are not arranged, the sum of the light amounts of the primary color LEDs placed at the top of the square arrangement, that is, the sum of the light amounts of the red LEDs, the sum of the light amounts of the blue LEDs, Comparing the sum of the light amounts of the green LEDs, assuming that the average value of the sum of the light amounts is 100%, by adjusting the row interval D1, the column interval D2, and the arrangement angle θ, the total light amount of each primary color LED becomes 75%. Since the LED Δ group is arranged so as to be within the range of 125%, there is an effect of suppressing color unevenness when light is mixed. Although red, blue, and green are selected as a combination of a plurality of colors, a similar effect can be obtained by further adding an intermediate color such as cyan, magenta, or yellow.

  FIG. 19 shows the arrangement of the light emitting elements in the surface lighting device 140. The surface lighting device 140 has four LED elements including a red light emitting LED 7, a blue light emitting LED 8, and a green light emitting LED 9 arranged in close proximity. A square light source (hereinafter, referred to as a “quadrangular group”), and a surface light source configured by further forming the square group in a delta arrangement (hereinafter, referred to as a “Δ arrangement”); A reflection plate 2 not shown in the drawing in which the primary color light emitting LEDs are filled, a substrate 4 on which the above-described primary color light emitting LEDs and the reflection plate 2 are installed and made of a material such as an aluminum plate and also serving as a heat radiating plate; It is characterized by comprising a transparent plate located thereon and a diffusion plate 1 for diffusing light. Further, by adjusting the row interval D1, the column interval D2, and the arrangement angle θ between the Δ groups, the light amount of each primary color LED at the center 1 and the center 2 of the blank area where the primary color light emitting LED elements are not arranged is adjusted. When comparing the sums, when the average value of the sum of the light amounts is set to 100%, the sum is within the range of 75% to 125%. Here, the center 1 refers to the center of gravity of the three LED square groups arranged in Δ, and the center 2 refers to the center of gravity of four LED square groups arranged in diamond and arranged in two Δ arrangements. . By the way, in the case where attention is paid to the two LED Δ groups facing each other when the LED Δ groups are arranged Δ, it is preferable that the light emitting elements of different colors face each other. This is because the feature relating to the sum of light amounts can be easily achieved.

  When arranging the LED square groups so that the total light amount of each primary color LED is within the range of 75% to 125%, the light amount variation between the single primary color LED elements and the light amount variation between the primary color LED elements It was assumed that there was almost no variation in light quantity. However, even if such variations exist, by adding means such as selecting the LED elements and adjusting the current supplied to the LED elements, the light quantity variation between the single primary color LED elements and the Can hardly vary.

According to the surface lighting device shown in FIG. 19, the primary color LEDs are arranged in close proximity to form a square group, and furthermore, by arranging the square group in Δ, it is possible to arrange LED elements without bias in the plane. When attention is paid to a single primary color, a uniform light amount can be obtained in a plane, and there is an effect of suppressing luminance unevenness.
Further, in the central portion of the Δ arrangement where the LED elements are not arranged, the sum of the light amounts of the respective primary color LEDs, that is, the sum of the light amounts of the red LEDs, the sum of the light amounts of the blue LEDs, placed at the top of the Δ arrangement, Comparing the sum of the light amounts of the green LEDs, assuming that the average value of the sum of the light amounts is 100%, by adjusting the row interval D1, the column interval D2, and the arrangement angle θ, the total light amount of each primary color LED becomes 75%. Since the LED square groups are arranged so as to be within the range of 125%, there is an effect of suppressing color unevenness when light is mixed. In addition, in the center 2 portion of the diamond arrangement where no LED elements are arranged, the same operation as in the center 1 portion is performed so that the sum of the light amounts of the respective primary color LEDs is within the range of 75% to 125%. Since the square groups are arranged, there is an effect of further suppressing color unevenness when light is mixed. Although red, blue, and green are selected as a combination of a plurality of colors, a similar effect can be obtained by further adding an intermediate color such as cyan, magenta, or yellow.

  FIG. 20 shows the arrangement of the light emitting elements in the surface lighting device 120. The surface lighting device 150 has four LED elements including a red light emitting LED 7, a blue light emitting LED 8, and a green light emitting LED 9 arranged in close proximity. A surface light source comprising a square group (hereinafter referred to as a “square group”), a plurality of the square groups arranged in a square shape (hereinafter referred to as a “square arrangement”), and a surface light source A reflector 2 not shown in the drawing, which fills the space between the primary color light emitting LEDs, and a substrate 4 on which the above primary color light emitting LEDs and the reflector 2 are installed, which is made of a material such as an aluminum plate and also serves as a heat sink. And a diffuser plate 1 that is located above and is transparent but diffuses light. Further, by adjusting the row interval D1, column interval D2, and arrangement angle θ between the square groups, the total light amount of each primary color LED at the center 1 of the blank region where the primary color light emitting LED elements are not arranged is adjusted. When compared, it is characterized by being in the range of 75% to 125%. Here, the center 1 refers to the center of gravity of the three square LED groups arranged in a square. By the way, in the case where attention is paid to two LED Δ groups facing each other when the LED Δ groups are arranged in a square arrangement, it is preferable that light emitting elements of different colors face each other. This is because the feature relating to the sum of light amounts can be easily achieved.

  When arranging the LED square groups so that the total light amount of each primary color LED is within the range of 75% to 125%, the light amount variation between the single primary color LED elements and the light amount variation between the primary color LED elements It was assumed that there was almost no variation in light quantity. However, even if such variations exist, by adding means such as selecting the LED elements and adjusting the current supplied to the LED elements, the light quantity variation between the single primary color LED elements and the Can hardly vary.

According to the surface lighting device shown in FIG. 20, each primary color LED is arranged in close proximity to form a square group, and furthermore, by arranging the square group in a square, it is possible to arrange LED elements without bias in the plane. When attention is paid to a single primary color, a uniform light amount can be obtained in a plane, and there is an effect of suppressing luminance unevenness.
Further, at the center of the square arrangement where the LED elements are not arranged, the sum of the light amounts of the primary color LEDs placed at the top of the square arrangement, that is, the sum of the light amounts of the red LEDs, the sum of the light amounts of the blue LEDs, Comparing the sum of the light amounts of the green LEDs, assuming that the average value of the sum of the light amounts is 100%, by adjusting the row interval D1, the column interval D2, and the arrangement angle θ, the total light amount of each primary color LED becomes 75%. Since the LED Δ group is arranged so as to be within the range of 125%, there is an effect of suppressing color unevenness when light is mixed. Although red, blue, and green are selected as a combination of a plurality of colors, a similar effect can be obtained by further adding an intermediate color such as cyan, magenta, or yellow.

  By the way, in the surface lighting devices 120 to 150 shown in FIGS. 17 to 20, the light emitting element group is composed of three to four light emitting elements, but may be composed of more light emitting elements. . The description of the color types of the light-emitting elements constituting the light-emitting element group has been described in terms of the three primary colors, blue, red, and green, but combinations of blue, red, green, cyan, magenta, yellow, and the like. In this case, the light emitting element group may be configured so as to be arranged close to the vertices of a hexagon or more polygon.

  Next, as shown in the sectional view of FIG. 21, the liquid crystal display device 190 shown in FIG. 22 includes a display unit including the backlight and the liquid crystal panel 13 in the surface illumination device 30 shown in FIG. And a power supply 42, and configured to receive and operate the input signal 43. The surface lighting device 30 further includes a resistor 31 for adjusting a current flowing through a red LED constituting the linear light source R-LED 34. , A resistor 32 for adjusting the current flowing to the green LED forming the linear light source G-LED 35 and a resistor 33 for adjusting the current flowing to the blue LED forming the linear light source B-LED 36. Since the surface illumination device shown in FIG. 1 has little luminance unevenness and is bright, the liquid crystal display device has an effect of obtaining a uniform and bright display.

  In the above-described liquid crystal display device 190, the surface illumination device 30 shown in FIG. 1 is used for the backlight, but FIGS. 4, 7, 8, 10, 11, 12, 14, and FIG. Liquid crystal display devices using the surface illumination devices 40 to 150 shown in FIGS. 15, 17, 18, 19, and 20 can also be produced. In that case, the effects of each surface lighting device can be obtained by the liquid crystal display device.

(Appendix 1)
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which a linear light source in which light emitting elements corresponding to each color are arranged in series is arranged in a predetermined order;
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
The surface light source, at least comprising a substrate on which the reflector is installed, and a diffusion plate positioned above the surface light source and the reflector,
The non-light-emitting portion of the light-emitting element is covered with the reflector, and the surface lighting device is characterized in that:

(Appendix 2)
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light-emitting elements corresponding to each color are arranged in series are arranged in a predetermined order and at a constant interval,
A first reflector laid so as to fill a space between the light emitting elements constituting the linear light source;
A second reflector having a through-hole into which a light emitting portion of the light emitting element can be fitted, the surface light source, the first reflector, and a substrate on which the second reflector is provided;
The surface light source, at least comprising a diffusion plate positioned above the first reflection plate and the second reflection plate,
The non-light-emitting portion of the light-emitting element is covered by the second reflection plate.

(Appendix 3)
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light emitting elements corresponding to each color are arranged in series are arranged in a predetermined order;
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
Having a row of convex portions arranged at regular intervals, a substrate on which the surface light source and the reflection plate are installed,
At least a diffusion plate located above the surface light source and the reflection plate,
The linear light source is arranged on the slope of the row-shaped convex portions arranged at regular intervals on the substrate, or on the side surface,
According to the interval between the row-shaped convex portions, and the interval between the diffusion plate and the substrate,
A surface lighting device, wherein a radiation angle at which a maximum light amount of the light-emitting element corresponding to at least one of a plurality of colors is set by an angle of a slope or a side surface of the row-shaped convex portion.

(Appendix 4)
At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light-emitting elements corresponding to each color are arranged in series are arranged in a predetermined order and at a constant interval,
Light emission angle correction means in the light emitting portion or on the light emitting portion of the light emitting element,
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
A substrate on which the linear light source and the reflection plate are installed,
At least comprising a linear light source and a diffusion plate positioned above the reflection plate,
According to the interval between the linear light sources, and the interval between the diffusion plate and the substrate,
A surface lighting device, wherein a radiation angle at which a maximum light amount is set is set by light radiation angle correction means on a light emitting portion of the linear light source corresponding to at least one of a plurality of colors.

(Appendix 5)
When the installation interval of the linear light source corresponding to one color described in Supplementary Note 3 or 4 is a fixed value L, and the interval between the diffuser plate and the plane on which the linear light source is installed is a fixed value H,
L ≦ 2 × H × tan (radiation angle at which the maximum light amount of the linear light source is reached)
The surface illumination device according to Supplementary Note 3 or 4, wherein a radiation angle at which a maximum light amount of the linear light source is set so as to satisfy the following relationship.

(Appendix 6)
A surface light source in which a light emitting element group in which three light emitting elements corresponding to three primary colors of light are arranged close to the apex of a triangle is arranged in a matrix;
At least comprising a substrate on which the light emitting element group is arranged and a diffusion plate positioned above the surface light source,
The light emitting element groups are staggered every other row or every other row so that the positional relationship between the light emitting element groups is in a delta shape,
At the delta-shaped center of gravity and the diamond-shaped center of gravity formed by two delta-shaped elements, the total light quantity of each of the single-color light-emitting elements is 100%, with the average total light quantity calculated from the total light quantity of the single-color light-emitting elements being 100%. Wherein the row spacing, the column spacing and the arrangement angle of the light emitting element group are adjusted so as to be between 75% and 125%.

(Appendix 7)
A linear light source in which light emitting element groups in which three light emitting elements corresponding to three primary colors of light are arranged in series and close to each other are arranged in a row;
At least comprising a light emitting angle correction unit in the light emitting unit or on the light emitting unit of the light emitting element, a substrate on which the light emitting element group is arranged, and a diffusion plate positioned above the surface light source,
A plurality of rows of the linear light sources are arranged as a surface light source,
The point where the maximum radiation direction of the light emitting element and the diffuser intersect, corrected by the light emission angle correcting means in the light emitting portion of the light emitting element constituting the linear light source of interest or on the light emitting portion,
A planar lighting device, wherein a maximum emission angle of the light emitting element is corrected so as to exceed a midpoint of the linear light source adjacent to the linear light source of interest.

(Appendix 8)
At least one of the surface lighting devices according to any one of supplementary notes 1 to 7,
A liquid crystal display device comprising: a liquid crystal panel.

Example 1 (Surface lighting device 30: direct-type backlight structure) Structure example 1-1 of LED portion and reflector in embodiment 1 Structure Example 1-2 of LED Portion and Reflector in Embodiment 1 Example 2 (surface lighting device 40) LED light emission pattern (emission angle indicating peak light intensity is 45 degrees or more) Peak light intensity radiation angle, radiation intensity and visibility Example 3 (Surface lighting device 50) Example 4 (surface lighting device 60) LED light emission pattern (emission angle indicating peak light intensity is less than 45 degrees) Example 5 (surface lighting device 70) Example 6 (surface lighting device 80) Example 7 (surface lighting device 90) Light intensity variation and visibility on the bottom of the diffuser Example 8 (Surface lighting device 100) Example 9 (surface lighting device 110) Relationship between point E position and visibility Example 10 (arrangement of light emitting elements in surface illumination device 120) Example 11 (arrangement of light emitting elements in surface illumination device 130) Example 12 (arrangement of light emitting elements in surface lighting device 140) Example 13 (arrangement of light emitting elements in surface illumination device 150) Example 14 (Cross-sectional view of display section of liquid crystal display device 190) Example 14 (Liquid crystal display device 190) Conventional example 1 (display device 160) Conventional example 2 (liquid crystal display device 170) Conventional example 3 (liquid crystal display device 180) Structural example 2 of LED part and reflector in conventional example 3

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Diffusion plate 2 Reflection plate 3 LED element 4 Substrate 5 Metal embedded PCB
6 Prism 7 Red light emitting LED
8 Blue LED
9 Green LED
10 scattering pattern 11 prism sheet 12 white LED
13 liquid crystal panel 14 first diffusion plate 15 second diffusion plate 16 transmission plate 17 blue light emitting VFD
Reference Signs List 18 light guide plate 19 heat sink 20 side light 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 surface illumination device 160 display device 170, 180, 190 liquid crystal display device

Claims (5)

At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which a linear light source in which light emitting elements corresponding to each color are arranged in series is arranged in a predetermined order;
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
The surface light source, at least comprising a substrate on which the reflector is installed, and a diffusion plate positioned above the surface light source and the reflector,
The non-light-emitting portion of the light-emitting element is covered with the reflector, and the surface lighting device is characterized in that: At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light emitting elements corresponding to each color are arranged in series are arranged in a predetermined order;
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
Having a row of convex portions arranged at regular intervals, a substrate on which the surface light source and the reflection plate are installed,
At least a diffusion plate located above the surface light source and the reflection plate,
The linear light source is arranged on the slope of the row-shaped convex portions arranged at regular intervals on the substrate, or on the side surface,
According to the interval between the row-shaped convex portions, and the interval between the diffusion plate and the substrate,
A surface lighting device, wherein a radiation angle at which a maximum light amount of the light-emitting element corresponding to at least one of a plurality of colors is set by an angle of a slope or a side surface of the row-shaped convex portion. At least, among a combination of a plurality of colors including three primary colors of light, a surface light source in which linear light sources in which light-emitting elements corresponding to each color are arranged in series are arranged in a predetermined order and at a constant interval,
Light emission angle correction means in the light emitting portion or on the light emitting portion of the light emitting element,
A reflector laid so as to fill the space between the light-emitting elements constituting the linear light source,
A substrate on which the linear light source and the reflection plate are installed,
At least comprising a linear light source and a diffusion plate positioned above the reflection plate,
According to the interval between the linear light sources, and the interval between the diffusion plate and the substrate,
A surface lighting device, wherein a radiation angle at which a maximum light amount is set is set by light radiation angle correction means on a light emitting portion of the linear light source corresponding to at least one of a plurality of colors. A surface light source in which a light emitting element group in which three light emitting elements corresponding to three primary colors of light are arranged close to the apex of a triangle is arranged in a matrix;
At least comprising a substrate on which the light emitting element group is arranged and a diffusion plate positioned above the surface light source,
The light emitting element groups are staggered every other row or every other row so that the positional relationship between the light emitting element groups is in a delta shape,
At the delta-shaped center of gravity and the diamond-shaped center of gravity formed by two delta-shaped elements, the total light quantity of each of the single-color light-emitting elements is 100%, with the average total light quantity calculated from the total light quantity of the single-color light-emitting elements being 100%. Wherein the row spacing, the column spacing and the arrangement angle of the light emitting element group are adjusted so as to be between 75% and 125%. A liquid crystal display device comprising at least one of the surface lighting devices according to claim 1 and a liquid crystal panel.

Images