WO2014016913A1 - 照明装置及びこれを用いた映像表示装置 - Google Patents
照明装置及びこれを用いた映像表示装置 Download PDFInfo
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- WO2014016913A1 WO2014016913A1 PCT/JP2012/068752 JP2012068752W WO2014016913A1 WO 2014016913 A1 WO2014016913 A1 WO 2014016913A1 JP 2012068752 W JP2012068752 W JP 2012068752W WO 2014016913 A1 WO2014016913 A1 WO 2014016913A1
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- light shielding
- optical element
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133611—Direct backlight including means for improving the brightness uniformity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
- F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
- F21K9/68—Details of reflectors forming part of the light source
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V3/00—Globes; Bowls; Cover glasses
- F21V3/04—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings
- F21V3/10—Globes; Bowls; Cover glasses characterised by materials, surface treatments or coatings characterised by coatings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
- F21V9/30—Elements containing photoluminescent material distinct from or spaced from the light source
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21V5/00—Refractors for light sources
- F21V5/02—Refractors for light sources of prismatic shape
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2101/00—Point-like light sources
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2105/00—Planar light sources
- F21Y2105/10—Planar light sources comprising a two-dimensional array of point-like light-generating elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- F21Y2115/00—Light-generating elements of semiconductor light sources
- F21Y2115/10—Light-emitting diodes [LED]
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133603—Direct backlight with LEDs
Definitions
- the present invention relates to an illumination device and a video display device using the same as a backlight device, and more particularly to an illumination device using an LED (Light Emitting Diode) as a light source and a video display device using the same.
- LED Light Emitting Diode
- an optical element composed of two layers of a light source side transparent layer and a liquid crystal panel side diffusion layer is disposed between a light source (fluorescent tube, light emitting diode) and a liquid crystal panel, and the surface of the transparent layer or It is described that by providing a plurality of light shielding layers inside, the luminance and luminance uniformity of the light irradiated to the liquid crystal panel are improved.
- a light emitting diode (Light Emitting Diode, LED) generally used as a light source of a backlight device excites a phosphor and emits light of a desired wavelength.
- Patent Document 1 When the LED having such a configuration is used in Patent Document 1, the light emitted from the LED is reflected by the surface of the light shielding layer and reenters the phosphor of the LED. The phosphor of the LED is excited again by this incident light. The light generated by re-excitation of the phosphor changes the wavelength characteristics of light in the vicinity of the LED, particularly in the portion immediately above the LED (opposite the optical element), and the chromaticity immediately above the LED changes. For this reason, when it takes the structure which arrange
- the present invention includes an LED as a light source and an optical element for guiding or diffusing light from the LED, and a light shielding pattern is provided at a position corresponding to the LED of the optical element.
- the pattern is composed of at least two light shielding layers, and among the light shielding layers, the light shielding layer on the optical element side is composed of white ink, and at least one of the other light shielding layers is, for example, white and blue It is composed of mixed ink or white, blue and black mixed ink.
- a prism may be provided on the LED side of the optical element for further improvement in luminance unevenness.
- FIG. 6 is a diagram illustrating an example of the configuration of the ink 6 according to the first embodiment.
- the figure explaining the optical influence by the reflected light in the ink 6 Diagram showing general wavelength-transmittance characteristics of white ink Diagram showing the wavelength-transmittance characteristics of blue mixed ink that mixes white and blue
- FIG. 5 is a diagram illustrating a method for forming ink 6 according to Example 3 of the invention.
- the exploded perspective view which shows an example of the illuminating device which concerns on Example 5 of this invention.
- the figure which shows an example of the luminance distribution of an illuminating device FIG. 10 is a diagram illustrating an example of a prism 116 provided in an optical element 114 according to Example 6 of the invention.
- FIG. 10 is a diagram illustrating an example of a prism 117 provided in an optical element 114 according to Example 6 of the invention.
- the figure for demonstrating the effect by the prisms 116 and 117 The figure explaining the optical action in the extending direction of a prism
- stretching direction of a prism The figure which shows an example of the direction of luminance unevenness, and the extension direction of a prism
- the figure which shows the example which gave the rough surface process to the end surface of the light-shielding part diffuser plate 114 The figure which shows the example which provided the taper surface in the edge part of the light-shielding part diffusion plate 114
- the figure which shows an example of the light irradiation surface of LED The figure which shows an example of the illuminating device which concerns on Example 8 of this invention.
- FIG. 1 shows an exploded perspective view of a video display device and a lighting device according to Embodiment 1 of the present invention.
- the video display device of FIG. 1 includes a liquid crystal panel 1 as a display panel and an illumination device 100, and the illumination device includes a light source unit 11, a light shielding unit 12, and an optical sheet unit 13.
- the illumination device 100 operates as a backlight for irradiating the liquid crystal panel 1 with light from the back surface of the liquid crystal panel 1.
- the liquid crystal panel 1 controls the light transmittance of each liquid crystal pixel by an input video signal, and displays the image by spatially modulating the light from the illumination device with each liquid crystal pixel whose light transmittance is controlled.
- the lighting device 100 uses a light emitting diode (LED) that emits white light as a light source.
- the white diode has, for example, a yellow phosphor and an LED chip that emits blue light.
- the yellow phosphor is excited by a part of the blue light from the LED chip to emit light, and yellow light from the yellow phosphor is emitted.
- blue light from the LED chip are mixed to emit white light.
- the LED applied to the present embodiment is not limited to this configuration, and may have any configuration as long as it emits light of a desired color using a phosphor.
- each direction in FIG. 1 is defined as follows.
- the light emitting direction of the illuminating device 100 is the emitting surface side of the illuminating device 100, and the opposite direction is the back side of the illuminating device 100.
- the exit surface of the illumination device 100 is defined as the surface (exit surface) of various sheets constituting the optical sheet unit 13.
- the upper direction of the liquid crystal panel 10 or the illumination device 100 from which the light of the LED 2 is emitted is the + z direction
- the opposite direction that is, the lower direction of the liquid crystal panel 10 or the illumination device 100
- the rear side light source
- the direction from the part side to the exit surface side (optical sheet part side) and perpendicular to the z direction is the + y direction
- the opposite direction that is, the direction from the exit surface side to the back side
- the y direction is equal to the direction orthogonal to the exit surface of the illumination device 100, and the + y direction may be referred to as the exit surface side direction, and the ⁇ y direction may be referred to as the back side direction.
- the direction orthogonal to the yx plane and viewed from the exit surface side of the illumination device 100 is the + x direction, and the opposite direction is the ⁇ x direction.
- this embodiment will be described using this coordinate system unless otherwise specified.
- the exit surface side it shall point out the exit surface side of the illuminating device 100.
- the light source unit 11 includes an LED 2 as a light source, an LED substrate 3 as a light source substrate on which a plurality of LEDs 2 are mounted, a reflection sheet 4, and a base chassis 7.
- the LED 2 uses a side-view type white LED whose light emission direction is parallel to the electrode surface, and is mounted on the LED substrate 3 so as to emit white light in the + z direction. That is, the light emission direction of the LED is a direction parallel to the light emission surface of the illumination device, and an upward direction of the liquid crystal panel 10 or the illumination device 100 (short direction or vertical direction, above the paper surface in FIG. 1). is there.
- the LED board 3 has circuit elements and wirings for supplying power to the LED 2 and is, for example, a printed board made of glass epoxy resin.
- the LED substrate 3 has a horizontally long rectangular shape that extends in the x direction. That is, the longitudinal direction of the LED substrate 3 is equal to the horizontal direction of the liquid crystal panel 10 or the lighting device 100 (longitudinal direction or lateral direction, right and left direction in FIG. 1).
- a plurality of LEDs 2 are arranged in a line along the longitudinal direction of the LED substrate 3. If a plurality of LEDs arranged in a single row are LED rows, it can be said that the LED substrate 3 is provided corresponding to each LED row.
- the current supplied to the LED 2 is controlled by various circuits on which the LED substrate 3 is mounted.
- the base chassis 7 is made of a metal having high thermal conductivity, such as aluminum or iron, and has a bowl shape or a box shape facing the opening toward the liquid crystal panel 10 side. Then, a plurality of LED substrates 3 in which a plurality of LEDs 2 are arranged on the inner surface (outgoing surface side) are arranged and fixed at predetermined intervals along the z direction. Thereby, a plurality of LED rows are arranged along the light emitting direction (z direction) of the LEDs 2.
- the reflection sheet 4 is for directing the light toward the back side toward the exit surface side, and is made of, for example, a white and flat resin sheet.
- the reflection sheet 4 is attached to the inner surface (outgoing surface side) of the base chassis 7 so as to be located on the back side of the LED 2.
- the base chassis 7 is attached so that the reflection sheet 4 is sandwiched between the base chassis 7 and the LED substrate 3.
- the surface of the LED substrate 3 (surface on the exit surface side) is subjected to a reflective coating such as white paint in order to increase the reflection efficiency.
- the base chassis 7 is attached to the LED substrate 3, and the reflective sheet 4 provided with holes corresponding to the LEDs 2 is covered thereon, and the reflective sheet 4 is attached to the base chassis 7 with the LEDs 2 exposed from the holes of the reflective sheet 4. It may be attached.
- the surface of the LED substrate 3 is covered with the reflection sheet 4, and the reflective coating on the surface of the LED substrate 3 is not necessary.
- the reflection sheet 4 may be individually provided on the inner surface (outgoing surface side) of the base chassis 7 and the surface of the ED substrate 3.
- the light shielding unit 12 includes the optical element 1 and ink 6 as a light shielding pattern.
- the optical element 1 is a diffusion plate (transparent resin such as acrylic, polycarbonate, polystyrene, etc.) in which diffusible particles or beads are mixed, or the exit surface and / or back surface of the transparent resin is roughened.
- this diffusion plate is referred to as a “light-shielding portion diffusion plate”.
- the ink 6 as the light shielding pattern has an optical action so as to reflect or absorb the light from the LED 2 in the + y direction and reduce the luminance of the light in the + y direction.
- the optical sheet portion 13 is composed of one or a plurality of optical sheets 5.
- the optical sheet 5 is one of a diffusion plate, a diffusion sheet, a ⁇ lens sheet, a prism sheet having a light condensing effect, a brightness enhancement sheet that transmits predetermined polarized light and reflects other polarized components, or the like. It is comprised by these arbitrary combinations.
- the optical sheet 5 diffuses the light from the light-shielding portion 12 and / or increases the light component toward the exit surface, thereby improving spatial brightness uniformity and brightness on the exit surface.
- the LED 2 is a side-view type LED that emits light in the + z direction, but light leaks from the LED 2 package upward (in the + y direction), and further from the LED 2 by the reflection sheet 4 closest to the light emission side of the LED 2. Therefore, when viewed from the light emitting surface side of the illumination device 100, a so-called light spot (hot spot) in which the vicinity of the position of the LED 2 is locally brighter than other portions is generated. This hot spot is visually recognized as uneven brightness by the user. In order to prevent this, the brightness of the hot spot is reduced by reducing the amount of light in the vicinity of the position of the LED 2 on the light emitting surface of the optical element 1 with the ink 6 that is a light shielding pattern.
- the ink 6 is provided at a position corresponding to the arrangement position of the optical element (light-shielding part diffusion plate) 1 and LED 2 and its periphery (particularly the light emission side of LED 2).
- the ink 6 is provided on the light exit surface side (that is, the optical sheet portion 13 side) of the optical element 1.
- it may be provided on the back side of the optical element 1 (that is, on the light source unit 11 side) or on both.
- FIG. 2 is an enlarged perspective view of a portion including the LED 2 and the LED substrate 3 of the light source unit 11 and the optical agent 1 and the light shielding pattern ink 6 of the light shielding unit 12 when viewed from the ⁇ z direction side.
- FIG. 3 is a front view of a part including the light shielding part diffusion plate 1 of the light shielding part 12 and the ink 6 that is the light shielding pattern, as viewed from the + y direction (exiting surface side).
- FIG. 3 is a front view of a part including the light shielding part diffusion plate 1 of the light shielding part 12 and the ink 6 that is the light shielding pattern, as viewed from the + y direction (exiting surface side).
- the ink 6 as the light-shielding pattern in the present embodiment corresponds to the position of the LED 2 and has a size that covers the entire LED 2 from the emission surface side, and has an elliptical or oval shape with the x direction as the longitudinal direction.
- the first pattern 61 and the second pattern 62 around the first pattern 61 and arranged on the light emission direction side of the LED 2 are included.
- Such a light shielding pattern is formed, for example, as shown in FIG.
- a plurality of small squares shown in the lower left region indicate virtual unit blocks.
- the density of the dot-like ink 6 in the unit block is changed according to the position of the unit block as shown in the enlarged view of the four unit blocks on the left side of FIG.
- the ratio (density) occupied by the ink 6 is 100% (that is, the unit block is filled with the ink 6).
- the proportion (density) of the ink 6 in the unit block in which the second pattern 62 is formed varies in the range of, for example, 80 to 10% according to the distance from the first pattern 61. For example, as the distance from the first pattern 61 increases or decreases, the density of the ink 6 in the unit block in which the second pattern 62 is formed is gradually decreased.
- the light transmittance of the portion corresponding to the LED 2 can be made the lowest, and a light-shielding pattern having such characteristics that the light transmittance gradually increases as the distance from the LED 2 in the light emission direction of the LED 2 can be obtained. Since the light intensity of the hot spot described above has a characteristic of gradually decreasing as the distance from the LED 2 increases, if the light transmittance characteristic of the light shielding pattern is configured as described above so as to match the characteristic of the hot spot, the hot spot can be satisfactorily obtained. The brightness can be reduced.
- the unit block is virtual and does not appear on the optical element 1.
- the size of the unit block and the size of the dots of the ink 6 can be appropriately changed depending on the optical structure of the light source unit 11, the light emission characteristics of the LED 2, the distance from the optical element 1 to the optical sheet unit 5, and the combination of the optical sheets.
- the present embodiment is characterized in that the lighting device having such a structure has a multilayer structure in which a plurality of light-shielding layers (ink layers) are laminated on the ink 6 as a light-shielding pattern.
- the lighting device having such a structure has a multilayer structure in which a plurality of light-shielding layers (ink layers) are laminated on the ink 6 as a light-shielding pattern.
- FIG. 4 is a cross-sectional view parallel to the yz plane showing the laminated structure of the ink 6 as the light shielding pattern according to the first embodiment, particularly the first pattern.
- the LED board 3 is arrange
- the configuration of the reflection sheet 4 is not limited to this.
- the optical element 1 (light-shielding part diffuser plate) is arranged in the + y direction so as to be separated from the reflective surface of the reflective sheet 4 or the surface of the LED substrate 3 by a predetermined distance. Therefore, a space having a predetermined interval is formed between the reflection sheet 4 and the optical element 1.
- the LED 2 is arranged in this space, and the LED 2 emits light in the + z direction in this space. That is.
- the optical axis of the LED 2 is parallel to the surface of the reflection sheet 4 or the optical element 1 and the z direction.
- the light emitted from the LED 2 in the + z direction with a predetermined emission angle is repeatedly reflected between the reflection sheet 4 and the optical element 1, and a part of the light passes through the optical element 1 while + z in the space. Propagate in the direction.
- FIG. 4 only the light which goes directly to the optical element 1 among the light from LED is shown as an arrow.
- the ink 6 has a three-layer structure and is defined as a first layer, a second layer, and a third layer in order from the optical element 1 side or the LED 2 side to the optical sheet 5 side.
- the color of each layer of the ink 6 is white for the first layer, white for the second layer, and a mixture of white and blue for the third layer. That is, the layer (first layer) located closest to the optical element has a higher white ratio (white purity) than at least one of the other layers.
- the white ratio of the first layer is 100%, that is, it is composed of only white ink and other colors are not mixed. However, it is not necessarily required to be 100%. For example, other colors such as blue and black may be mixed at a ratio smaller than a blend ratio of a blue ink or a black ink in a mixed ink described later.
- other colors such as blue and black may be mixed at a ratio smaller than a blend ratio of a blue ink or a black ink in a mixed ink described later.
- the optical action of the first layer of white ink will be described.
- the transmittance of the optical element 1 is 80%
- the transmittance and absorption rate of each ink layer are 30% and 10%, respectively
- the dimension of the ink 6 extending in the + z direction from the light emitting side of the LED 2 is 10 mm
- the light emission of the LED 2 The distance in the + y direction between the center of the surface and the optical element 1 is 3.4 mm.
- the second layer ink is also composed of white ink in order to suppress absorption of the transmitted light from the first layer (8.1% of the total light amount).
- the first layer ink and the second layer ink have a function of improving the light utilization efficiency.
- FIG. 5 shows the optical influence of the reflected light from the ink 6.
- part of the light reflected from the ink 6 is incident on the LED 2, and the phosphor of the LED 2 is re-excited by this incident light.
- the chromaticity of light (hot spot) immediately above the LED changes depending on the color of the phosphor of the LED 2.
- the chromaticity of the light (hot spot) immediately above the LED changes from yellow to red.
- the chromaticity of the light transmitted through the first and second layers of the ink 6 also changes due to the optical characteristics of the ink 6.
- a general white ink has a wavelength-transmittance characteristic (transmission spectrum) that increases the transmittance on the long wavelength side, as shown in FIG. For this reason, the light in the vicinity of the LED 2 having a particularly strong light amount changes in chromaticity in the yellow to red direction as compared with the surrounding area.
- the light directly above the LED 2 has a large chromaticity and a long wavelength due to the chromaticity change in the yellow to red direction due to re-excitation of the phosphor of the LED 2 and the chromaticity change of the transmitted light due to the optical characteristics of the white ink. Will shift or change sideways.
- a change in chromaticity occurs, local color unevenness occurs immediately above the LED 2, and spatial color uniformity deteriorates in the exit surface of the illumination device 100. That is, the hot spot generated in the immediate vicinity of the LED 2 not only has a locally higher brightness than the surrounding area, but also has a locally different color compared to the surrounding area, and particularly has a strong yellow or red component.
- the blue mixed ink has a wavelength-transmittance characteristic (transmission spectrum) that does not absorb light in the blue wavelength region on the short wavelength side but absorbs much light on the long wavelength side. ing. Therefore, if the blue mixed ink is used for the third layer of the ink 6, the light transmitted through the first layer and the second layer immediately above the LED 2 having a strong yellow or red component is transmitted by the third layer to the yellow or Red component is absorbed. That is, the yellow or strong red light transmitted through the first layer and the second layer can be corrected by the third layer and returned to white.
- the blue mixed ink has a wavelength-transmittance characteristic (transmission spectrum) that does not absorb light in the blue wavelength region on the short wavelength side but absorbs much light on the long wavelength side. ing. Therefore, if the blue mixed ink is used for the third layer of the ink 6, the light transmitted through the first layer and the second layer immediately above the LED 2 having a strong yellow or red component is transmitted by the third layer to the yellow or Red component is absorbed. That is, the
- the chromaticity adjustment amount in the third layer can be set by changing the blending amount of the blue ink of the blue mixed ink with the chromaticity of the irradiation light of the illumination device as the target chromaticity, for example.
- the mixing ratio of the blue ink to the white ink is, for example, about 0.1 to 0.4% by weight.
- the blue mixed ink in the third layer has a function of adjusting or correcting the chromaticity of light in the vicinity immediately above the LED 2.
- the ink 6 as the light shielding pattern formed on the optical element has a multilayer structure in which a plurality of light shielding layers are stacked, and the light shielding layer (the book 2) located on the backmost side (LED 2 side).
- the first layer is made of white ink
- at least one of the other light shielding layers is made of blue mixed ink. While reducing the intensity, the change in chromaticity due to the phosphor of the LED 2 and the white ink in the first layer can be reduced. Therefore, according to the present embodiment, it is possible to provide an illumination device with improved spatial brightness uniformity and color uniformity of the irradiation light. Further, when the illumination device according to this embodiment is used as a backlight of a liquid crystal display device, a high-quality image with high spatial luminance uniformity and color uniformity can be displayed.
- the light shielding pattern has a three-layer structure in order to ensure the thickness of the light shielding pattern, but the present invention is not limited to this. If the thickness of each layer can be increased, two layers may be realized. Needless to say, a four-layer structure may also be used.
- the first pattern 61 it is obvious that the second pattern 62 may have a multilayer structure as well.
- the first pattern 61 may have a multilayer structure, and the second pattern 62 may have a single layer structure.
- Example 2 of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the composition of the third layer ink, the description other than the third layer ink is omitted.
- the ink 6 according to the present embodiment is composed of ink in which white, blue and black are mixed in the third layer (hereinafter referred to as “blue-black mixed ink”).
- blue-black mixed ink the hot spots can be favorably reduced with a small number of printing steps.
- the light shielding pattern In order to suppress the hot spot directly above the LED 2, the light shielding pattern needs to have a film thickness of about 16 ⁇ m. However, in order to reproduce a fine pattern by printing, it is necessary to reduce the number of meshes of the printing plate. . However, making the mesh of the printing plate fine means that the film thickness is reduced by one printing. In fact, if a dot having a size of 0.47 ⁇ m is to be created, it is necessary to use a printing plate having a mesh number of 350 ⁇ 350. Since the film thickness at the time of one-time printing by such a printing plate is about 4 ⁇ m to 5 ⁇ m, 3 to 4 times of printing are required to obtain a film thickness of 16 ⁇ m. An increase in the number of times of printing leads to an increase in printing cost. Therefore, in order to achieve both a fine pattern and a reduction in the number of printings, a new device for suppressing hot spots is required.
- the light absorption rate in the third layer is increased by using a blue-black mixed ink as the third layer ink.
- a blue-black mixed ink as the third layer ink.
- the mixing ratio of the blue ink and the black ink to the white ink is, for example, about 0.1 to 0.4% by weight.
- the blue-black mixed ink When the blue-black mixed ink is used for the first layer, the amount of light absorbed by the first layer increases, and the amount of light reflected by the first layer and propagated in the z direction decreases, so the light utilization efficiency decreases.
- the blue / black mixed ink is used for the third layer, a decrease in the amount of light propagating in the z direction can be suppressed. That is, according to the present embodiment, it is possible to reduce the light intensity of the hot spot while suppressing the chromaticity change of the light immediately above the LED 2 with a light-shielding pattern with a thin film thickness (that is, a small number of printings). it can.
- the light shielding pattern may have a two-layer structure or a four-layer structure.
- Example 3 of the present invention will be described with reference to FIG.
- the third embodiment is different from the first and second embodiments in the ink layer structure and the ink forming method, and the other parts are the same. Therefore, the description of the parts other than the ink forming method is omitted.
- the light shielding pattern 6 has a two-layer structure, the first layer is composed of white ink, and the second layer is composed of blue-black mixed ink.
- the first layer composed of white ink is printed using a gradation printing plate, and the second layer composed of mixed color ink (blue mixed ink or blue black mixed ink) is printed using a solid printing plate. is doing.
- the gradation printing plate prints white ink on the optical element 1 so that the area of the pattern decreases as the distance from the LED 2 increases, that is, the dot density per unit block shown in FIG. 3 decreases. As described above, the white ink absorbs little, so that it can be applied over a wide range to achieve optimum light shielding performance and to achieve desired luminance uniformity.
- the solid printing plate prints the blue mixed ink or the blue-black mixed ink only on the hot spot portion directly above the LED 2, for example, only on the first pattern 61 in FIG.
- the first pattern 61 and the second pattern 62 in FIG. 2 are printed with white ink so as to cover a wide range with the gradation printing plate, and the first layer is formed by the solid printing plate.
- the second layer is formed by printing only the portion directly above, that is, the portion of the first pattern 61 with the mixed color ink. That is, in this embodiment, the first layer formed with the white ink by the gradation printing plate has both the first pattern 61 and the second pattern 62, and the blue printing ink or the blue-black mixing ink by the solid printing plate.
- the formed second layer has only the first pattern 61. That is, the first pattern 61 has a multilayer structure, and the second pattern 62 has a single layer structure.
- the mixed-color ink is the blue mixed ink or the blue-black mixed ink described above, but any other mixed-color ink may be used as long as it has a higher light absorption rate than the first layer ink and can correct the chromaticity change. But you can.
- the mixing ratio of the blue ink and the black ink to the white ink is, for example, about 0.1 to 0.4% by weight.
- the printing process is performed twice, but printing may be performed as many times as necessary to obtain a required film thickness.
- Example 4 of the present invention will be described with reference to FIG. Since the ink layer structure of the fourth embodiment is different from that of the foregoing embodiment and the other parts are the same, the description of the parts other than the ink layer structure is omitted.
- the first layer of ink 6 is composed of white ink
- the second layer is blue-black mixed ink
- the third layer is composed of white ink.
- the light reflected and returned from the optical sheet portion 5 side to the surface of the third layer ink can be reflected without being absorbed by the third layer.
- the brightness of the irradiation light of the illumination device 100 can be improved.
- the blue / black mixed ink is used for the second layer, similarly to the second embodiment, the light transmitted through the first layer can be absorbed well and the light intensity of the hot spot can be reduced.
- the mixing ratio of the blue ink and the black ink to the white ink is, for example, about 0.1 to 0.4% by weight.
- the light shielding pattern (ink 6) needs to have at least a three-layer structure, and the number of times of printing increases, but the light utilization efficiency increases.
- the second layer is a blue-black mixed ink, but may be a blue mixed ink as long as the hot spots can be suppressed with the total film thickness of the first to third layers.
- Example 5 of the present invention will be described with reference to FIG.
- the present embodiment is different from the first to fourth embodiments in the configuration of the optical element (light-shielding part diffusion plate).
- FIG. 11 is a developed perspective view showing the configuration of the illumination device according to the fifth embodiment, and the optical sheet portion 13 is not shown.
- the LED substrate 314 is divided into two in the x direction, and the rectangular light-shielding portion whose longitudinal direction is the x direction corresponding to each of the divided LED substrates 314.
- a diffusion plate 114 is provided.
- an example in which ten LED substrates 314 and ten light-shielding part diffusion plates 114 are used is shown.
- the optical element is configured with a single light-shielding part diffusion plate 1 having a size (area) that covers the exit surface of the illumination device 100, whereas in this embodiment, a plurality of optical elements are formed.
- Each of the light-shielding part diffusion plates 114 is smaller than the light-shielding part diffusion plate 1 and corresponds to the LED substrate 314.
- Each light-shielding part diffusion plate 114 has a size of about 1/10 that of the optical element 1 in this embodiment.
- the light shielding part diffusion plate 114 By configuring the light shielding part diffusion plate 114 as in the present embodiment, it is possible to suppress the bending of the light shielding part diffusion plate 114 due to heat. Hereinafter, such an effect will be described.
- the resin-made optical element disposed in the vicinity of the light source undergoes thermal expansion due to heat generated by the light source or a circuit (driver) that supplies power to the light source, and thus, for example, on the liquid crystal panel side. Deflection that warps toward the convexity occurs. Due to this bending, the distance between the light source and the optical element changes according to the position on the surface of the optical element, and this appears as uneven spatial luminance in the surface.
- the expansion amount (elongation amount) ⁇ L of the object is generally expressed by the following formula 1.
- ⁇ L ⁇ ⁇ L ⁇ ⁇ T (Formula 1)
- ⁇ L the expansion amount
- ⁇ the linear expansion coefficient
- L the length of the object
- ⁇ T the temperature rise value
- ⁇ a physical property value unique to the object. That is, the amount of expansion ⁇ L increases as the length L of the object increases, and increases as the temperature rise ⁇ T around the object increases.
- the thermal expansion amount that is, the bending becomes small. A change in the distance between the LED 2 and the light shielding part diffusion plate 114 due to heat can be reduced.
- the bend can be further suppressed by fastening the light shielding part diffusion plate 114 and the base chassis 7 together with a rivet pin or the like.
- the rivet pin may be constituted by a screw or the like. These rivet pins and screws are made of transparent or white and highly reflective materials, making the rivet pins and screws difficult to see as dark areas, and the effect of these components on the optical performance of the lighting device is minimized. Can be suppressed.
- one light-shielding part diffusion plate 114 is arranged corresponding to one LED substrate 314. That is, since the number of LED substrates 314 and the number of light-shielding part diffusion plates 114 are the same, assembly in units of substrates is facilitated during assembly, and the degree of assembly is increased.
- the present embodiment is not limited to this.
- the LED substrate 314 may be divided into only one for each LED row without being divided, and two or more optical elements 114 may be arranged corresponding to the one LED substrate 314. As the number of divisions of the light-shielding part diffusion plate increases, the amount of thermal expansion decreases, which is effective for improving luminance unevenness.
- the number of divisions of the light shielding part diffusion plate can be appropriately determined in consideration of the assembly man-hours and cost.
- a method of sequentially attaching the reflection sheet 4, the LED board 314, and the light shielding part diffusion plate 114 to the base chassis 7 may be used.
- the LED board 314 and the light shielding part diffusion plate 114 may be assembled first. After the conversion, a method of attaching to the base chassis 7 so that the reflection sheet 4 is sandwiched between the module and the base chassis 7 may be used.
- the optical element As described above, according to the present embodiment, it is possible to prevent the optical element from being bent due to thermal expansion, and to reduce luminance unevenness due to the bending.
- Embodiment 6 of the present invention will be described with reference to FIGS.
- the present embodiment is different from the other embodiments in that a prism for forming a light propagation groove is provided on the back side of the optical element 114 in order to reduce luminance unevenness.
- a prism for forming a light propagation groove is provided on the back side of the optical element 114 in order to reduce luminance unevenness.
- the diagram on the right side of FIG. 12 shows the luminance distribution on the one-point difference line on the left side.
- the light shielding part diffuser plate 114 of Example 5 is used as the optical element, and the light shielding pattern (ink 6) of Examples 1 to 4 is not provided.
- the dimension (width) in the z direction of the light shielding part diffusion plate 114 is A [mm]. The width A is smaller than the arrangement pitch of the LEDs 2 in the z direction.
- the luminance distribution of this example has a peak of luminance L1 immediately above the arrangement position of LED1 and LED2.
- the minimum luminance L2 is in the vicinity of the side opposite to the light emission direction of the LED ( ⁇ z side).
- the difference between the peak luminance L1 and the minimum luminance L2 is large, and this is visually recognized as luminance unevenness.
- the light shielding part diffusion plate has diffusibility as described above, it is difficult to reduce the luminance unevenness only by the diffusibility of the light shielding part diffusion plate.
- a light shielding pattern (ink 6) as shown in the above-described Examples 1 to 4 is formed at a position corresponding to the LED directly above the light shielding portion diffusion plate 114, and light directed to the position is emitted. What is necessary is just to absorb and reflect with a light-shielding pattern.
- the prisms 116 and 117 for forming the light propagation grooves 120 on the back side of the light shielding portion diffusion plate 114 that is an optical element a light shielding pattern is provided.
- the light reflected by is efficiently guided in the + z direction.
- the prism 116 in FIG. 13 has a triangular cross section (cross section parallel to the xy plane) orthogonal to the light emission direction (optical axis) of the LED 2 and extends in the z direction, that is, a direction parallel to the light emission direction of the LED 2. Is formed.
- a plurality of the prisms 116 are arranged in the x direction.
- FIG. 14 has a triangular cross section (cross section parallel to the yz plane) that is parallel to the light emission direction (optical axis) of the LED 2 and orthogonal to the surface of the light-shielding portion diffusing plate 114, and in the x direction. That is, it is formed to extend in a direction orthogonal to the light emitting direction of the LED 2.
- a plurality of prisms 117 are arranged in the x direction. That is, in the example of FIG. 13 and the example of FIG. 14, the prism formation directions are orthogonal to each other.
- illustration of the ink 6 that is a light shielding pattern for simplification of illustration is omitted.
- FIG. 15 shows a graph of the minimum luminance increase rate with respect to the width A of the light-shielding part diffusing plate 114 in the respective configurations of FIGS. 13 and 14.
- the horizontal axis indicates the width A [mm] of the light shielding part diffusion plate in the z direction
- the vertical axis indicates the rate of increase of the minimum luminance L2 with respect to the light shielding part diffusion plate 114 having a width of 35 mm.
- the minimum luminance L2 increases as the width of the light-shielding part diffusion plate 114 increases, and the increase rate is about 3.3% at a width of 55 mm.
- the configuration of FIG. 14 there is a luminance increasing effect up to a width of about 45 mm, but the minimum luminance increasing effect is saturated when the width is 45 mm or more.
- This phenomenon is divided into an optical action in a direction parallel to the prism formation direction (longitudinal direction) (FIG. 13) and an optical action in a direction perpendicular to the prism formation direction (longitudinal direction) (FIG. 14). To do.
- FIG. 16A shows the state of light in the vicinity of the prism 116 of the light shielding portion diffusing plate 114
- FIG. 16B shows the state of light on the reflection sheet 4.
- the light emitted from the LED 2 at a predetermined emission angle travels in the + z direction, but between the light shielding part diffusion plate 114 and the reflection sheet 4 or the optical sheet part 5 (not shown here) and the reflection sheet 4.
- the light travels in the + z direction while being diffusely reflected between the two.
- the light incident perpendicularly to the prisms 116 is reflected by the light propagation grooves 120 formed between the prisms 116 as shown in FIG. 16A and returns to the reflective sheet 4 side.
- the light returning to the reflection sheet 4 side is diffusely reflected by the reflection sheet 4 and travels in the + z direction as shown in FIG.
- FIG. 17 shows the state of light incident on the prism 117 from an oblique direction.
- the refractive index of the air layer is n1 and the refractive index of the light shielding part diffusion plate is n2 (> n1)
- the light incident on the prism 117 at the incident angle ⁇ in is refracted in the prism 117, and the light shielding part diffusion plate
- the light is refracted again when exiting from 114 and exits from the light-shielding part diffusion plate 114 at an angle of ⁇ out .
- FIG. 18 shows an example in which light and dark unevenness parallel to the x direction exists
- FIG. 19 shows an example in which light and dark unevenness parallel to the z direction exists.
- the light emitting direction of the LED 2 is the + z direction as before.
- the uneven brightness is improved by the effect of spreading the light in the direction perpendicular to the direction of the extension direction of the prism.
- the rate of increase of the minimum luminance L2 is saturated when the width of the light-shielding part diffusion plate 114 is 45 mm or more, but this is the direction of the extension direction (longitudinal direction) of the prism This is because the light diffusion effect in the direction perpendicular to the direction is small.
- the width of the light-shielding part diffuser plate 114 is up to 45 mm, there is an effect of increasing the minimum luminance L2 due to the effect of spreading light, but when the width is 45 mm or more, the influence of the transmittance of the light-shielding part diffuser plate 114 itself increases. The rise effect is saturated.
- the minimum luminance L2 shown in FIG. 15 in the z direction can be increased by either the prism 116 extending in the z direction or the prism 116 extending in the x direction. It is preferable to use the prism 116 having a high light propagation effect on the light source.
- the optimal orientation of the prism can be determined by the arrangement pitch of the LEDs 2 in the horizontal direction (x direction) and / or the arrangement pitch in the vertical direction (z direction).
- the light intensity of an LED is the strongest on the optical axis of the LED (light having an emission angle of 0 degrees) and the weakest in the direction of ⁇ 90 degrees with respect to the optical axis.
- the prisms 116 and 117 are used (that is, the extension direction of the prism) according to the arrangement pitch of the LEDs 2 in the horizontal direction and the vertical direction. Further, which prism is used may be determined depending on the configuration of the optical sheet. For example, it is possible to determine which prism is used in accordance with the direction of improvement in luminance unevenness due to the optical sheet.
- the light exit surface (surface on the optical sheet side) of the light shielding part diffusion plate 114 may be a textured surface (matte surface) or a glossy surface.
- the textured surface is effective in improving luminance unevenness because the light diffusing effect increases, and the glossy surface contributes to improving the luminance because the light propagation effect between the optical sheet 5 and the light-shielding part diffusing plate 114 is increased. .
- the end face of the light shielding part diffusion plate 114 in the + z direction may be a rough surface.
- the end surface rough By making the end surface rough, the light propagated inside the light-shielding part diffusing plate 114 is scattered by hitting the rough surface formed on the end surface, and the luminance near the end surface can be improved.
- the rough surface of the end face may be formed by sand blasting, or may be formed in advance in a mold for molding the light shielding part diffusion plate 114.
- the end surface is a mirror surface, the light propagating through the light shielding portion diffusing plate 114 can reach the lowest luminance portion, and the same effect as in the case of the rough surface can be obtained.
- FIG. 21 the end face of the light shielding part diffusion plate 114 in the + z direction
- a tapered surface facing the optical sheet 5 may be formed at the end portion in the + z direction of the light shielding portion diffusion plate 114.
- the light propagating through the light-shielding part diffusing plate 114 and the light transmitted from the front row (+ z direction side) are diffused by the tapered surface and guided so that the light reaches a farther direction.
- the brightness increase effect of a desired position is acquired by changing a taper angle.
- the taper angle may be appropriately changed depending on the pitch of the LEDs 2 and the like.
- Example 6 the light-shielding part diffusion plate 114 of Example 5 divided into a plurality of parts was used as the optical element. However, the single-piece light-shielding part diffusion plate 1 described in Example 1 or the like may be used. .
- the present embodiment it is possible to reduce spatial color unevenness and luminance unevenness on the light exit surface of the illumination device. Further, luminance unevenness due to thermal expansion can be reduced.
- the prisms 116 and 117 are provided on the LED2 side surface of the light shielding part diffusion plate 114 (light incident surface of the light shielding part diffusion plate 114).
- the present invention is not limited to this. You may provide in the light-projection surface of the light-shielding part diffuser plate 114, and you may provide in both a light-incidence surface and a light-projection surface.
- the light propagation groove 120 has a triangular cross section. However, the present invention is not limited to this.
- a lenticular groove having a semicircular cross section a trapezoidal trapezoidal groove having a cross section, a rectangular groove having a quadrangular cross section, or a groove having a multi-step surface may be used.
- Any light propagation function as shown in FIG. 16 (a) by refraction or reflection may be used.
- FIG. 23A is a partially enlarged view of the illumination device according to the present embodiment as viewed from the light exit surface side (+ y direction side), and FIG. 24B is a cross-sectional view thereof (cross section of the xy plane).
- a prism 116 extending in the light emission direction (z direction) of the LED is used as the prism.
- the single-piece light-shielding part diffusion plate 1 is used as an optical element, a divided light-shielding part diffusion plate 114 may be used.
- the light-shielding part diffuser plate 1 is supported from the back side thereof by, for example, a conical pin 23.
- the light shielding pattern 6 is not shown directly above all the LEDs 2 in this figure, and a part of the illustration is omitted.
- the arrangement pitch of the light propagation grooves 120 or the prisms 116 for forming the grooves in the x direction is P
- the width in the longitudinal direction of the light emitting surface of the LED 2 is La
- the LED 2 In this embodiment, the following expression 2 is satisfied, where Lp is the arrangement pitch in the X direction and Na is the number of the light propagation grooves 120 within the width La.
- the light emitting surface width La of the LED 2 is defined in detail as shown in FIG.
- the arrangement pitch P in the x direction of the light propagation grooves 120 is, for example, 30 to 70 mm
- the width La in the longitudinal direction of the light emitting surface of the LED 2 is, for example, 3 mm
- the arrangement pitch P in the x direction of the light propagation grooves 120 is, for example,. It is about 01 to 0.05 mm.
- the groove arrangement pitch P is set so that the number Na of light propagation grooves 120 within the width La is smaller than the total number of light propagation grooves 120 at the arrangement pitch Lp of the LEDs 2.
- the number of light propagation grooves 120 that can divide the width La of the light emitting surface of the LED 2 into a plurality of portions can be arranged even if the arrangement pitch Lp of the LEDs 2 is increased.
- the hot spot immediately above the LED 2 is dispersed or diffused by the light propagation groove 120, and the light intensity of the hot spot can be reduced to improve the luminance uniformity.
- the luminance uniformity in the z direction can also be improved.
- the height of the prism 116 forming the light propagation groove 120 in the y direction is a, the light exit surface of the light-shielding part diffusion plate 1 and the optical sheet 5
- this embodiment satisfies the following Expression 3. It is configured.
- the height a of the prism 116 is, for example, 0.05 to 0.5 mm, and the diffusion distance h is, for example, about 0.5 to 10 mm.
- the diffusion distance h is equal to or greater than the height a of the prism 116 as described above, the light propagation groove 120 formed by the prism 161 is reflected or refracted and propagates in the light shielding portion diffusion plate 1 while traveling in the + z direction. Can be diffused satisfactorily in the space defined by the diffusion distance h (the space between the light shielding part diffusion plate 1 and the optical sheet 5). Further, the light reflected by the optical sheet 5 and incident on the light shielding part diffusion plate 1 and reflected by the light shielding part diffusion plate 1 or emitted from the light shielding part diffusion plate 1 is also diffused well in the space defined by the diffusion distance h. can do.
- the luminance distribution in the exit surface from the light shielding part diffusion plate 1 can be made uniform or smooth, and for example, hot spots directly above the LEDs 2 can be reduced.
- light and dark unevenness similar to the arrangement of the prisms that may occur due to the provision of the prism 161 (which appears more easily as the prism height a is higher) diffuses well in the space defined by the diffusion distance h. Can be made inconspicuous.
- FIG. 24 is a partially enlarged view centered on one light-shielding pattern 6 when the illumination device according to the present embodiment is viewed from the light emission surface side (+ y direction side), and the right view is a cross-sectional view thereof.
- the lower diagram shows a partially enlarged view of dots in the light shielding pattern 6.
- a prism 116 extending in the light emission direction (z direction) of the LED is used as the prism.
- the single-piece light-shielding part diffusion plate 1 is used as an optical element, a divided light-shielding part diffusion plate 114 may be used.
- the prism pitch is small, the light dispersion can be made fine.
- the print dot diameter is 0.2 mm to 0.5 mm or about 1 mm, so if the prism is made too small, the dispersion width of the light becomes narrow, and the effect of such dispersion (dots (Shadow prevention by shadowing) will be reduced. Also, it is difficult to form a prism (light propagation groove). Therefore, in order to obtain the above effects and from the viewpoint of prism formation, the lower limit value of the parallel pitch P of the prisms 116 is preferably about 0.01 mm.
- the arrangement pitch in the x direction (direction orthogonal to the light emission direction of the LED) of the light propagation grooves 120 or the prisms 116 for forming the light propagation grooves 120 is P
- the minimum dot pitch in the light shielding pattern 6 is Pd.
- the present embodiment is configured to satisfy the following Expression 5. Yes.
- the arrangement pitch P of the prisms 116 is made smaller than the minimum dot pitch, so that the shadow of the outline of the dots is formed by reflection or refraction by the two prism surfaces of the prism 116. Light can be dispersed and the shadows of the dots can be made difficult to see.
- the arrangement pitch P of the prisms 116 is made larger than the minimum gap distance so that light leaking from the gap is adjacent to the gap. Therefore, the luminance uniformity can be further improved.
- Example 9 of the present invention will be described with reference to FIG.
- the light emission directions of the LEDs 2 arranged in a line are all the same direction (+ z direction).
- the light emission directions are reversed for every other LED ( -Z direction). That is, in this embodiment, the LEDs 2 that emit light in the + z direction and the LEDs 2 that emit light in the ⁇ z direction are alternately arranged along the x direction.
- the light emitting directions of the LEDs 2 are the + z direction and the ⁇ z direction, but they may be the + x direction and the ⁇ x direction.
- the reflection sheet 4 is provided on the inner surface of the chassis 7. As shown in the figure, the reflection sheet is inclined so as to incline in the light emitting direction (paper surface) of the illumination device as it goes to the periphery of the illumination device. Is provided. Therefore, the light emitted from the LED 2 is reflected by the slope of the reflection sheet 4 and propagates in the direction of the light propagation groove of the light shielding portion diffusion plate 1, and passes through the light shielding portion diffusion plate 1 when the incident angle becomes appropriate. Irradiated from the exit surface. As a result, the light propagates to the periphery of the lighting device, and the brightness of the tip as well as the center can be improved.
- Examples 1 to 9 described above only one light-shielding part diffusion plate 1 is used.
- two light-shielding part diffusion plates 1 can be stacked in the + y direction, for example.
- the light-shielding part diffusion plate 1 on the lower side is the light incident side
- the light-shielding part diffusion plate 1 on the upper side is the light exit surface. It is preferable to provide on the side. However, both may be provided on the light incident side, or both may be provided on the light exit side.
- the lighting device is applied to the backlight of the video display device (liquid crystal display device)
- the present invention is not limited to this.
- the illuminating device according to the present embodiment can be applied as, for example, indoor lighting, elevators, or interior lighting, and can also be used as lighting for signboards.
- SYMBOLS 1 Optical element, 2 ... LED, 3 ... LED board
Abstract
Description
ここで、ΔLは膨張量、αは線膨張係数、Lは物体の長さ、ΔTは温度上昇値であり、αは物体固有の物性値である。つまり膨張量ΔLは、物体の長さLが大きいほど大きくなり、物体周囲の温度上昇ΔTが大きい程大きくなる。本実施例では、光学素子として実施例1~4で説明した1枚構成の遮光部拡散板1よりも小さい遮光部拡散板114を使用しているため、熱膨張量、即ち撓みが小さくなり、熱によるLED2と遮光部拡散板114との距離の変化を低減することができる。
ここで、光伝播溝120のx方向の配列ピッチPは、例えば30~70mm、LED2の発光面の長手方向の幅Laは例えば3mm、光伝播溝120のx方向の配列ピッチPは例えば0.01~0.05mm程度である。このように、LED2の配列ピッチLpにおける光伝播溝120の全本数よりも幅La内における光伝播溝120の本数Naが小さくなるように溝の配列ピッチがP設定される。
ここで、プリズム116の高さaは例えば0.05~0.5mmであり、拡散距離hは例えば0.5~10mm程度である。
この条件を満足すれば、遮光パターン6のドットが連続して配列されている場合、例えばドットの間の空間が3個のドットより小さい距離の場合には、その空間にプリズム116が少なくとも1本以上配置されることになる。このため、図24のに示されるように、遮光パターン6のドット間において、プリズム116の2つの面により光が半分ずつ分散(図中Li2、Li3)されることになる。また遮光パターン6のドットで反射された光はプリズム116の面で反射されて再度出射される(図中Li1)これらの光は、ドットの上方をカバーする進行して出射するため、照明装置の出射面側から見たときにドットによる影が見え辛くなる。当然、プリズムピッチが小さければ、上記光の分散は細かくできる。しかしながら、現在の印刷機では、印刷ドット径が0.2mm~0.5mm、或いは1mm程度が最小であるため、プリズムを小さくしすぎると上記光の分散幅が狭くなり、かかる分散による効果(ドットによる影の視認防止)が低下することとなる。またプリズム(光伝播溝)形成も困難となる。従って、上記効果を得るため、及びプリズム形成上の観点から、プリズム116の並列ピッチPの下限値は、約0.01mmとするのが好ましい。
上記式5の条件を満たせば、プリズム116の配列ピッチPはドットの最小ピッチよりも小くしているため、プリズム116の2つのプリズム面による反射又は屈折作用によりドットの輪郭の陰影を形成するような光を分散することができ、ドットの陰影を見え難くすることができる。遮光パターン6におけるドット間の最小隙間から光を漏らす場合には、プリズム116の配列ピッチPが当該最小隙間距離よりも大きくすることにより、当該隙間から漏れた光を当該隙間に隣接するそれぞれのドットの陰影に被せることができるため、輝度均一性をより一層向上することができる。
Claims (20)
- 光を照射するための照明装置において、
ベースシャーシと、前記ベースシャーシ上に設けられた反射シートと、該反射シートから前記照明装置の出射面と直交する方向に所定間隔離して配置された光学素子と、前記反射シートと前記光学素子との間の空間において、該照明装置の光の出射面と平行な方向に光を出射するための、一列状に配列された複数のLEDと、前記光学素子の出射面側に設けられた光学シートと、を備え、
前記光学素子の光出射面側の各LEDと対応する位置に遮光パターンが設けられており、
前記遮光パターンは、複数の遮光層を積層して構成されており、該遮光層のうち最も光学素子側の遮光層が、他の遮光層の少なくとも一つよりも白色の割合が高いことを特徴とする照明装置。 - 請求項1に記載の映像表示装置において、前記LEDは蛍光体を含み、該蛍光体の励起により白色光を放出する構成であることを特徴とする照明装置。
- 請求項1に記載の照明装置において、前記複数の遮光層のうち最も前記光学素子側に位置する遮光層は白色インクで構成されており、他の遮光層の少なくとも一つは、白色と青色の混色インク、または白色、青色及び黒色の混合インクであるであることを特徴とする照明装置。
- 請求項1に記載の照明装置において、前記遮光パターンは少なくとも3層の遮光層を含み、該3層の遮光層を、前記光学素子側から前記光学シート側にかけて順に1層目、2層目、3層目としたとき、前記1層目は白色インクで構成され、前記2層目と前記3層目のいずれか一方は、白色インクで構成され、他方は白色と青色の混合インク、または白色、青色及び黒色の混合インクで構成されることを特徴とする照明装置。
- 請求項1に記載の照明装置において、前記遮光パターンは少なくとも2層の遮光層を含み、該2層の遮光層のうち前記光学素子に最も近い遮光層は白色インクで構成され、他の遮光層は白色と青色の混合インク、又は白色、青色及び黒色の混合インクで構成されることを特徴とする照明装置。
- 請求項5に記載の照明装置において、前記遮光パターンは、前記LEDの直上に対応して設けられた長円又は楕円形状の第1パターンと、該第1パターンの周囲に設けられた複数のドットで構成され、かつ該ドットの単位面積当たりの密度が第1パターンから離れるに従い低下するように構成された第2パターンとを含み、
前記白色インクで構成された前記光学素子に最も近い遮光層は、前記第1パターン及び第2パターンを有し、前記混合インクで構成された他の遮光層は、前記第1パターンを有することを特徴とする照明装置。 - 請求項1に記載の照明装置において、前記光学素子は拡散板であることを特徴とする照明装置。
- 請求項7に記載の照明装置において、前記一列状に配列された複数のLEDを実装するLED基板を有し、該LED基板がLEDの光出射方向に沿って複数配列されており、
前記LED基板のそれぞれに対応して1つまたは複数の前記拡散板が設けられていることを特徴とする照明装置。 - 請求項8に記載の照明装置において、前記各拡散板の前記LED側の面に、複数のプリズムが形成されていることを特徴とする照明装置。
- 請求項9に記載の照明装置において、前記プリズムは、前記LEDの光出射方向と直交する断面が三角形状で、かつ前記LEDの光出射方向に延びて形成される、または、前記LEDの光出射方向と平行で且つ前記光学素子の面と直交する断面が三角形状で、かつ前記LEDの光出射方向と直交する方向に延びて形成されることを特徴とする照明装置。
- 請求項9に記載の照明装置において、前記拡散板の、前記LEDの光出射方向側の端面あるいは端部に粗面、鏡面またはテーパ面を形成したことを特徴とする照明装置。
- 請求項9に記載の照明装置において、前記拡散板の前記プリズムが形成されていない面をシボ面または光沢面としたことを特徴とする照明装置。
- 光を照射するための照明装置において、
ベースシャーシと、前記ベースシャーシ上に設けられた反射シートと、該反射シートから前記照明装置の出射面と直交する方向に所定間隔離して配置された光学素子と、前記反射シートと前記光学素子との間の空間において、該照明装置の光の出射面と平行な方向に光を出射するための、一列状に配列された複数のLEDと、前記光学素子の出射面側に設けられた光学シートと、前記一列状に配列された複数のLEDを実装するLED基板と備え、
前記拡散板の一方の面の、前記各LEDと対応する位置のそれぞれに遮光パターンが設けられ、他方の面に、前記LEDの光出射方向と平行な方向に伸びる光伝播溝が形成されていることを特徴とする照明装置。 - 請求項13に記載の照明装置において、前記拡散板の一方の面は該拡散板の光出射面であり、他方の面は該拡散板の光入射面であり、前記拡散板の光出射面に前記遮光パターンが設けられ、前記拡散板の光入射面に前記光伝播溝を形成するためのプリズムが設けられていることを特徴とする照明装置。
- 請求項14に記載の照明装置において、前記光伝播溝の、LEDの光出射方向と直交する方向の配列ピッチをP、LEDの発光面の長手方向の幅をLa、LEDの配列ピッチをLp、上記幅La内の光伝播溝の本数をNaとしたとき、
Lp/P≧Na≧Lp/La(但しLp>La、Lp>P)
を満足することを特徴とする照明装置。 - 請求項14に記載の照明装置において、前記プリズムの高さをa、前記拡散板の光出射面と前記光学シートの入射面との距離をhとしたとき、
h≧a
を満足することを特徴とする照明装置。 - 請求項14に記載の照明装置において、前記遮光パターンは複数のドットを有し、前記光伝播溝のLEDの光出射方向と直交する方向の配列ピッチをP、前記遮光パターンのドットの最小サイズをDaとしたとき、
3×Da>P≧Da/100
を満足することを特徴とする照明装置。 - 請求項14に記載の照明装置において、前記遮光パターンは複数のドットを有し、前記光伝播溝のLEDの光出射方向と直交する方向の配列ピッチをP、前記遮光パターンのドットの最小ピッチをPd、前記遮光パターンのドット間の最小隙間距離をPsとしたとき、前記遮光パターンの透過率をTrが0.1%≦T<50%の場合に、
Pd≧P≧Ps
を満足することを特徴とする照明装置。 - 請求項14に記載の照明装置において、光出射方向が互いに異なる2つのLEDが一列状に交互に配置されており、前記反射シートは、前記照明装置の光出射方向に傾斜するようなスロープが設けられていることを特徴とする照明装置。
- 請求項1~19に記載の照明装置をバックライトとして用い、該バックライトからの光を液晶パネルに照射して映像を表示するようにした映像表示装置。
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018056367A (ja) * | 2016-09-29 | 2018-04-05 | 日亜化学工業株式会社 | 発光装置 |
WO2018173931A1 (ja) * | 2017-03-22 | 2018-09-27 | シャープ株式会社 | 光学シート及びバックライト |
CN110431479A (zh) * | 2017-03-23 | 2019-11-08 | 夏普株式会社 | 背光源及背光源的制造方法 |
JP7372523B2 (ja) | 2019-08-27 | 2023-11-01 | 日亜化学工業株式会社 | 発光装置 |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20140132913A (ko) * | 2013-05-09 | 2014-11-19 | 삼성전자주식회사 | 디스플레이 장치 |
US9803833B2 (en) * | 2013-12-03 | 2017-10-31 | X Development Llc | Multi-aperture illumination layer for tileable display |
KR20180011398A (ko) * | 2016-07-21 | 2018-02-01 | 삼성디스플레이 주식회사 | 표시 장치 및 이의 제조 방법 |
JP2019083103A (ja) * | 2017-10-30 | 2019-05-30 | シャープ株式会社 | 照明装置および画像表示装置 |
US20200073174A1 (en) * | 2018-08-30 | 2020-03-05 | Sharp Kabushiki Kaisha | Lighting device and display device provided with the same |
CN110379912B (zh) * | 2019-06-28 | 2021-06-22 | 佛山市国星光电股份有限公司 | Led器件、背光模组和显示装置 |
KR102629991B1 (ko) | 2019-07-08 | 2024-01-29 | 삼성전자주식회사 | 디스플레이 장치 |
TW202210605A (zh) * | 2020-09-14 | 2022-03-16 | 李崇華 | 白光發光二極體及包含其之背光模組與顯示裝置 |
KR102601190B1 (ko) * | 2021-06-30 | 2023-11-09 | 엘지전자 주식회사 | 디스플레이 디바이스 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008241936A (ja) * | 2007-03-26 | 2008-10-09 | Toppan Printing Co Ltd | ディスプレイ、ディスプレイ用バックライトユニット、光学シート、及び光学シートの製造方法 |
JP2008281647A (ja) * | 2007-05-08 | 2008-11-20 | Citizen Electronics Co Ltd | 光学部材及びバックライトユニット並び表示装置 |
JP2009110696A (ja) * | 2007-10-26 | 2009-05-21 | Opt Design:Kk | 面照明ユニット、面照明光源装置、および面照明装置 |
JP2009187904A (ja) * | 2008-02-08 | 2009-08-20 | Toppan Printing Co Ltd | 光源ユニット、バックライトユニット及びディスプレイ装置 |
JP2012008280A (ja) * | 2010-06-23 | 2012-01-12 | Nippon Zeon Co Ltd | 液晶表示装置 |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008050504A1 (fr) * | 2006-10-27 | 2008-05-02 | Sharp Kabushiki Kaisha | Dispositif d'éclairage et affichage à cristaux liquides |
JP4813383B2 (ja) * | 2007-01-22 | 2011-11-09 | アルプス電気株式会社 | 導光シート |
DE102008021721A1 (de) | 2007-05-08 | 2008-11-27 | Citizen Electronics Co., Ltd., Fujiyoshida-shi | Optisches Bauteil, Hintergrundbeleuchtungseinheit und Anzeigevorrichtung |
JP2010186679A (ja) * | 2009-02-13 | 2010-08-26 | Oji Paper Co Ltd | 面光源装置および面光源装置用光学部材の製造方法 |
JP2010218972A (ja) * | 2009-03-18 | 2010-09-30 | Minebea Co Ltd | 面状照明装置 |
CN102341740B (zh) * | 2009-06-22 | 2015-09-16 | 财团法人工业技术研究院 | 发光单元阵列、其制造方法和投影设备 |
CN102483542B (zh) * | 2009-08-27 | 2015-01-21 | Lg电子株式会社 | 背光单元和显示装置 |
JP2011216322A (ja) | 2010-03-31 | 2011-10-27 | Sony Corp | 発光装置およびこれを用いた表示装置 |
KR101692509B1 (ko) * | 2010-11-02 | 2017-01-03 | 엘지이노텍 주식회사 | 디스플레이 장치 |
CN102741713B (zh) * | 2010-11-02 | 2015-06-10 | 大日本印刷株式会社 | 光学组件以及显示装置 |
JP2012128016A (ja) | 2010-12-13 | 2012-07-05 | Nippon Zeon Co Ltd | 液晶表示装置 |
KR101287493B1 (ko) * | 2010-12-23 | 2013-07-18 | 엘지이노텍 주식회사 | 백라이트유닛 및 이를 이용한 액정표시장치 |
-
2012
- 2012-07-25 WO PCT/JP2012/068752 patent/WO2014016913A1/ja active Application Filing
- 2012-07-25 JP JP2014526649A patent/JP5886427B2/ja active Active
- 2012-07-25 CN CN201280074865.1A patent/CN104508351B/zh active Active
- 2012-07-25 US US14/416,337 patent/US9651205B2/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008241936A (ja) * | 2007-03-26 | 2008-10-09 | Toppan Printing Co Ltd | ディスプレイ、ディスプレイ用バックライトユニット、光学シート、及び光学シートの製造方法 |
JP2008281647A (ja) * | 2007-05-08 | 2008-11-20 | Citizen Electronics Co Ltd | 光学部材及びバックライトユニット並び表示装置 |
JP2009110696A (ja) * | 2007-10-26 | 2009-05-21 | Opt Design:Kk | 面照明ユニット、面照明光源装置、および面照明装置 |
JP2009187904A (ja) * | 2008-02-08 | 2009-08-20 | Toppan Printing Co Ltd | 光源ユニット、バックライトユニット及びディスプレイ装置 |
JP2012008280A (ja) * | 2010-06-23 | 2012-01-12 | Nippon Zeon Co Ltd | 液晶表示装置 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018056367A (ja) * | 2016-09-29 | 2018-04-05 | 日亜化学工業株式会社 | 発光装置 |
JP2021101474A (ja) * | 2016-09-29 | 2021-07-08 | 日亜化学工業株式会社 | 発光装置 |
JP7125636B2 (ja) | 2016-09-29 | 2022-08-25 | 日亜化学工業株式会社 | 発光装置 |
WO2018173931A1 (ja) * | 2017-03-22 | 2018-09-27 | シャープ株式会社 | 光学シート及びバックライト |
CN110431479A (zh) * | 2017-03-23 | 2019-11-08 | 夏普株式会社 | 背光源及背光源的制造方法 |
CN110431479B (zh) * | 2017-03-23 | 2022-01-04 | 夏普株式会社 | 背光源及背光源的制造方法 |
JP7372523B2 (ja) | 2019-08-27 | 2023-11-01 | 日亜化学工業株式会社 | 発光装置 |
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