JP2008311026A - Surface light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface light source device in which primary light sources can be mixed at a short distance even if arrayed at a wide pitch distance and which has excellent brightness well-proportionality (brightness uniformity). <P>SOLUTION: The surface light source device includes a plurality of primary light sources 2 arrayed in one direction, a reflector plate 4 positioned below light-emitting parts thereof, barrier ribs 5 positioned on the reflector plate, formed so that partitioned chambers 2' corresponding to respective primary light sources 2 are formed, and made of members for reflecting at least one part of coming light, and a diffusion plate 6 arranged above the barrier ribs and the partitioned chambers. The arrayed pitch distance L (mm) of the primary light source 2, the height H (mm) of the barrier rib 5, and the distance D (mm) between the barrier rib and the diffusion plate satisfy H≥0.25L+10-D and 0≤D≤0.25L. On the diffusion plate 6, a diffusion film 7 and a prism sheet 8 are arranged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface light source device, and more particularly to a direct light source or edge light type surface light source device with improved brightness uniformity (brightness uniformity).

  As a surface light source device for illuminating a display panel such as a liquid crystal panel, a surface light source device using a cold cathode tube (CCFL) or a light emitting diode (LED) is known.

  As these surface light source devices, there are an edge light type in which a primary light source is disposed adjacent to an end face of a light guide plate, and a direct type in which a diffuser plate and a prism lens sheet are disposed above the primary light source.

  In particular, surface light source devices used for liquid crystal televisions or the like are mainly direct surface light source devices with high light utilization efficiency in order to use a surface light source that uniformly illuminates a large screen with high brightness.

  With regard to a direct surface light source device using CCFL as a primary light source, it has been studied to reduce the number of CCFLs for the purpose of power consumption and cost reduction. However, by reducing the number of CCFLs, the distance between CCFLs becomes longer, and a lamp image is remarkably generated.

  For this reason, in the direct-type CCFL surface light source device, it is necessary to ensure a sufficient distance between the CCFL and the diffusion plate, or to use an optical member such as a diffusion plate having a higher diffusion degree.

  However, increasing the distance between the CCFL and the diffusion plate increases the thickness of the display. Further, when an optical member having a higher diffusivity is used, there is a risk of lowering the luminance.

  On the other hand, as a direct light source surface light source device using LEDs as primary light sources, RGB-LEDs using three types of LED chips emitting monochromatic light of red (R), green (G) and blue (B) as a set There is a surface light source device. This RGB-LED surface light source device produces white light by mixing monochromatic light emitted from three types of monochromatic LED chips emitting monochromatic light of R, G, and B.

  Such an RGB-LED surface light source device produces white light by mixing three types of monochromatic light. Therefore, in order to produce white light having no color unevenness, a mixing distance for mixing monochromatic light is set. It is necessary to ensure enough, and the thickness of the display becomes large.

Therefore, in order to mix monochromatic light at a short distance, a method of arranging each color LED at a narrow pitch (Patent Document 1, Patent Document 2), a method of arranging a light control plate directly above the LED (Patent Document 3), etc. An applied RGB-LED surface light source device has been proposed.
JP 2006-189665 A JP 2005-339822 A JP 2006-59606 A

  However, in the surface light source device described in Patent Document 1, it is necessary to arrange a large number of LEDs on a substrate in order to improve luminance uniformity, and there is a problem of power consumption, and in arranging the LEDs on a large substrate. Yield and cost issues arise.

  Moreover, in the surface light source device described in Patent Document 2, it is necessary to arrange the LED light sources densely in order to improve luminance uniformity, which causes an increase in LED cost and a problem of power consumption.

  In addition, when the LED light sources are roughly arranged in these surface light source devices, it is necessary to dispose the LED light source and the diffusion plate at a large distance, and there is a problem that the total thickness of the surface light source device is increased.

  In the surface light source device described in Patent Document 3, since a light control plate using printing dots is used, a reduction in luminance due to a decrease in light utilization efficiency becomes a problem.

  The present invention has been made to solve such problems, and in a direct surface light source device including a plurality of primary light sources, even if the primary light sources are arranged at a wide pitch, they can be mixed at a short distance. An object of the present invention is to provide a surface light source device with good brightness uniformity (brightness uniformity).

According to the present invention,
A plurality of primary light sources arranged in at least one direction;
A reflector positioned below the light emitting portion of the plurality of primary light sources;
A partition wall formed on the reflector and formed to form a compartment corresponding to each of the plurality of primary light sources, and made of a member that reflects at least a part of the incoming light;
A diffusion plate disposed above the partition and the compartment;
A surface light source device comprising:
Is provided.

  According to such a configuration, even when a combination of three types of monochromatic LED chips that emit R, G, and B monochromatic light is used as the primary light source, the monochromatic light emitted from the monochromatic LED chip is used. It is possible to perform efficient mixing by reflecting at least a portion multiple times including reflection on the partition wall surface (that is, multiple reflection). Moreover, since multiple surface reflections including reflection on the partition wall surface can provide a surface light source device with good luminance uniformity in each compartment, the primary light source can be arranged roughly, and the cost of the primary light source and Power consumption can be reduced.

In one aspect of the present invention, an arrangement pitch distance L (mm) of the plurality of primary light sources, a partition wall height H (mm), and a partition wall-to-diffusion plate distance D (mm) are expressed by the following formula (1): And formula (2)
H ≧ 0.25L + 10−D (1)
0 ≦ D ≦ 0.25L (2)
Meet.

  According to such a configuration, a surface light source device with good luminance uniformity can be obtained without increasing the total thickness of the surface light source device (partition wall height + [distance between the partition wall and the diffusion plate]).

  In one aspect of the present invention, one or more light deflection elements are disposed between the partition and the diffusion plate.

  According to such a configuration, the light emitted from the primary light source is deflected and reflected by the light deflecting element, so that the light is more mixed, and the brightness unevenness in each compartment is reduced to achieve a surface with good brightness uniformity. A light source device can be obtained.

  In one aspect of the present invention, the partition wall has a notch formed in the upper portion between at least one set of the compartments adjacent to each other.

  According to such a configuration, light leaks through the notches into the adjacent compartments, so that luminance unevenness between the compartments can be reduced and a surface light source device with good luminance uniformity can be obtained.

  In one aspect of the present invention, the shape of the compartment opening formed above the compartment is a square, a rectangle or a hexagon.

  In one aspect of the present invention, the plurality of primary light sources are arranged in at least two directions, and the partition walls are formed in a lattice shape.

  In one aspect of the present invention, each of the plurality of primary light sources includes at least one light emitting diode.

  In one aspect of the present invention, each of the plurality of primary light sources includes at least one cold cathode tube.

  In one aspect of the present invention, a diffusion film is disposed above the diffusion plate, and a light deflection element is disposed above the diffusion film.

  According to such a configuration, a high-luminance surface light source device can be obtained.

Moreover, according to the present invention,
A light guide plate having an entrance end face and an exit face, guiding light introduced through the entrance end face and emitting the light from the exit face;
An end surface light source device composed of the surface light source device, disposed adjacent to the incident end surface of the light guide plate;
Including
A surface light source device, wherein light emitted from the end surface light source device is incident on an incident end surface of the light guide;
Is provided.

  According to such a configuration, light with good luminance uniformity is emitted from the end surface light source device as described above, and this is incident on the incident end surface of the light guide plate, so that bright lines and dark lines in the vicinity of the incident end surface of the light guide plate, etc. Occurrence can be suppressed and surface light source quality can be improved.

  In one aspect of the present invention, a diffusion film is disposed above the exit surface of the light guide plate, and a light deflection element is disposed above the diffusion film.

  According to the surface light source device of the present invention, the brightness uniformity can be improved without increasing the thickness or increasing the number of primary light sources.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the second and subsequent embodiments, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof will be simplified or omitted. Further, the configuration of each drawing of each embodiment is shown differently from an actual dimensional ratio for the sake of simplicity. In the present specification, the primary light source may be simply referred to as a light source.

[First Embodiment]
A surface light source device 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 is a cross-sectional view of a direct-type surface light source device 1, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  As shown in FIGS. 1 and 2, in the surface light source device 1, when viewed downward from above, that is, in plan view, a plurality of primary light sources 2 are regularly arranged in two vertical and horizontal directions. The reflection surface of the reflection plate 4 is arranged in a region other than 2. The primary light source 2 is disposed on the substrate 3 located under the reflector 4 and has a light emitting unit that emits light. The reflector 4 is located below the light emitting part of the primary light source 2. That is, the primary light source 2 extends through an opening formed in the reflecting plate. On the reflection plate 4, a lattice-like partition wall 5 is formed extending vertically and horizontally in plan view. A partition 2 ′ corresponding to each of the plurality of primary light sources 2 is formed by the partition wall 5. A diffusion plate 6 is disposed above the partition wall 5 and the compartment 2 '.

  In this embodiment, the primary light source 2 is a white light emitting diode (LED) light source, and is of a Lambertian emission type having a wide light emission light distribution with respect to the emission surface of the LED light source. An example of such an LED is LUXEON-LXHL-PW01 (Lumbar Shan type) manufactured by Philips Lumileds lighting Company. Each of the primary light sources 2 made of monochromatic LEDs is of a 1 W high current drive type, for example, and is driven with a current of about 300 mA.

  The substrates 3 on which the primary light sources 2 are arranged are provided for each group of the primary light sources 2 arranged in a row in the horizontal direction. Each substrate 3 has a vertical and horizontal dimension of about 10 mm in length × about 320 mm in width and a thickness of About 2 mm (t). A group of six primary light sources 2 is arranged on the substrate 3 with a pitch distance L = 40 mm. Eight such substrates 3 are arranged in parallel in the vertical direction at a pitch distance of 40 mm. That is, 48 primary light sources 2 are arranged at a pitch distance of 40 mm in each of the vertical and horizontal directions. The pitch distance L is preferably 5 to 200 mm in consideration of the number of primary light sources and the balance of luminance.

  Here, the substrate 3 is formed of an aluminum material having excellent heat dissipation in order to efficiently dissipate the heat generated by the LEDs 2, and a heat dissipation sheet (not shown) is provided on the back surface (lower surface) of the substrate 3. A heat radiating fin (not shown) is attached via the.

  The reflection plate 4 located above the substrate 3 has an opening at a position corresponding to the primary light source 2, and the primary light source 2 extends above the upper surface of the reflection plate 4 through the opening. The light emitting part of the primary light source 2 is located above the upper surface of the reflector 4.

  In the present embodiment, the reflection plate 4 is formed of a light diffusion reflection sheet (RF188 manufactured by Tsujiden, thickness 188 μm, spectral reflectance of light having a wavelength of 600 nm, 95.5%). Here, the reflection plate 4 has a function of diffusing and reflecting the return light reflected by the partition walls 5 and the diffusion plate 6 out of the light emitted from the primary light source 2 and emitting it again upward or obliquely.

  The partition wall 5 in the present embodiment has a lattice shape corresponding to each light source 2, and has a rectangular opening (compartment opening) corresponding to each light source and the compartment in the upper part thereof. That is, the partition wall 5 is surrounded by a partition wall portion in which each light source and the compartment extend in the vertical direction and the horizontal direction in a plan view. In addition, the partition wall 5 is formed so as to extend vertically upward with respect to the reflection plate 4.

  The partition wall 5 is made of a member that reflects at least a part of incoming light, and is made of, for example, a reflecting member that reflects light or a semi-transmissive diffusing member that semi-transmits light.

  Examples of the reflecting member include a light diffusing and reflecting sheet containing a white pigment, a light diffusing and reflecting sheet having foam inside, and a specular reflecting sheet having a metal such as silver or aluminum deposited on the surface thereof. Here, the light emitted from each primary light source 2 is mixed by multiple reflection including reflection at the partition wall portion surrounding each primary light source 2 and extending in the vertical direction and the horizontal direction, and as a result, at each compartment opening. Brightness uniformity, that is, brightness uniformity in each compartment 2 'is improved, and a surface light source device with high brightness uniformity can be obtained.

  Examples of the semi-transmissive diffusing member include a milky white light diffusing sheet containing diffusing fine particles inside or on the resin surface. Here, a part of the transmitted light emitted from the light source 2 and transmitted through the semi-transmissive partition wall is mixed with the light reflected by the partition wall surrounding the compartment in the adjacent compartment 2 ′, Thus, it is possible to improve the luminance uniformity at the opening of the adjacent compartments, that is, the luminance uniformity at the adjacent compartments 2 '.

  In the present embodiment, the partition wall 5 has a vertical and horizontal pitch distance P = 40 mm, a height H = 25 mm, and has a total of 48 divisions (i.e., eight divisions in the vertical direction and six divisions in the horizontal direction so that the opening shape is square). The number of side wall openings and the number of compartments 2 'were 48).

  Here, the partition walls 5 were formed of a light diffusive reflection sheet (RF188 manufactured by Tsujiden, thickness 188 μm, spectral reflectance of light having a wavelength of 600 nm 95.5%). The thickness of the partition wall 5 is preferably 50 to 500 μm. A preferable range of the pitch distance P of the partition walls 5 is the same as the pitch distance L of the primary light source 2.

  The primary light source 2 is arranged at the center of the compartment opening, that is, the center of the compartment 2 'in plan view. Or when using what consists of several LED as the primary light source 2, it is preferable to arrange | position these symmetrically with respect to the center of compartment opening, ie, the center of compartment 2 '. By adopting such a configuration, it is possible to improve the luminance uniformity in the compartment opening, that is, the luminance uniformity in the compartment 2 '. When a primary light source 2 comprising a plurality of LEDs is used, the pitch distance L of the primary light source 2 indicates the distance between the centers of the compartments 2 '.

  In the present embodiment, the shape of the compartment opening, that is, the shape of the compartment 2 ′ is a regular rectangular shape, but the shape of the compartment opening, that is, the compartment 2 ′ may be rectangular or hexagonal. When the shape of the compartment opening or compartment 2 'is hexagonal, a plurality of primary light sources 2 are arranged in three directions.

In the present embodiment, the arrangement pitch distance L (mm) of the primary light sources 2, the height H (mm) of the partition walls 5, and the distance D (mm) between the partition walls and the diffusion plate are expressed by the following formula (1) and Formula (2)
H ≧ 0.25L + 10−D (1)
0 ≦ D ≦ 0.25L (2)
Meet.

  When D exceeds 0.25 times L, the luminance of the surface light source device decreases, and the total thickness of the surface light source device (partition wall height + [distance between partition walls and diffusion plate]) increases, which is not preferable. On the other hand, if H is less than 0.25L + 10−D, the luminance uniformity of the surface light source device decreases, which is not preferable. H is preferably 60 mm or less.

  By satisfying the above formulas (1) and (2), the luminance uniformity in each compartment becomes good, the luminance uniformity in the adjacent compartments becomes good, and the arrangement pitch distance P of the primary light sources 2 is improved. Even if is large, it is possible to obtain a surface light source device having good luminance uniformity as a whole.

  The diffuser plate 6 disposed in front (above) of the partition wall 5 and the compartment 2 ′ is emitted from the primary light source 2 and is directly or indirectly after reflection or transmission by the reflector 4 and the partition wall 5. The light emitted upward through it is diffused and made uniform. The diffusing plate 6 is made of the transparent resin in a transparent resin such as polymethyl methacrylate resin (PMMA), polystyrene resin (PSt), polycarbonate resin (PC), methacryl-styrene copolymer resin (MS), cyclic polyolefin resin (COP). Is a light diffusing plate formed by uniformly dispersing diffusing particles made of inorganic or organic materials having different refractive indexes.

  Here, as for the optical characteristics of the diffusion plate 6, the transmittance is 50% or more and 92% or less, and more preferably 70% or more and 92% or less. The haze at that time is 20% or more and 98% or less, and more preferably 50% or more and 98% or less.

  The diffusion plate 6 is disposed, for example, 5 mm away from the upper end of the partition wall 5. With such a configuration, the light emitted from the adjacent compartment openings, that is, the compartments 2 'is mixed in the space between the diffusion plate 6 and the upper end of the partition wall 5, and a surface light source with higher luminance uniformity. Can be obtained.

  In this embodiment, the diffusion plate 6 is an acrylic diffusion plate (made by Mitsubishi Rayon, trade name Acrylite NA88, transmittance 63%, haze 90%) having a thickness of about 320 × 240 mm (15-inch screen). Is a rectangular plate.

  In the present embodiment, a diffusion film 7 is disposed in front of the diffusion plate 6. The diffusion film 7 isotropically condenses or diffuses the light emitted from the diffusion plate 6. A prism sheet 8 is disposed in front of the diffusion film 7. The prism sheet 8 deflects the light emitted from the diffusion film 7 in a substantially normal direction of the surface light source device (a substantially normal direction of the diffusion plate 6).

  In the present embodiment, the total thickness of the surface light source device 1 (distance from the reflecting plate 4 to the diffusion plate 6) is about 33 mm, and the total opening surface size of the surface light source device (the size of the region corresponding to the entire compartment opening). Has a rectangular shape with a length and width of about 320 × 240 mm (equivalent to a 15-inch screen).

  With such a configuration, the light emitted from the primary light source 2 is subjected to multiple reflections including reflection on the partition wall surface, whereby a surface light source device with high luminance uniformity in each compartment opening, that is, each compartment 2 ′. Can be obtained.

  Furthermore, even if the pitch distance L of the primary light sources 2 is large and the primary light sources are roughly arranged, a surface light source device with good luminance uniformity can be obtained without increasing the thickness of the surface light source device.

[Second Embodiment]
A surface light source device 20 according to a second embodiment of the present invention will be described with reference to FIGS. 3 is a cross-sectional view of the surface light source device 20, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

  As shown in FIGS. 3 and 4, the surface light source device 20 has substantially the same configuration as the surface light source device 1 of the first embodiment except for the primary light source 21.

  Each of the primary light sources 21 includes three types of single-color LEDs, that is, a red LED 21r, a green LED 21g, and a blue LED 21b. In the present embodiment, the LED light source 21 is a side emitter type having a light intensity peak at an emission angle of ± 80 ° with respect to the normal direction of the surface light source device. An example of such an LED light source is LUXEON (side emitter type) manufactured by Philips Lumileds lighting Company. Since the side emitter type LED light source 21 emits light mainly toward the partition wall surface, mixing by multiple reflection proceeds and the luminance of the surface light source device can be made more uniform.

  In the present embodiment, the primary light source 21 includes one red LED (LUXEON-LXHL-DH01) 21r, two green LEDs (LUXEON-LXHL-DM01) 21g, and one blue LED (LUXEON-LXHL-DR01). ) 21b. The LED light sources 21r, 21g, and 21b are 1 W high current drive types and are driven with a current of about 300 mA. Here, the drive current is only a guideline, and in practice, the drive current is appropriately controlled by a sensor and a controller in order to achieve a good white color.

  The substrates 3 on which the primary light sources 21 are arranged are provided for each group of the primary light sources 21 arranged in a row in the horizontal direction. Each substrate 3 has a vertical and horizontal dimension of about 25 mm in length × about 320 mm in width and a thickness of About 2 mm. A group of six primary light sources 21 is arranged on the substrate 3 with a pitch distance L = 40 mm. Eight such substrates 3 are arranged in parallel in the vertical direction at a pitch distance of 40 mm. That is, 48 primary light sources 2 are arranged at a pitch distance of 40 mm in each of the vertical and horizontal directions.

  The primary light source 21 is disposed at the center of the compartment opening, that is, the center of the compartment 2 'in plan view. In the present embodiment, the center of each color-LED light source 21 (21r, 21g, 21b) is located at a distance of about 6 mm from the center of the side wall opening in plan view, the two green LEDs 21g are diagonally located, and red. The LED 21r and the blue LED 21b are positioned diagonally. That is, each primary light source 21 is constituted by four color-LED light sources 21r, 21g, and 21b as a unit, and the center of the unit (corresponding to the center of the side wall opening, that is, the center of the compartment 2 ') is set to each primary light source. As the center of 21, 6 units (total number of LEDs: 24) are arranged in a line on each substrate 3 at a pitch distance L = 40 mm, and the substrates 3 are arranged in parallel at a pitch distance of 40 mm in 8 rows. .

  In the present embodiment, the partition walls 5 are formed such that the vertical and horizontal pitch distances P = 40 mm, the height H = 25 mm, and the shape of the openings is square. The compartment 2 ′ was formed in a total of 48 (that is, the number of side wall openings was 48), 8 in the vertical direction and 6 in the horizontal direction. Here, the partition 5 was formed with a light diffusive reflection sheet (RF188 manufactured by Tsujiden, thickness 188 μm, spectral reflectance 95.5% / 600 nm).

  In this embodiment, the partition upper part is provided with the notch 5a which consists of the recessed part formed in the substantially circular arc shape for every part corresponding to each compartment opening. In this embodiment, the notch 5a has an arc shape with a depth of 10 mm from the highest part of the partition wall 5, a radius of 25 mm, and a chord length of 40 mm. The depth of the notch 5a is preferably 0.1 to 0.5 times the height H of the partition wall.

  FIG. 5 is a view of a model in which the primary light sources 21 are arranged in the four compartments 2 ′ partitioned by the partition walls 5 as viewed from above, and FIG. 6 is along the line VI-VI in FIG. 5. It is sectional drawing.

  As shown in FIG. 4, the shape of the upper part of the partition wall may be a shape having a flat tip as shown in the first embodiment (as shown in the uppermost part of FIG. 4), but as in the second embodiment. The tip may have a shape having a notch formed by a substantially arc-shaped recess corresponding to each compartment 2 ′ (second one shown from the top in FIG. 4), or two compartments whose tips are adjacent to each other. It may be a shape having a notch formed of a substantially arc-shaped recess extending across the top (shown third from the top in FIG. 4), or a notch with a tip having a serrated shape (the bottom one in FIG. 4) It may be.

  In this manner, the partition wall 5 has a notch 5a in the upper portion between at least one pair of the compartments 2 ′ so that a part of the light emitted from the primary light source 21 is cut. It leaks into the adjacent compartment 2 'from the notch 5a. Thus, the light emitted from the adjacent compartments is mixed, and the luminance distribution in the adjacent compartment opening, that is, the luminance distribution in the adjacent compartment can be made uniform, and a surface light source with higher luminance uniformity can be obtained. Can be obtained.

  In the present embodiment, the diffusion plate 6 is disposed 5 mm away from the highest portion of the partition wall 5. In the present embodiment, the total thickness of the surface light source device 20 (distance from the reflecting plate 4 to the diffuser plate 6) is about 33 mm, and the overall opening surface size of the surface light source device is about 320 × 240 mm (15 inch screen). Is equivalent to a rectangular shape.

  With such a configuration, the same effect as in the first embodiment can be obtained, and even if a unit composed of each RGB color LED is arranged as the primary light source 21, the light emitted from the primary light source 21 is reflected on the partition wall surface. By performing multiple reflection including reflection, it is possible to easily mix colors of monochromatic lights in each compartment opening, that is, each compartment 2 ′. Further, by providing a recess in the upper part of the partition wall, uneven luminance in adjacent compartment openings, that is, adjacent compartments 2 'can be reduced, and a surface light source device with good brightness uniformity can be obtained.

[Third Embodiment]
A surface light source device 30 according to a third embodiment of the present invention will be described with reference to FIGS. 7 is a cross-sectional view of the surface light source device 30, and FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG.

  The surface light source device 30 has substantially the same configuration as the surface light source device 1 of the first embodiment except for the primary light source 32 and the light deflection element 31.

  As shown in FIG. 7, the primary light source 32 of the surface light source device 30 is in the form of an LED module including a plurality of LED light sources (LED chips) 33. As shown in FIG. 8, the plurality of LED light sources 33 are three types of top-emitting type monochromatic LED light sources, that is, a red LED chip (emission center wavelength: 625 nm) 33r, a green LED chip (emission center wavelength: 525 nm) 33g. And it is comprised from the blue LED chip (light emission center wavelength: 460 nm) 33b. In the present embodiment, the LED light source 33 is composed of three red LED chips 33r, five green LED chips 33g, and two blue LED chips 33b. Each single color LED chip 33r, 33g, 33b is a 0.38 mm square high current drive type, and is driven with a current of about 50 mA. Here, the drive current is only a guideline, and in practice, the drive current is appropriately controlled by a sensor and a controller in order to achieve a good white color.

  In the present embodiment, in the LED module 32, the LED light source 33 is mounted on the bottom surface of the recess 35 a formed on the top surface of the substrate 3. The recess 35a has a truncated cone shape whose diameter increases toward the upper side (front side), and the side wall surface is a reflecting surface. In the present embodiment, the size of the recess 35a is set such that the opening diameter is 5.6 mm, the bottom diameter is 4.8 mm, and the depth is 0.5 mm.

  The substrate 3 is manufactured by applying an insulating layer on the surface of an aluminum base material, attaching a conductor such as a copper foil thereon, and processing the conductor into an electrode / wiring by a photolithography process. Thereafter, a recess 35a is formed on the upper surface by embossing. Further, the electrode / wiring portion is plated with silver having a high reflectance, the LED chip 33 is fixed to the recess 35a, and the LED chip 33 and the electrode on the substrate 3 are connected by a bonding wire. After mounting the LED chip 33, the sealing resin 34 is injected into the recess 35 a to seal the LED chip 33, thereby obtaining the LED module 32.

  In this embodiment, as the sealing resin 34, a sealing resin in which silica spherical particles having an average particle diameter of 2 μ are dispersed substantially uniformly at 10 wt% is used. Since the silica itself is transparent and the average particle diameter is about 2 μm, the light from the LED chip 33 can be diffused without loss and without color. Moreover, since the silica particle diameter is about 2 μm, the sealing resin 34 easily flows, and the sealing resin 34 can be easily filled in a region to be sealed. Furthermore, since silica is very stable thermally, the durability of the surface light source device 30 is not lowered by the silica particles.

  In order to improve the dispersion of light, as a diffusing agent to be contained in the sealing resin 34, silica particles treated with phenylsilane, bubbles having a diameter of several hundreds nm to several μm order diameter, and the like may be used. By doing so, the light emitted from the LED module 32 is diffused in all directions, the component of the light that is multiply reflected by the partition wall surface is increased, and a surface light source with better luminance uniformity can be obtained.

  The substrates 3 on which the LED modules 32 are arranged are provided for each group of the LED modules 32 arranged in a row in the horizontal direction. Each substrate 3 has a vertical and horizontal dimension of about 25 mm in length × about 320 mm in width and a thickness of About 2 mm. A group of six LED modules 32 is arranged on the substrate 3 with a pitch distance L = 40 mm. Eight such substrates 3 are arranged in parallel in the vertical direction at a pitch distance of 40 mm. That is, 48 LED modules 32 are arranged at a pitch distance of 40 mm in each of the vertical and horizontal directions.

  In the present embodiment, the partition walls 5 are formed so that the vertical and horizontal pitch distances P = 40 mm, the height H = 15 mm, and the opening shape is square. The compartment 2 ′ was formed in a total of 48 (that is, the number of side wall openings was 48), 8 in the vertical direction and 6 in the horizontal direction.

  In the present embodiment, one or more light deflection elements 31 are arranged above the partition wall 5. That is, the light deflection element 31 is disposed between the partition wall 5 and the diffusion plate 6. As the light deflection element 31, a prism lens sheet in which a large number of columnar triangular prisms are arranged in parallel, a cross prism lens sheet in which a two-dimensional slope is formed, a cylindrical lens sheet, a microlens sheet, a triangular pyramid or four Examples thereof include a corner cube lens sheet such as a pyramid, and an isotropic condensing sheet in which beads are coated on the surface.

  The lens shape of the light deflection element 31 is formed on one side or both sides of a transparent substrate such as polyethylene terephthalate (PET) and polycarbonate resin (PC). Here, the light deflection element 31 may be arranged such that the lens forming surface faces either upward (diffuser plate 6 side) or downward (LED module 32 side).

  FIG. 9 is an enlarged plan view of the light deflection element 31 in the present embodiment. The light deflection element 31 is a corner cube lens sheet in which triangular pyramids with an apex angle of 90 ° and L = 30 μm are arranged, and is arranged directly above the partition wall 5 with a size of about 320 × 240 mm and a lens surface facing upward. .

  According to such a configuration, light incident on the light deflection element 31 from the LED module 32 side from the normal direction of the surface light source device can be deflected and retroreflected by the light deflection element 31. As a result, the amount of light directly above the LED module 32 can be controlled, and this reduces the light source image (eyeball defect) generated by the high brightness directly above the LED module 32 when the LED module 32 is roughly arranged. can do.

  As the diffusing plate 6 disposed above the light deflection element 31, the same diffusing plate as in the first embodiment was used. The diffusing plate 6 was disposed 5 mm away from the light deflection element 31.

  In the present embodiment, the total thickness of the surface light source device 30 (distance from the reflecting plate 4 to the diffuser plate 6) is about 25 mm, and the total opening surface size of the surface light source device is about 320 × 240 mm (15 inch screen). Is equivalent to a rectangular shape.

  According to the surface light source device 30 of the third embodiment as described above, the same effect as that of the first embodiment can be obtained, and further, by arranging the light deflection element, the normal line of the surface light source device with respect to the light deflection element. By deflecting and retroreflecting light incident from the direction, the amount of light directly above the primary light source can be controlled, the primary light source image (eyeball defect) can be reduced, and a surface light source device with high luminance uniformity can be obtained.

[Fourth Embodiment]
A surface light source device 40 according to a fourth embodiment of the present invention will be described with reference to FIGS. 10 and 11. 10 is a cross-sectional view of the surface light source device 40, and FIG. 11 is a cross-sectional view taken along the line XX of FIG.

  The surface light source device 40 has substantially the same configuration as the surface light source device 30 of the third embodiment except for the primary light source 42.

  In the surface light source device 40, as shown in FIGS. 10 and 11, a plurality of primary light sources 42 are arranged in parallel on the reflector 4, and the compartment 2 ′ is partitioned by each primary light source 42. A partition wall 5 is provided so as to be formed. Above the partition wall 5, the light deflection element 44 and the diffusion plate 6 are arranged.

  The primary light source 42 of the surface light source device 40 is formed of a cold cathode tube (CCFL) and is disposed above the reflection plate 4. In this embodiment, CCFLs having a tube diameter of 4 mm and a tube length of 420 mm are arranged in parallel with a pitch distance of about 30 mm and a distance from the CCFL tube wall to the reflector 4 of 2 mm. The opening of the partition 5 is formed corresponding to each CCFL.

  In the present embodiment, the size of the entire surface of the surface light source device is a rectangular shape having a length and width of about 320 × 420 mm (corresponding to a 20-inch screen), and the pitch in the direction perpendicular to the longitudinal direction of the CCFL is within this total opening size. A partition wall 5 having a distance P = 30 mm and a height H = 10 mm was formed, and a vertically divided compartment 10 was formed so that the shape of the side wall opening was a rectangle. A CCFL extending in the lateral direction is arranged in each compartment. Here, the partition 5 was formed of a light diffusive reflection sheet (RF188 manufactured by Tsujiden, thickness 188 μm, spectral reflectance of light having a wavelength of 600 nm, 95.5%).

  In the present embodiment, the light deflection element 44 is the same as the light deflection element 31 of the third embodiment and has a size of 320 mm × 420 mm in length and breadth, and this light deflection element 44 is disposed immediately above the partition wall 5. did.

  The diffusing plate 6 disposed above the light deflecting element 44 is the same as that of the first embodiment and has a size of 320 mm × 420 mm in length and width. The diffusing plate 6 is separated from the light deflecting element 44 by 5 mm. Arranged.

  Further, in front of the diffusion plate 6, a diffusion film 7 for isotropically condensing or diffusing the light emitted from the diffusion plate 6 and the light emitted from the diffusion film 7 are substantially the light exit surface of the surface light source device. A prism sheet 8 for deflecting in the normal direction is provided.

  In the present embodiment, the total thickness of the surface light source device 40 (distance from the reflector 4 to the diffuser 6) is about 18 mm.

  According to the surface light source device 40 of the fourth embodiment, even when a CCFL light source is used as the primary light source, the same effect as that of the third embodiment can be obtained.

[Fifth Embodiment]
A surface light source device 50 according to a fifth embodiment of the present invention will be described with reference to FIGS. 12, 13, and 14.

  12 is a sectional view of the edge light type surface light source device 50, FIG. 13 is a sectional view taken along line XIV-XIV in FIG. 12, and FIG. 14 is taken along line XII-XII in FIG. FIG.

  As shown in FIGS. 12, 13, and 14, the surface light source device 50 includes a light guide plate 51 that is a plate formed of a transparent material. One end surface 51d of the light guide plate 51 is used as an incident end surface, and an end surface light source device 50 'that functions as a primary light source of the edge light type surface light source device 50 is disposed adjacent to the incident end surface 51d. This end surface light source device 50 'is also an embodiment of a direct type surface light source device of the present invention as described later.

  A prism sheet 8 that deflects light emitted from the light guide plate 51 in the normal direction of the output surface 51a is disposed on the output surface 51a of the light guide plate 51. A diffusion film 7 having functions of adjusting the viewing angle and preventing glare is disposed on the front side (upper side) of the prism sheet 8.

  In this embodiment, the light guide plate 51 is made of a transparent resin such as polymethyl methacrylate resin (PMMA), has a thickness of 3 mm at the incident end surface 51d, and a thickness at the end surface (opposite end surface) opposite to the incident end surface. Is a rectangular plate with a wedge-shaped cross-sectional shape of 1.5 mm (however, the thickness from the incident end face 51d to 5 mm remains 3 mm) and the vertical and horizontal dimensions are about 310 × 240 mm (corresponding to a 15-inch screen). is there.

  The light guide plate 51 has a light exit surface 51a processed into a mat surface having a fine uneven shape by mold transfer or the like, and a back surface 51b processed into a prism array forming surface.

  The mat surface of the exit surface 51a of the light guide plate 51 preferably has an average inclination angle θa in the range of 1 to 5 degrees from the viewpoint of improving the luminance uniformity on the exit surface. When the average inclination angle θa of the mat surface is smaller than 1 degree, the amount of light emitted from the light guide plate 51 tends to be small and sufficient luminance cannot be obtained. When the average inclination angle θa is larger than 5 degrees, a large amount of light is near the end face. This is because the emission light is significantly attenuated in the light guide direction within the exit surface, and the luminance uniformity on the exit surface tends to decrease.

  The exit surface 51a of the light guide plate 51 of the surface light source device 50 of the present embodiment has an average inclination angle θa in the vicinity of the incident end face 51d of about 1 degree and an average inclination angle θa in the vicinity of the opposite end face of about 3 °. The average inclination angle θa is adjusted so as to gradually increase from the incident end face 51d toward the opposite end face.

  The prism row forming surface of the back surface 51b of the light guide plate 51 controls the directivity of the light emitted from the light guide plate 51 on a surface parallel to the incident end surface 51d, and its apex angle is in the range of 90 to 110 degrees. It is preferable to do. This is because by setting the apex angle within this range, the emitted light from the light guide plate 51 can be appropriately condensed, and the luminance of the planar light source device 50 can be improved.

  In the surface light source device 50 of the present embodiment, the back surface 51b of the light guide plate 51 is a prism array forming surface in which a large number of prism arrays are formed, but a lens array such as a lenticular lens array or a V-shaped groove other than the prism array. May be formed so as to extend orthogonally to the incident end face 51d. Further, the prism row forming surface may be formed such that the top or valley of the prism row or the like is flat or curved.

  Further, in the present embodiment, the exit surface 51a of the light guide plate 51 is a mat surface and the back surface 51b is a prism array forming surface. Conversely, the exit surface 51a is a prism array forming surface and the back surface 51b is a mat. A surface configuration may be used.

  In addition, white dot printing may be performed on the back surface 51b of the light guide plate 51, or uneven dots such as a cylinder may be formed. It is preferable that the dot printing or the concavo-convex dots change the in-plane density so that the amount of light emitted from the emission surface 51a of the light guide plate 51 is uniform.

  In the surface light source device 50, the prism sheet 8 is formed by arranging a large number of elongated prism rows having an isosceles triangular cross section with apex angle of 60 to 75 ° having apexes on the light guide plate 51 side without any gaps. Light emitted obliquely from the optical plate 51 is totally reflected internally by the prism surface of the prism row, and deflected in the normal direction of the prism sheet 8 (normal direction of the output surface 51a of the light guide plate 51). .

  In the surface light source device 50 of the present embodiment, the prism sheet 8 provided with the prism row having apexes on the light guide plate 51 side is disposed on the emission surface 51a of the light guide plate 51, but has apexes on the opposite side. You may use the prism sheet provided with the prism row | line | column. When a prism sheet having a prism row having a vertex on the side opposite to the light guide plate exit surface 51a is used, the apex angle of the prism row is set to 85 to 100 °, and between the prism sheet and the light guide plate exit surface 51a. In addition, it is preferable to dispose a diffusion film that diffuses and deflects light emitted from the light guide plate 51. Thereby, the light can be deflected in the normal direction of the emission surface 51 a of the light guide plate 51.

  Further, the surface light source device 50 includes a diffuse reflection plate 4 disposed on the back surface 51 b side of the light guide plate 51. The diffuse reflection plate 4 is a rectangular thin sheet-like member disposed substantially parallel to the back surface 51b of the light guide plate 51, and is configured to diffuse and reflect light emitted from the back surface 51b of the light guide plate 51. Has been.

  Next, the end surface light source device 50 'will be described below.

  In the end surface light source device 50 ′ disposed adjacent to the incident end surface 51d of the light guide plate 51, the substrate 54 is disposed along the light guide plate incident end surface 51d, and the primary surface of the end surface light source device 50 ′ is disposed on the substrate 54. A total of 26 LED light sources 52 functioning as light sources are attached at a light source pitch distance of 12 mm. In the present embodiment, the LED light source 52 is an LED light source composed of RGB-multi LEDs in which RGB colors are arranged in one package. In the present embodiment, as the LED light source 52, for example, a product name 6-lead MULTITILED (LRTB G6SG) manufactured by OSRAM can be used. The LED light source 52 is driven with a current of about 20 mA. Here, the drive current is only a guideline, and in practice, the drive current is appropriately controlled by a sensor and a controller in order to achieve a good white color.

  The substrate 54 has a size of about 310 mm × 3.5 mm × 2 (t) mm, and is made of an aluminum material having excellent heat dissipation in order to efficiently dissipate heat generated by the LED light source 52.

  The partition wall 5 is arranged so that 26 compartments 2 ′ are formed corresponding to each LED light source 52, and the dimension of the compartment opening, that is, the dimension of the compartment 2 ′ is 12 mm × 3 mm, and the height is high. = 10 mm, pitch distance P = 12 mm, and perpendicular to the reflector 53. In this embodiment, the partition wall 5 is formed of a light diffusive reflection sheet (RF188 made by Tsujiden, thickness 188 μm, spectral reflectance of light having a wavelength of 600 nm, 95.5%).

  The reflection plate 53 formed on the substrate 54 is disposed so as to cover a region other than the opening of the LED light source 52. The reflection plate 53 recycles the light reflected by the light guide plate 51 and the partition wall and directs the light toward the light guide plate 51 again. In the present embodiment, as the reflection plate 53, the same material as the diffuse reflection sheet forming the partition wall 5 is used.

  Further, an isotropic diffusion film 55 having a light collecting function is disposed between the partition wall 5 and the incident end face 51d of the light guide plate 51 in parallel with the incident end face 51d. This diffusion film 55 functions as a diffusion plate of the surface light source device of the present invention. Furthermore, an optical deflection element similar to that of the third embodiment shown in FIGS. 7 and 8 may be disposed between the partition wall 5 and the diffusion film 55. The light deflection element is preferably arranged in parallel with the diffusion film 55.

  In such an end surface light source device 50 ′ of this embodiment, the light emitted radially from each LED 52 is subjected to multiple reflections including reflection by the partition surface in the compartment 2 ′. Is good. The light emitted from the end surface light source device enters the incident end surface 51d of the light guide plate 51, is introduced into the light guide plate 51, propagates through the light guide plate, and finally exits from the output surface 51a.

  Here, since the light emitted from the LED light source 52 is adjusted to be uniform light in the partition wall and then incident on the incident end surface 51d of the light guide plate 51, the light exiting surface 51a, particularly in the vicinity of the light guide plate incident end surface 51d. Occurrence of bright lines, dark lines, and eyeball defects (a phenomenon in which the portion corresponding to the LED becomes particularly bright) is suppressed, thus improving the surface light source quality and obtaining a surface light source device with good luminance uniformity.

  In the present embodiment, the LED light sources 52 as primary light sources are arranged in a row in the end surface light source device 50 ′. However, in the present invention, the primary light source array in the end surface light source device 50 ′ is set according to the width of the light guide plate incident end surface 51d. In other words, the compartment arrangement can be two or more.

  The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention.

  For example, the number and arrangement of the LED light sources and LED chips to be arranged are not limited to those described in the above embodiments, and can be arbitrarily set in consideration of the size of the surface light source device, the LED module, and the like. Similarly, the number and arrangement of LED modules can be arbitrarily set.

  In the above embodiment, the LED light source using a combination of a plurality of colors is configured to generate red, green, and blue light. However, the present invention is not limited to this, and a combination of light sources that generate different wavelengths. If so, the wavelength is arbitrary. In addition, the LED light source using a combination of a plurality of colors is not limited to one that generates light of three types of wavelengths, and may be a combination of those that generate at least two types of wavelengths of light.

  Hereinafter, embodiments of the present invention will be described in detail.

Example 1
The surface light source device belonging to the first embodiment was produced as follows.

  In this embodiment, the LED light source is a white light emitting diode (LED) and is of a Lambertian emission type having a light emission light distribution of ± 80 ° with respect to the normal direction of the emission surface (Philips Lumileds lighting Company) LUXEON-LXHL-PW01) was used.

  As a substrate on which the LED light source is arranged, an aluminum substrate having a size of about 40 mm × 40 mm × 2 (t) mm was used, and one LED light source was arranged at the center on the substrate.

  The board | substrate which has arrange | positioned the LED light source arranged 3x3 piece | piece (a total of nine arrangement | positioning) vertically and horizontally by the pitch distance L = 40mm of LED light source. Here, the size of the entire opening surface of the surface light source device was 120 mm long × 120 mm wide.

  Moreover, the heat-radiation fin made from aluminum was attached to the back surface of the board | substrate which has an LED light source through the silicon heat-transfer sheet | seat (Kitakawa Kogyo Co., Ltd. product, silicon heat conductive sheet product number; 430-6510).

  A reflector having a size of 120 × 120 mm (RF188 made by Tsujiden, thickness 188 μm, spectral reflectance of light having a wavelength of 600 nm, 95.5%) was disposed above the substrate. Here, the reflection plate was provided with a circular opening having a diameter of about 6.5 mm at a position corresponding to the LED light source.

  Subsequently, a partition wall was disposed immediately above the reflector. As the partition wall, a light diffusion reflection sheet (RF188 manufactured by Tsujiden, thickness 188 μm, spectral reflectance of light having a wavelength of 600 nm, 95.5%) was used. This was formed into a square frame having a square with an opening surface of 40 mm square and a height of H = 20 mm, and the square frame was bonded in three vertical rows and three horizontal rows. The partition was arranged so that the LED light source was located at the center of the compartment opening surface. Accordingly, the LED light sources were arranged in a total of nine compartments in three rows and three rows.

  Above the upper end of the partition wall, a 2 mm thick acrylic diffuser (manufactured by Mitsubishi Rayon, trade name Acrylite NA88, transmittance 63%, haze 90%) was disposed.

  The dimensions of the diffusion plate were about 125 × 125 mm in length and width, and a black tape was applied to the inside 5 mm from the end of the diffusion plate to form a frame. Therefore, the size of the entire opening surface of the surface light source device was a square of about 115 × 115 mm in length and width.

  Subsequently, a diffusion film having the same size as the diffusion plate (Kimoto product, Light-up DX100) and a prism sheet (Sumitomo 3M product, BEF-III) are sequentially stacked on the upper side of the diffusion plate. A light source device was formed.

  In this example, the total thickness of the surface light source device (distance from the reflecting plate to above the diffusing plate) was about 23 mm.

(Example 2)
A surface light source device was formed in the same manner as in Example 1 except that the height H of the partition walls shown in Table 1 and the distance D from the partition walls to the diffusion plate were changed.

(Example 3 to Example 4)
The point of changing the type of LED light source to the side-emitter emission type (LUXEON-LXHL-DW01 of Philips Lumileds lighting Company) listed in Table 1, and further changing the height H of the partition wall and the distance D from the partition wall to the diffusion plate A surface light source device was formed in the same manner as in Example 1 except for.

(Examples 5 to 8)
Without changing the aperture size of the surface light source device, the pitch distance of the LED light source was changed to 60 mm, and 2 × 2 (total of 4 arrays) were arranged in the vertical and horizontal directions, and the partition wall height H described in Table 1, And the surface light source device was formed like Example 3 except the point changed into the distance D from a partition to a diffusion plate.

Example 9
The surface is the same as in Example 1 except that the optical deflecting element is disposed between the partition wall and the diffusion plate, and further, the partition wall height H shown in Table 1 and the distance D from the partition wall to the diffusion plate are changed. A light source device was formed.

  Here, the light deflection element is a corner cube lens sheet in which triangular pyramids having an apex angle of 90 ° and L = 30 μm are arranged as described in the third embodiment, with the dimensions of about 125 × 125 mm and the lens surface facing upward. Arranged.

(Example 10 to Example 11)
The surface is the same as in Example 5 except that an optical deflecting element is disposed between the partition wall and the diffusion plate, and further, the partition wall height H shown in Table 1 and the distance D from the partition wall to the diffusion plate are changed. A light source device was formed.

  Here, the corner cube lens sheet of Example 9 was similarly arranged as the light deflection element.

(Example 12)
A surface light source device was formed in the same manner as in Example 4 except that an arc-shaped cutout recess having a depth of 10 mm, a radius of 25 mm, and a chord length of 40 mm was formed in the upper part of the partition wall.

(Example 13)
A surface light source device was formed in the same manner as in Example 12 except that an optical deflection element was disposed between the partition wall and the diffusion plate.

  Here, the corner cube lens sheet described in Example 9 was similarly arranged as the light deflection element.

(Comparative Examples 1-2)
A surface light source device was formed in the same manner as in Example 1 except that the partition wall was not formed and the distance D from the partition wall to the diffusion plate was changed to that shown in Table 2.

(Comparative Example 3 to Comparative Example 4)
The point that the partition wall is not formed, the aperture distance of the surface light source device is not changed, the pitch distance of the LED light source is changed to 60 mm, and 2 × 2 (total of 4 arrays) are arranged vertically and in Table 2. A surface light source device was formed in the same manner as in Comparative Example 1 except that the type of the LED light source and the distance D from the partition wall to the diffusion plate were changed.

[Evaluation]
The surface light source devices obtained in the above examples and comparative examples were evaluated as follows.

  The LED light source was energized with a current of 300 mA and allowed to stand for 20 minutes after the LED light source was turned on. The luminance distribution after 20 minutes was measured with a luminance meter: ProMetric-1400 (product of Radiant Imaging, USA). The distance between the luminance meter and the upper surface of the surface light source device was set to 600 mm.

  From the obtained in-plane luminance distribution data, the average luminance and standard deviation of the center line luminance of the surface light source device (in-plane luminance variation, that is, brightness / darkness unevenness) were calculated. The results are shown in Tables 1 and 2.

  The surface light source devices of Comparative Example 1 and Comparative Example 3 had a large standard deviation, a nonuniform luminance distribution, and poor luminance uniformity.

  The surface light source devices of Comparative Example 2 and Comparative Example 4 were excellent in luminance uniformity, but the total thickness of the surface light source devices was thick.

  The surface light source devices of Examples 1 to 4 had a smaller standard deviation than that of Comparative Example 1, and were excellent in luminance uniformity. In particular, the surface light source device of Example 1 had higher luminance than the surface light source device of Comparative Example 2, the total thickness of the surface light source device was thin, and the luminance uniformity was excellent.

  Regarding the surface light source devices of Examples 5 to 7, the standard deviation was smaller than that of the surface light source device of Comparative Example 3, and the luminance uniformity was excellent. Furthermore, although the luminance was lower than that of the surface light source device of Comparative Example 4, the total thickness of the surface light source device was thin and the luminance uniformity was excellent.

  As compared with the surface light source devices of Example 1 and Example 2, the brightness uniformity of the surface light source devices of Example 8 and Example 9 was further improved.

  In addition, the brightness uniformity of the surface light source devices of Example 10 and Example 11 was further improved as compared with the surface light source devices of Example 6 and Example 7 as described above.

  The surface light source device of Example 12 was superior in luminance and luminance uniformity as compared with the surface light source device of Example 4.

  As compared with the surface light source device of Example 4, the surface light source device of Example 13 was further improved in brightness uniformity.

It is sectional drawing of the surface light source device of 1st Embodiment of this invention. It is sectional drawing along the II-II line of FIG. It is sectional drawing of the surface light source device of 2nd Embodiment of this invention. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is the figure which looked at the model which has arrange | positioned the primary light source in each of four compartments divided by the partition from the upper direction. It is sectional drawing along the VI-VI line of FIG. It is sectional drawing of the surface light source device of 3rd Embodiment of this invention. It is sectional drawing along the VIII-VIII line of FIG. It is an enlarged plan view of the light deflection element in the third embodiment of the present invention. It is sectional drawing of the surface light source device of 4th Embodiment of this invention. It is sectional drawing along the XX line of FIG. It is sectional drawing of the surface light source device of 5th Embodiment of this invention. It is sectional drawing along the XIV-XIV line | wire of FIG. It is sectional drawing along the XII-XII line | wire of FIG.

Explanation of symbols

1, 20, 30, 40, 50 Surface light source device 2, 21, 32, 42, 52 Primary light source 2 'Compartment 3, 54 Substrate 4, 53 Reflector 5 Partition 5a Notch 6, 55 Diffuser 7 Diffuser 8 Prism sheets 31, 44 Light deflection element 50 'End surface light source device 51 Light guide plate 51a Outgoing surface 51b Back surface 51d Incident end surface

Claims (11)

A plurality of primary light sources arranged in at least one direction;
A reflector positioned below the light emitting portion of the plurality of primary light sources;
A partition wall formed on the reflector and formed to form a compartment corresponding to each of the plurality of primary light sources, and made of a member that reflects at least part of the incoming light;
A diffusion plate disposed above the partition and the compartment;
A surface light source device comprising: The arrangement pitch distance L (mm) of the plurality of primary light sources, the height H (mm) of the partition walls, and the distance D (mm) between the partition walls and the diffusion plate are expressed by the following equations (1) and (2).
H ≧ 0.25L + 10−D (1)
0 ≦ D ≦ 0.25L (2)
The surface light source device according to claim 1, wherein:   The surface light source device according to claim 1, wherein at least one light deflection element is disposed between the partition wall and the diffusion plate.   4. The notch according to claim 1, wherein the partition wall is formed with a notch in an upper portion between at least one pair of the compartments adjacent to each other. 5. Surface light source device.   5. The surface light source device according to claim 1, wherein a shape of a compartment opening formed above the compartment is a square, a rectangle, or a hexagon.   6. The surface light source device according to claim 1, wherein the plurality of primary light sources are arranged in at least two directions, and the partition walls are formed in a lattice shape. .   The surface light source device according to claim 1, wherein each of the plurality of primary light sources includes at least one light emitting diode.   The surface light source device according to any one of claims 1 to 6, wherein each of the plurality of primary light sources includes at least one cold cathode tube.   The surface according to any one of claims 1 to 8, wherein a diffusion film is disposed above the diffusion plate, and a light deflection element is disposed above the diffusion film. Light source device. A light guide plate having an entrance end face and an exit face, guiding light introduced through the entrance end face and emitting the light from the exit face;
An end surface light source device comprising the surface light source device according to any one of claims 1 to 7, which is disposed adjacent to an incident end surface of the light guide plate;
Including
A surface light source device, wherein light emitted from the end surface light source device is incident on an incident end surface of the light guide.   11. The surface light source device according to claim 10, wherein a diffusion film is disposed above an emission surface of the light guide plate, and a light deflection element is disposed above the diffusion film.

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