Patent Application
20190204678
The present invention relates to lighting devices and display devices.
As an example of conventional liquid crystal display devices, one described in the following PTL 1 is known. In this liquid crystal display device described in PTL 1, in fixing both of a liquid crystal panel and an optical film included in a backlight by a light-shielding sheet, an opening of the light-shielding sheet is formed so as to be larger than a display part of the liquid crystal display panel and the outer shape of the optical film is formed so as to be larger than the display part of the liquid crystal display panel and smaller than the opening of the light-shielding sheet, a protruding piece is provided to be fixedly attached to the outer edge of the optical film.
In the above-described liquid crystal display device described in PTL 1, one protruding piece provided to the outer edge of the optical film is fixedly attached as squeezing below the light-shielding sheet. However, when the size of the optical film is increased as the size of the liquid crystal display device is increased, if the optical film is fixed by one protruding piece as described above, there is a concern about an occurrence of a sag or the like due to its own weight. To prevent this, it is considered to adopt a configuration in which, for example, the optical film is supported as being suspended. However, when a plurality of optical films with different coefficients of linear expansion are laminated and arranged, if adhesion occurs between support structures of the overlapping optical films, the support structures cannot make relative displacement with thermal expansion and, as a result, deformation such as a wrinkle may occur to an optical film.
The present invention has been completed based on circumstances as described above, and has an object of making each sheet member less deformable.
A lighting device of the present invention includes: a first sheet member having a surface parallel to a first direction and a second direction orthogonal to each other; a first sheet support part which supports one end side of the first sheet member in the first direction; a first supported part provided on the one end side of the first sheet member and close to an end with respect to a center position in the second direction, having a first opening which the first sheet support part passes through, and supported by the first sheet support part; a second sheet member having a surface parallel to the surface of the first sheet member, stacked on the first sheet member, and having a coefficient of linear expansion different from a coefficient of linear expansion of the first sheet member; a second sheet support part which supports the one end side of the second sheet member; and a second supported part provided on the one end side of the second sheet member and close to the end with respect to the center position in the second direction and supported by the second sheet support part, the second supported part disposed at a position not superposed on at least the first opening.
With this, the first sheet member is supported in the first direction, with the first supported part provided on one end side in the first direction and close to the end with respect to the center position in the second direction being supported by the first sheet support part where the first supported part passes through the first opening. The second sheet member stacked on the first sheet member is supported in the first direction, with the second supported part provided on one end side in the first direction and close to the end with respect to the center position in the second direction being supported by the second sheet support part. Each sheet member thermally expand in the first direction and the second direction as the temperature of the temperature environment is increased. In the following, the operation regarding the second direction is descried in detail. When each sheet member thermally expands in the second direction, each supported part is relatively displaced in the second direction with respect to each sheet support part accordingly. As described above, since the first sheet member and the second sheet member have different coefficients of linear expansion, the first supported part and the second supported part have different deformation amounts in the second direction with thermal expansion.
The first opening is formed in at least the first supported part, and there is a possibility that a protrusion such as a burr is formed on its opening edge due to a reason in manufacture. If this protrusion is caught on the second supported part, the first supported part and the second supported part may stick to each other to inhibit relative displacement. By contrast, the second supported part is disposed at a position not superposed on at least the first opening, even if a protrusion such as a burr is formed on the opening edge of the first opening, the situation hardly occurs in which that protrusion is caught on the second supported part. With this, the first supported part and the second supported part hardly stick to each other. Therefore, even if the displacement amounts of the first supported part and the second supported part in the second direction with thermal expansion are different, relative displacement between the first supported part and the second supported part is allowed, and thus deformation such as a wrinkle hardly occurs in each sheet member.
The following structures are preferable as embodiments of the present invention.
(1) The second supported part has a second opening which the second sheet support part passes through. With this, the second sheet member is supported in the first direction, with the second supported part being supported by the second sheet support part which passing through the second opening. In addition to the first opening of the first supported part, the second opening of the second supported part may have a protrusion such as burr formed due to a reason in manufacture. However, the second opening is formed in the second supported part so as not to be superposed on the first opening, and both of the openings are arranged so as not to be superposed each other. Therefore, when the protrusion is formed on the opening edge of any first opening, the situation hardly occurs in which that protrusion is caught on the opening edge of the second opening. Conversely, when the protrusion is formed on the opening edge of the second opening, the situation hardly occurs in which that protrusion is caught on the opening edge of the first opening. With this, the first supported part and the second supported part hardly stick to each other, and each sheet member is made further less deformable.
(2) The second supported part has the second opening disposed at a position not superposed on the first supported part. With this, when a protrusion such as a burr occurs on the opening edge of the second opening, the situation hardly occurs in which that protrusion is caught on the first supported part. With this, the first supported part and the second supported part is prevented from sticking to each other, and each sheet member is made further less deformable.
(3) The second supported part is disposed at a position not superposed on the first supported part. With this, when a protrusion such as a burr is formed on the outer edge of any supported part due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the outer edge of any supported part or the opening edge of the first opening. With this, the first supported part and the second supported part is prevented from sticking to each other, and each sheet member is made less deformable.
(4) The device includes: a center-side sheet support part which supports a center side in the second direction on the one end side of the first sheet member and the second sheet member; a first center-side supported part provided on the one end side of the first sheet member and at a center position in the second direction, having a first center-side opening which the center-side sheet support part passes through, and supported by the center-side sheet support part; and a second center-side supported part provided on the one end side of the second sheet member and at the center position in the second direction, superposed on the first center-side opening, having a second center-side opening which the center-side sheet support part passes through, and supported by the center-side sheet support part. With this, the first center-side supported part and the second center-side supported part are provided with the first center-side opening and the second center-side opening superposed each other, respectively, and the common center-side sheet support part passes through these first center-side opening and second center-side opening, and thereby the first sheet member and the second sheet member is supported on the center side in the second direction. In this manner, with the center-side sheet support part being shared in common, the structure is simplified. The first center-side supported part and the second center-side supported part are portions are portions serving as origins when each sheet member extends along the second direction at the time of thermal expansion, therefore hardly make relative displacement with thermal expansion in the second direction with respect to the center-side sheet support part, and are thus prevented from causing deformation such as a wrinkle in each sheet member.
(5) Either one of the first sheet member and the second sheet member serves as a heavy sheet member which is relatively heavy and another one serves as a light-weight sheet member which has a relatively light weight, and the heavy sheet member has a larger number of installations of the first supported part or the second supported part than the light-weight sheet member. The heavy sheet member is relatively heavy compared with the light-weight sheet member, and therefore the loads on the first supported part or the second supported part as a support location by the first sheet support part or the second sheet support part is large. In this regard, the heavy sheet member has the larger number of installations of the first supported parts or the second supported parts than the light-weight sheet member. Therefore, the loads on the first supported parts or the second supported parts are distributed. With this, the situation hardly occurs in which any first supported part or second supported part is damaged or the like by the weight of the heavy sheet member, and stable support can be achieved.
(6) The second sheet member has the coefficient of linear expansion smaller than the coefficient of linear expansion of the first sheet member, and the second supported part forms a non-opening protrusion piece shape protruding from an outer edge of the second sheet member along the second direction. With this, the second supported part forms a protrusion piece shape protruding from the outer edge of the second sheet member along the second direction and is thus supported by the second sheet support part even in the case of non-opening. The size of the second supported part is decreased by being non-opening. Also, the second sheet member has a coefficient of linear expansion smaller than that of the first sheet member, and therefore the displacement amount in the second direction with thermal expansion regarding the second supported part is relatively small, compared with the displacement amount regarding the first supported part. This is suitable for making the lighting device as a narrow picture frame.
(7) Either one of the first sheet member and the second sheet member serves as a thick sheet member which is relatively thick and another one serves as a thin sheet member which is relatively thin, and the thin sheet member is disposed so as to be stacked on a side of the thick sheet member opposite to an output light side. With this, the thin sheet member is relatively thin, compared with the thick sheet member, and therefore deformation such as a wrinkle intrinsically tends to occur. Therefore, by disposing the thin sheet member so as to be stacked on the side of the thick sheet member opposite to the output light side as described above, even in the event of that deformation such as a wrinkle occurs in the thin sheet member, that deformation is hardly visually recognized from a user of the lighting device.
(8) The first sheet member and the second sheet member serve as a first optical sheet and a second optical sheet, respectively, each of which provides optical action to light, the lighting device comprises a frame-shaped member which forms a frame shape so as to extend along an outer edge of the first optical sheet and the second optical sheet and also delimits an effective output light area of the first optical sheet and the second optical sheet, and the first sheet support part and the second sheet support part are provided to the frame-shaped member. With this, the first optical sheet and the second optical sheet in which the effective output light area is delimited by the frame-shaped member are supported by the first sheet support part and the second sheet support part provided to the frame-shape member in the first direction, and therefore the arrangement of the effective output light area in the first optical sheet and the second optical sheet becomes appropriate. Also, since deformation such as a wrinkle hardly occurs in the first optical sheet and the second optical sheet, unevenness hardly occurs in the output light amount from the effective output light area, and the luminance distribution of emission light is made uniform.
(9) The device includes: a third sheet member having a surface parallel to the surface of the first sheet member, stacked on a side of the second sheet member opposite to the first sheet member side, and having a coefficient of linear expansion different from at least the coefficient of linear expansion of the first sheet member; a third sheet support part which supports the one end side of the third sheet member; and a third supported part provided on the one end side of the third sheet member and close to an end with respect to a center position in the second direction and supported by the third sheet support part, the third supported part disposed at a position not superposed on the first supported part and the second supported part. With this, the third sheet member stacked on the side of the second sheet member opposite to the first sheet member side is supported in the first direction, with the third supported part provided on one end side in the first direction and close to the end with respect to the center position in the second direction being supported by the third support part. Since the third supported part is disposed at the position not superposed on the first supported part and the second supported part, even if a protrusion such as a burr is formed on the outer edge of any supported part or the opening edge of the first opening due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the outer edge of any supported part or the opening edge of the first opening. With this, the third supported part is prevented from sticking to the first supported part and the second supported part, and each sheet member is made further less deformable.
(10) At least either one of the second sheet member and the third sheet member serves as a small-coefficient-of-linear-expansion sheet member having the coefficient of linear expansion smaller than the coefficient of linear expansion of the first sheet member, and at least either one of the second supported part and the third supported part included in the small-coefficient-of-linear-expansion sheet member forms a non-open protrusion piece shape protruding from an outer edge of the small-coefficient-of-linear-expansion sheet member along the second direction. With this, at least either of the second supported part and the third supported part included in the small-coefficient-of-linear-expansion sheet member forms protrusion piece shape protruding from the outer edge of the small-coefficient-of-linear-expansion sheet member along the second direction, and is therefore supported by at least either one of the second sheet support part and the third sheet support part even in the case of non-opening. With at least either one of the second supported part and the third supported part being made with non-opening, the size in the second direction is decreased. Since the small-coefficient-of-linear-expansion sheet member has a coefficient of linear expansion smaller than that of the first sheet member, the displacement amount in the second direction with thermal expansion regarding at least either of the second supported part and the third supported part is relatively small, compared with the displacement amount regarding the first supported part. This is suitable for making the lighting device as a narrow picture frame.
(11) The device includes: a third sheet member having a surface parallel to the surface of the first sheet member, stacked on a side of the second sheet member opposite to the first sheet member side, and having a coefficient of linear expansion different from at least the coefficient of linear expansion of the first sheet member; and a third supported part provided on the one end side of the third sheet member and at a position superposed on the first supported part, the third supported part having a third opening superposed on the first opening, the third opening which the first sheet support part passes through, and supported by the first sheet support part. With this, the third sheet member stacked on the side of the second sheet member opposite to the first sheet member side is supported in the first direction, with the third supported part provided on one end side in the first direction and at the position superposed on the first supported part being supported by the first sheet support part passing through the third opening superposed on the first opening part. Since the first supported part and the third supported part are supported by the common first sheet support part, this is suitable for simplification of the structure. Since the second sheet member is interposed between the first sheet member and the third sheet member, even if a protrusion such as a burr is formed on the opening edge of the first opening or the opening edge of the third opening due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the third supported part or the first supported part where that protrusion is superposed.
(12) The device includes: a third sheet member having a surface parallel to the surface of the first sheet member, stacked on a side of the second sheet member opposite to the first sheet member side, and having a coefficient of linear expansion equivalent to the coefficient of linear expansion of the second sheet member; and a third supported part provided on the one end side of the third sheet member and at a position superposed on the second supported part, the third supported part supported by the second sheet support part. With this, the third sheet member stacked on the side of the second sheet member opposite to the first sheet member side is supported in the first direction, with the third supported part provided on one end side in the first direction and at the position superposed on the second supported part being supported by the second sheet support part. Since the second supported part and the third supported part being supported by the common second sheet support part, this is suitable for simplification of the structure. Since the coefficients of linear expansion of the second sheet member and the third sheet member are equivalent to each other, relative displacement with thermal expansion hardly occurs between the second supported part and the third supported part. Therefore, even if a catch occurs between the second supported part and the third supported part, deformation such as a wrinkle hardly occurs in the second sheet member and the third sheet member.
Next, to solve the above-described problem, the display device of the present invention includes the above-described lighting device and a display panel which displays an image by using light applied from the lighting device. According to the display device structured as described above, each sheet member included in the lighting device is made less deformable, and therefore display performance thus excellent.
According to the present invention, each sheet member can be made less deformable.
A first embodiment of the present invention is described with reference to
A television receiving device 10TV according to the present embodiment includes, as depicted in
Next, the liquid crystal panel 11 and the backlight device 12 configuring the liquid crystal display device 10 are sequentially described. Of these, the liquid crystal panel (display panel) 11 forms a laterally-elongated quadrate shape, in a planar view, and is assumed to be configured with a pair of glass substrates laminated in a state of being separated across a predetermined gap and with a liquid crystal layer (not depicted) enclosed between both glass substrates, the liquid crystal layer containing liquid crystal molecules as substances whose optical characteristics change with the application of an electric field. On an inner surface side of one glass substrate (array substrate, active matrix substrate), switching elements (for example, TFTs) connected to source lines and gate lines orthogonal to each other and pixel electrodes disposed in a quadrate area surrounded by the source lines and the gate lines to be connected to the switching elements are arranged in a matrix shape in a planar manner. Also, an alignment layer and so forth are provided. On an inner surface side of the other glass substrate (counter substrate, CF substrate), color filters are provided, with colored parts such as R (red), G (green), and B (blue) arranged in a matrix shape with a predetermined array in a planar manner. Also, light-shielding layers (black matrixes) disposed between the colored parts to form a lattice, mat-shaped counter electrodes opposed to the pixel electrodes, an alignment layer, and so forth are provided. On an outer surface side of each of both glass substrates, a polarizing plate is disposed. Furthermore, the long side direction of the liquid crystal panel 11 matches the X axis direction, and the short side direction thereof matches the Y axis direction. Furthermore, the thickness direction matches the Z axis direction.
The backlight device 12 includes, as depicted in
The chassis 14 is made of metal, is formed of, as depicted in
The optical sheet 15 forms, as depicted in
Although detailed depiction is omitted, the reflective polarizing sheet 27 is configured of a reflective polarizing film which polarizes and reflects light and paired diffusion films (diffusion base materials) which interposes the reflective polarizing film from front and back. The reflective polarizing film of the reflective polarizing sheet 27 has a multilayer structure, for example, with layers having different refractive indexes alternately laminated, and is configured to transmit a p wave included in light and reflect an s wave to the back side. The s wave reflected by the reflective polarizing film is again reflected by a reflection sheet 20, which will be described further below, or the like to the front side and, at that time, separation is made into the s wave and the p wave. In this manner, as including the reflective polarizing film, the reflective polarizing sheet 27 can reuse the s wave, which is originally supposed to be absorbed by the polarizing plate of the liquid crystal panel 11, by reflecting the s wave to the back side (reflection sheet 20 side), and can enhance light use efficiency (and, in turn, luminance). The paired diffusion films of the reflective polarizing sheet 27 each have a plate surface opposite to a reflective polarizing film side embossed, thereby providing a diffusion action to light. The paired diffusion films are made of synthetic resin, for example, PC (polycarbonate), and have a coefficient of linear expansion of approximately 6×10−5/° C., which is larger than that of the microlens sheet 28, which will be described next. The paired diffusion film each have a thickness of 100 μm or more, which is larger compared with a reflective polarizing film having a thickness on the order of several tens of μm. Therefore, the paired diffusion films are dominant in weight and thickness in the reflective polarizing sheet 27, and also dominant in mechanical properties and thermal properties. The reflective polarizing sheet 27 has an entire thickness on the order of a range from 300 μm to 400 μm, which is thicker than that of the microlens sheet 28, which will be described next. In this manner, the reflective polarizing sheet 27 has a relatively large coefficient of linear expansion compared with the microlens sheet 28, which will be described next, and can be said as a “large-coefficient-of-linear-expansion optical sheet (large-coefficient-of-linear-expansion sheet member)”. The reflective polarizing sheet 27 is formed so that its short-side dimension (dimension in the first direction) and long-side dimension (dimension in the second direction) are smaller than the each dimension of the microlens sheet 28, and is therefore designed so that the outer shape of the reflective polarizing sheet 27 becomes equivalent to the outer shape of the microlens sheet 28 when thermally expanding at the maximum assumed. Also, compared with the microlens sheet 28, which will be described next, the reflective polarizing sheet 27 is relatively heavy and relatively thick, and can be therefore said as a “heavy optical sheet (heavy sheet member)” and a “thick optical sheet (thick sheet member) of a thick type.
Although detailed depiction is omitted, the microlens sheet 28 has a base material and a microlens part provided on a plate surface on a front side of the base material. Of these, the microlens part is configured of unit microlenses arranged in a planar manner, with many aligned in a matrix shape (array shape) along the X axis direction and the Y axis direction. The unit microlenses form a substantially circular shape in a planar view, and are formed as a convex lens forming a substantially semi-spherical shape as a whole. With the structure as described above, the microlens sheet 28 isotropically provides light with a light gathering action (isotropic light gathering action) in the X axis direction and the Y axis direction. The base material of the microlens sheet 28 is made of synthetic resin, for example, PET (polyethylene terephthalate), and its coefficient of linear expansion is approximately 2 to 3×10−5/° C., which is smaller than that of the reflective polarizing sheet 27 described above. As for the base material, its thickness is assumed to be on the order of a range from 100 μm to 300 μm, preferably on the order of 200 μm. As for the microlens part, its thickness is assumed to be on the order of a range from 30 μm to 40 μm. Therefore, the base material is dominant in weight and thickness in the microlens sheet 28, and also dominant in mechanical properties and thermal properties. The microlens sheet 28 has an entire thickness on the order of a range from 130 μm to 340 μm, preferably on the order of 250 μm, which is thinner than that of the reflective polarizing sheet 27. In this manner, the microlens sheet 28 has a relatively small coefficient of linear expansion compared with the above-described reflective polarizing sheet 27, and can thus be said as a “small-coefficient-of-linear-expansion optical sheet (small-coefficient-of-linear-expansion sheet member)”. The microlens sheet 28 is formed so that its short-side dimension (dimension in the first direction) and long-side dimension (dimension in the second direction) are larger than each dimension of the reflective polarizing sheet 27, and is therefore designed so that the outer shape of the microlens sheet 28 becomes equivalent to the outer shape of the reflective polarizing sheet 27 when thermally expanding at the maximum assumed. Compared with the reflective polarizing sheet 27 described above, the microlens sheet 28 has a relatively light weight and is relatively thin, and can be therefore said as a “light-weight optical sheet (light-weight sheet member)” and a “thin optical sheet (thin sheet member) of a thin type. Since this microlens sheet 28 is a “thin sheet member”, compared with the reflective polarizing sheet 27 as a “thick sheet member”, deformation such as a warp or wrinkle intrinsically tends to occur. However, the microlens sheet 28 is disposed so as to be stacked on the back side of the reflective polarizing sheet 27, that is, a side opposite to the output light side. Therefore, even in the event that deformation such as a warp or wrinkle occurs in the microlens sheet 28, that deformation is less visually recognized from a user of the backlight device 12.
The frame 16 has the laterally-elongated frame-shaped part (picture-frame-shaped part, frame-shaped support part) 16a extending along the outer edge of the light guiding plate 19 and the optical sheet 15 as depicted in
The LEDs 17 are of a so-called top-emitting type in which they are surfaced-mounted on the LED substrate 18 and its light-emitting surface 17a is oriented toward a side opposite to an LED substrate 18 side, as depicted in
The LED substrate 18 forms a narrowly-elongated plate shape extending along the long side direction (X axis direction) of the chassis 14 and, is disposed in the chassis 14 so that a mount surface 18a where the LEDs 17 are mounted is opposed to an end face of the light guiding plate 19, as depicted in
The light guiding plate 19 is made of a synthetic resin material which is approximately transparent and has an index of refraction sufficiently higher than that of air (for example, such as acrylic resin such as PMMA or polycarbonate). As depicted in
In the optical sheet 15 and the light guiding plate 19 as optical members which provide optical action to transmitted light in the backlight device 12 according to the present embodiment, as depicted in
The reflective sheet 20 has its plate surface parallel to the plate surface of the light guiding plate 19 and so forth and is disposed so as to cover the output-light opposite plate surface 19c of the light guiding plate 19, as depicted in
The backlight device 12 according to the present embodiment has a sheet support structure (sheet suspension structure) of supporting (suspending) the optical sheet 15 in the vertical direction (Y axis direction, first direction) while allowing thermal expansion or thermal contraction of the optical sheet 15, as depicted in
The first sheet support structure includes paired first sheet support parts 21A which support an upper end side of the reflective polarizing sheet 27 in the vertical direction and paired first supported parts 22A provided to an upper end of the reflective polarizing sheet 27 in the vertical direction, having first openings 23A which the first sheet support parts 21A pass through, and supported by the first sheet support parts 21A passing through the first openings 23A, as depicted in
The sheet support parts 21 is described in detail. The first sheet support parts 21A and the second sheet support parts 21B are provided so as to be integrated with the frame 16, as depicted in
The supported parts 22 is described in detail. As depicted in
The first supported parts 22A and the second supported parts 22B each have formed therein a first opening 23A and a second opening 23B, respectively, forming a hole shape penetrating along its thickness direction (Z axis direction), as depicted in
As described above, since the reflective polarizing sheet 27 and the microlens sheet 28 depicted in
For manufacture, the reflective polarizing sheet 27 and the microlens sheet 28 are each formed into a desired shape by, for example, punching a large sheet parent material along its thickness direction with a blade. Of the reflective polarizing sheet 27 and the microlens sheet 28, at a location where the blade makes contact in the above-described punching, a protrusion such as a burr protruding along the thickness direction (punching direction) may be formed with the above-described punching. In particular, a protrusion such as a burr tends to occur at a location where the outer shape processed by a blade is complex and small. Of the reflective polarizing sheet 27 and the microlens sheet 28, the first supported parts 22A and the second supported parts 22 have relatively complex shapes, and therefore a protrusion such as a burr tends to occur. Among others, the opening edges of the first openings 23A and the second openings 23B are complex and small, and therefore a protrusion such as a burr tends to occur more. Here, if a structure is taken in which the first supported parts and the second supported parts are disposed so as to be superposed in a planar view and supported by common support parts, a protrusion such as a burr occurring at the opening edge of any first opening or the opening edge of any second opening may be caught on the counterpart. If so, the first supported part and the second supported part may stick to each other to inhibit relative displacement at the time of thermal expansion, and there is a possibility of occurrence of deformation such as a wrinkle in the reflective polarizing sheet or the microlens sheet. This deformation that can occur in the reflective polarizing sheet or the microlens sheet tends to become worse as the relative displacement amounts of the first supported parts and the second supported parts at the time of thermal expansion are increased.
In this respect, the second supported parts 22B according to the present embodiment are disposed at positions not superposed on at least the first openings 23A in a planar view, and the first supported parts 22A are disposed at positions not superposed on at least the second openings 23B in a planar view, as depicted in
Furthermore, the second supported parts 22B is positionally displaced with respect to the first supported parts 22A in the horizontal direction, and are arranged so as not to be superposed in a planar view, as depicted in
The above-described sheet support structure is disposed close to ends with respect to the center position of the optical sheet 15 in the horizontal direction, as depicted in
The center-side supported part 25 forms a protrusion piece shape protruding partially upward, that is, to the same orientation as each supported part 22, from an upper edge of the outer edge of the optical sheet 15 in the vertical direction, as depicted in
The center-side supported part 25 has the center-side opening 26 which the center-side sheet support part 24 passes through formed in a hole shape penetrating through the center-side supported part 25 along its thickness direction, as depicted in
The present embodiment has the structure as described above, and its operation is described next. When the above-structured liquid crystal display device 10 is powered ON, driving of the liquid crystal panel 11 is controlled by a control circuit not depicted, and driving power from an LED driving circuit not depicted is supplied to each LED 17 of the LED substrate 18, thereby controlling the driving. As depicted in
When each LED 17 is lit up with the use of the liquid crystal display device 10, each LED 17 generates heat, and various substrates disposed on the back side of the backlight device 12 also generate heat. Other than that, the external environment temperature (room temperature in the case of indoor use, outdoor temperature in the case of outdoor use) may be increased. When the temperature environment is increased, the components of the liquid crystal display device 10 may thermally expand. In particular, the extension amount of the optical sheet 15, which are large and thin optical members, with thermal expansion tends to increase, deformation such as a wrinkle or warp with expansion tends to occur, and optical performance tends to deteriorate. Due to these circumstances, the present embodiment adopts, for example, a sheet support structure which supports the optical sheet 15 in the vertical direction while allowing thermal expansion of the optical sheet 15, and its operation is described below in detail.
First, the temperature environment of the backlight device 12 fluctuates in accordance with the external environment temperature and the use situation of the liquid crystal display device 10. While a lowest temperature environment is such that a state is assumed in which the backlight device 12 is not lit up at a low external environment temperature, a highest temperature environment is such that a state is assumed in which the backlight device 12 is lit up with maximum luminance at a high external environment temperature.
For example, when the use of the liquid crystal display device 10 is started in the lowest temperature environment depicted in
In detail, since the coefficient of linear expansion of the reflective polarizing sheet 27 is larger than that of the microlens sheet 28 and the arrangement of the first supported parts 22A in the horizontal direction is closer to the ends than the second supported parts 22B as depicted in
The first supported parts 22A and the second supported parts 22B which are relatively displaced in the horizontal direction in this manner are arranged so as not to be superposed each other in a planar view as depicted in
As the external environment temperature increases and the backlight device 12 is lit up with the maximum luminance, the environment becomes the highest temperature environment. When the environment reaches the highest temperature environment, as depicted in
As described above, the backlight device (lighting device) 12 of the present embodiment includes: the reflective polarizing sheet (first sheet member) 27 having a surface parallel to a first direction and a second direction orthogonal to each other; the first sheet support part 21A which supports one end side of the reflective polarizing sheet 27 in the first direction; the first supported part 22A provided on the one end side of the reflective polarizing sheet 27 and close to an end with respect to a center position in the second direction, having the first opening 23A which the first sheet support part 21A passes through, and supported by the first sheet support part 21A; the microlens sheet (second sheet member) 28 having a surface parallel to the surface of the reflective polarizing sheet 27, stacked on the reflective polarizing sheet 27, and having a coefficient of linear expansion different from a coefficient of linear expansion of the reflective polarizing sheet 27; the second sheet support part 21B which supports the one end side of the microlens sheet 28; and the second supported part 22B provided on the one end side of the microlens sheet 28 and close to the end with respect to the center position in the second direction and supported by the second sheet support part 21B, the second supported part 22B disposed at a position not superposed on at least the first opening 23A.
With this, the reflective polarizing sheet 27 is supported in the first direction, with the first supported part 22A provided on the one end side in the first direction and close to the end with respect to the center position in the second direction being supported by the first sheet support part 21A which passes through the first opening 23A. The microlens sheet 28 stacked on the reflective polarizing sheet 27 is supported in the first direction, with the second supported part 22B provided on the one end side in the first direction and close to the end with respect to the center position in the second direction being supported by the second sheet support part 21B. The reflective polarizing sheet 27 and the microlens sheet 28 thermally expand in the first direction and the second direction as the temperature environment becomes at high temperatures. In the following, operation regarding the second direction is described in detail. When the reflective polarizing sheet 27 and the microlens sheet 28 thermally expand in the second direction, each of the supported parts 22A and 22B is relatively displaced in the second direction accordingly with respect to the reflective polarizing sheet 27 and the microlens sheet 28. As described above, since the reflective polarizing sheet 27 and the microlens sheet 28 have different coefficients of thermal expansion, the displacement amount of the first supported parts 22A and that of the second supported parts 22B in the second direction with thermal expansion are different from each other.
At least the first supported part 22A has the first opening 23A, and there is a possibility that a protrusion such as a burr is formed on its opening edge due to a reason in manufacture. If this protrusion is caught on any second supported part 22B, the first supported part 22A and the second supported part 22B may stick to each other, and relative displacement may be inhibited. By contrast, since the second supported part 22B is disposed at a position not superposed on at least the first opening 23A, even if a protrusion such as a burr is formed on the opening edge of any first opening 23A, the situation hardly occurs in which that protrusion is caught on the second supported part 22B. With this, the first supported part 22A and the second supported part 22B hardly stick to each other. Therefore, even if the displacement amount of the first supported parts 22A in the second direction with thermal expansion is different from that of the second supported parts 22B, relative displacement of the first supported parts 22A and the second supported parts 22B is allowed. Thus, deformation such as a wrinkle hardly occurs in the reflective polarizing sheet 27 and the microlens sheet 28.
The second supported part 22B has the second opening 23B which the second sheet support part 21B passes through. With this, the microlens sheet 28 is supported in the first direction, with the second supported part 22B being supported by the second sheet support part 21B which passes through the second opening 23B. There is a possibility that, in addition to the first opening 23A of the first supported part 22A, the second opening 23B of the second supported part 22B may have a protrusion such as burr formed due to a reason in manufacture. However, the second opening 23B is formed in the second supported part 22B so as not to be superposed on the first opening 23A, and both of the openings 23A and 23B are arranged so as not to be superposed each other. Therefore, when the protrusion is formed on the opening edge of any first opening 23A, the situation hardly occurs in which that protrusion is caught on the opening edge of the second opening 23B. Conversely, when the protrusion is formed on the opening edge of the second opening 23B, the situation hardly occurs in which that protrusion is caught on the opening edge of the first opening 23A. With this, the first supported part 22A and the second supported part 22B hardly stick to each other, and the reflective polarizing sheet 27 and the microlens sheet 28 are made further less deformable.
The second supported part 22B has the second opening 23B disposed at a position not superposed on the first supported part 22A. With this, when a protrusion such as a burr occurs on the opening edge of any second opening 23B, the situation hardly occurs in which that protrusion is caught on the first supported part 22A. With this, the first supported part 22A and the second supported part 22B are prevented from sticking to each other, and the reflective polarizing sheet 27 and the microlens sheet 28 are made still further less deformable.
The second supported part 22B is disposed at a position not superposed on the first supported part 22A. With this, even if a protrusion such as a burr is formed on the outer edge of each supported part 22A, 22B due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the outer edge of each supported part 22A, 22B or the opening edge of the first opening 23A. With this, the first supported part 22A and the second supported part 22B are prevented from sticking to each other, and the reflective polarizing sheet 27 and the microlens sheet 28 are made further less deformable.
The device also includes: the center-side sheet support part 24 which supports a center side in the second direction on the one end side of the reflective polarizing sheet 27 and the microlens sheet 28; the first center-side supported part 25A provided on the one end side of the reflective polarizing sheet 27 and at a center position in the second direction, having the first center-side opening 26A which the center-side sheet support part 24 passes through, and supported by the center-side sheet support part 24; and the second center-side supported part 25B provided on the one end side of the microlens sheet 28 and at the center position in the second direction, superposed on the first center-side opening 26A, having the second center-side opening 26B which the center-side sheet support part 24 passes through, and supported by the center-side sheet support part 24. With this, the first center-side supported part 25A and the second center-side supported part 25B are provided with the first center-side opening 26A and the second center-side opening 26B superposed each other and, with the common center-side sheet support part 24 passing through these first center-side opening 26A and second center-side opening 26B, the reflective polarizing sheet 27 and the microlens sheet 28 are supported on the center side in the second direction. With this, by sharing the center-side sheet support parts 24 in common, the structure is simplified. The first center-side supported part 25A and the second center-side supported part 25B are portions serving as origins when the reflective polarizing sheet 27 and the microlens sheet 28 extend along the second direction at the time of thermal expansion, and therefore hardly make relative displacement with thermal expansion in the second direction with respect to the center-side sheet support part 24, and are thus prevented from causing deformation such as a wrinkle in the reflective polarizing sheet 27 and the microlens sheet 28.
Either one of the reflective polarizing sheet 27 and the microlens sheet 28 serves as a thick sheet member which is relatively thick, and the other serves as a thin sheet member which is relatively thin, and the microlens sheet 28 as a thin sheet member is disposed so as to be stacked on a side of the reflective polarizing sheet 27 as a thick sheet member opposite to the output light side. With this, since the microlens sheet 28 as a thin sheet member is relatively thin compared with the reflective polarizing sheet 27 as a thick sheet member, deformation such as a wrinkle intrinsically tends to occur. Therefore, as described above, with the microlens sheet 28 as a thin sheet member being disposed so as to be stacked on a side of the reflective polarizing sheet 27 as a thick sheet member opposite to the output light side, even in the event that deformation such as a wrinkle occurs in the microlens sheet 28 as a thin sheet member, that deformation is less visually recognized from the user of the backlight device 12.
The reflective polarizing sheet 27 and the microlens sheet 28 serve as a first optical sheet and a second optical sheet, respectively, each of which provides optical action to light, the device includes the frame (framed-shaped member) 16 which forms a frame shape so as to extend along an outer edge of the first optical sheet and the second optical sheet and also delimits the effective output light area EA of the first optical sheet and the second optical sheet, and the first sheet support part 21A and the second sheet support part 21B are provided to the frame 16. With this, the reflective polarizing sheet 27 and the microlens sheet 28 as the first optical sheet and the second optical sheet in which the effective output light area EA is delimited by the frame 16 are supported in the first direction by the first sheet support part 21A and the second sheet support part 21B provided to the frame 16. Therefore, the arrangement of the effective output light area EA in the reflective polarizing sheet 27 and the microlens sheet 28 as the first optical sheet and the second optical sheet becomes appropriate. Since deformation such as a wrinkle hardly occurs in the reflective polarizing sheet 27 and the microlens sheet 28 as the first optical sheet and the second optical sheet, the output light amount from the effective output light area E is made less nonuniform, and the luminance distribution of emitted light is made uniform.
The liquid crystal display device (display device) 10 according to the present embodiment includes the above-described backlight device 12 and the liquid crystal panel 11 which displays an image by using light applied from the backlight device 12. According to the liquid crystal display device 10 structured as described above, the reflective polarizing sheet 27 and the microlens sheet 28 included in the backlight device 12 are made less deformable, and therefore display performance is excellent.
A second embodiment of the present invention is described with
In the first sheet support structure according to the present embodiment, two sets are provided at positions each at a different distance from the center position of a reflecting polarizing sheet 127 in the horizontal direction, as depicted in
The center-side first sheet support parts 21AC are each disposed at a position interposed between the center-side sheet support part 124 and the second sheet support part 121B of the frame 116 in the horizontal direction, as depicted in
As depicted in
In this manner, the reflective polarizing sheet 127 is supported in the vertical direction by two sets of the first sheet support structure at four locations in total, and therefore is a “heavy sheet member” which is relatively heavy compared with the microlens sheet 128, but loads acting on each of the supported parts 22AC, 22AE, and 125A with supporting are appropriately distributed. With this, the situation hardly occurs in which each of the supported parts 22AC, 22AE, and 125A is damaged or the like by the weight of the reflective polarizing sheet 127, and stable support can be achieved.
As described above, according to the present embodiment, either one of the reflective polarizing sheet 127 and the microlens sheet 128 serves as a heavy sheet member which is relatively heavy, and the other serves as a light-weight sheet member which has a relatively light weight. The reflective polarizing sheet 127 as a heavy sheet member has a larger number of installations of the first supported parts 122A than the microlens sheet 128 as a light-weight sheet member. The reflective polarizing sheet 127 as a heavy sheet member is relatively heavy compared with the microlens sheet 128 as a light-weight sheet member, and therefore the loads on the first supported parts 122A as a support location by the first sheet support parts 121A is large. In this regard, the reflective polarizing sheet 127 as a heavy sheet member has the larger number of installations of the first supported parts 122A than the microlens sheet 128 as a light-weight sheet member. Therefore, the loads on the first supported parts 122A are distributed. With this, the situation hardly occurs in which any first supported part 122A is damaged or the like by the weight of the reflective polarizing sheet 127 as a heavy sheet member, and stable support can be achieved.
A third embodiment of the present invention is described with
An optical sheet 215 according to the present embodiment includes, as depicted in
The prism sheet 29 has, although detailed description is omitted, a base material and a prism part provided on a front plate surface of the base material. Of these, the prism part is configured of unit prisms extending along the X axis direction, with many aligned and disposed along the Y axis direction. The unit prisms form a rail shape (linear shape) parallel to the X axis direction in a planar view, and its cross-section shape along the Y axis direction is a substantially isosceles triangle shape. With the structure as described above, the prism sheet 29 selectively provides light with light gathering action (anisotropic light gathering action) in the Y axis direction (direction of alignment of the unit prisms, direction orthogonal to the extending direction of the unit prisms). The base material of the prism sheet 29 is made of synthetic resin, for example, PET, that is, the same material as that of the microlens sheet 228, and its coefficient of linear expansion is approximately 2 to 3×10−5/° C., which is substantially equal to that of the microlens sheet 228 and is smaller than that of the reflective polarizing sheet 227. As for the base material, its thickness is assumed to be on the order of a range from 100 μm to 300 μm, preferably on the order of 200 μm. As for the prism part, its thickness is assumed to be on the order of a range from 30 μm to 40 μm. Therefore, the base material is dominant in weight and thickness in the prism sheet 29, and also dominant in mechanical properties and thermal properties. The prism sheet 29 has an entire thickness on the order of a range from 130 μm to 340 μm, preferably on the order of 250 μm, which is substantially equal to that of the microlens sheet 228 and thinner than that of the reflective polarizing sheet 227. In this manner, the prism sheet 29 has a relatively small coefficient of linear expansion compared with the reflective polarizing sheet 227, and can therefore be said as a “small-coefficient-of-linear-expansion optical sheet (small-coefficient-of-linear-expansion sheet member)”. The prism sheet 29 is formed so that its short-side dimension (dimension in the first direction) and long-side dimension (dimension in the second direction) are substantially equal to each dimension of the microlens sheet 228 and larger than each dimension of the reflective polarizing sheet 27. Compared with the reflective polarizing sheet 227, the prism sheet 29 has a relatively light weight and is relatively thin, and can be therefore said as a “light-weight optical sheet (light-weight sheet member)” and a “thin optical sheet (thin sheet member)” of a thin type. Therefore, the backlight device 212 according to the present embodiment includes two “small-coefficient-of-linear-expansion optical sheets”, “light-weight optical sheets”, or “thin sheet members”. Since this prism sheet 29 is a “thin sheet member”, compared with the reflective polarizing sheet 227 as a “thick sheet member”, deformation such as a warp or wrinkle intrinsically tends to occur. However, the prism sheet 29 is disposed so as to be stacked on the back side, that is, a side of the reflective polarizing sheet 227 opposite to the output light side. Therefore, even in the event that deformation such as a warp or wrinkle occurs in the prism sheet 29, that deformation is less visually recognized from a user of the backlight device 212.
The prism sheet 29 structured as described above is supported by the second sheet support structure described in the above-described first embodiment with respect to the vertical direction. Therefore, as depicted in
The microlens sheet 228 disposed so as to be stacked on the side opposite to the reflective polarizing sheet 227 side with respect to the prism sheet 29 is supported by a third sheet support structure, which will be described next, in the vertical direction. The third sheet support structure includes paired third sheet support parts 21C which support an upper end side of the microlens sheet 228 in the vertical direction and paired third supported parts 22C provided to an upper end of the microlens sheet 228 in the vertical direction and supported by the third sheet support parts 21C, as depicted in
According to this structure, the microlens sheet 228 stacked on the side opposite to the reflective polarizing sheet 227 side with respect to the prism sheet 29 is supported in the vertical direction, with the third supported parts 22C each provided on one end side in the extending direction and close to an end with respect to the center position in the horizontal direction being supported by the third sheet support part 21C. The third supported parts 22C are disposed at positions not superposed on the first supported parts 222A and the second supported parts 222B. Therefore, even if a protrusion such as a burr is formed on the outer edge of any of the supported parts 22C, 222A, and 222B or the opening edge of any of the openings 223A and 223B due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the outer edge of any of the supported parts 22C, 222A, and 222B or the opening edge of any of the openings 223A and 223B. With this, the third supported parts 22C is prevented from sticking to the first supported parts 222A and the second supported parts 222B, and each of the sheets 29, 227, and 228 is made less deformable. Furthermore, the third supported parts included in the microlens sheet 228 as a “small-coefficient-of-linear-expansion sheet member” each form a protrusion piece shape protruding from the outer edge of the microlens sheet 228 along the horizontal direction, and are each supported by the third sheet support part 21C even with non-opening. As being made with non-opening, the size of the third supported part 22C in the horizontal direction is decreased. Since the microlens sheet 228 has a coefficient of linear expansion smaller than that of the reflective polarizing sheet 227, the displacement amount in the horizontal direction with thermal expansion regarding the third supported part 22C is relatively small, compared with the displacement amount regarding the first supported parts 222A. This is suitable for making the backlight device 212 as a narrow picture frame.
In the microlens sheet 228, a portion on an upper end side and a center side in the horizontal direction is supported in the vertical direction by the center-side sheet support part 224, as depicted in
As described above, according to the present embodiment, the device includes: the microlens sheet (third sheet member) 228 having a surface parallel to the surface of the reflective polarizing sheet 227, stacked on a side of the prism sheet (second sheet member) 29 opposite to the reflective polarizing sheet 227 side, and having a coefficient of linear expansion different from at least the coefficient of linear expansion of the reflective polarizing sheet 227; the third sheet support part 21C which supports the one end side of the microlens sheet 228; the third supported part 22C provided on the one end side of the microlens sheet 228 and close to an end with respect to a center position in the second direction and supported by the third sheet support part 21C, the third supported part 22C disposed at a position not superposed on the first supported part 222A and the second supported part 222B. With this, the microlens sheet 228 stacked on the side of the prism sheet 29 opposite to the reflective polarizing sheet 227 side is supported in the first direction, with the third supported parts 22C each provided on one end side in the first direction and close to an end with respect to the center position in the second direction being supported by the third sheet support part 21C. The third supported parts 22C are disposed at positions not superposed on the first supported parts 222A and the second supported parts 222B. Therefore, even if a protrusion such as a burr is formed on the outer edge of each of the supported parts 22C, 222A, and 222B or the opening edge of the first openings 223A due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the outer edge of each of the supported parts 22C, 222A, and 222B or the opening edge of the openings 223A. With this, the third supported parts 22C is prevented from sticking to the first supported parts 222A and the second supported parts 222B, and the reflective polarizing sheet 227, the microlens sheet 228, and the prism sheet 29 are made further less deformable.
At least either one of the prism sheet 29 and the microlens sheet 228 is a small-coefficient-of-linear-expansion sheet member having a coefficient of linear expansion smaller than that of the reflective polarizing sheet 27, and at least either of the second supported parts 222B and the third supported parts 22C included in the prism sheet 29 and the microlens sheet 228 as a small-coefficient-of linear-expansion sheet member each form a non-opening protrusion piece shape protruding from the outer edge of the relevant one of the prism sheet 29 and the microlens sheet 228 as a small-coefficient-of-linear-expansion sheet member along the second direction. With this, at least either of the second supported parts 222B and the third supported parts 22C included in the relevant one of the prism sheet 29 and the microlens sheet 228 as a small-coefficient-of-linear-expansion sheet member each form a protrusion piece shape protruding from the outer edge of the relevant one of the prism sheet 29 and the microlens sheet 228 as a small-coefficient-of-linear-expansion sheet member along the second direction, and is therefore supported by at least either of the second sheet support parts 221B and the third sheet support parts 21C even in the case of non-opening. With at least either of the second supported parts 222B and the third supported parts 22C being made with non-opening, the size in the second direction is decreased. Since the prism sheet 29 and the microlens sheet 228 as a small-coefficient-of-linear-expansion sheet member has a coefficient of linear expansion smaller than that of the reflective polarizing sheet 227, the displacement amount in the second direction with thermal expansion regarding at least either of the second supported parts 222B and the third supported parts 22C is relatively small, compared with the displacement amount regarding the first supported parts 222A. This is suitable for making the backlight device 212 as a narrow picture frame.
A fourth embodiment of the present invention is described with
The first sheet support parts 321A and the first supported parts 322A according to the present embodiment are disposed close to the center in the horizontal direction of the optical sheet 315 than the second sheet support parts 321B and the second supported parts 322B, as depicted in
A fifth embodiment of the present invention is described with
The first supported parts 422A and the second supported parts 422B according to the mount board are disposed so as to be partially superposed each other in a planar view, as depicted in
A sixth embodiment of the present invention is described with
The second sheet support structure and the third sheet support structure according to the present embodiment are provided as two sets at positions each at a difference distance from the center position of a microlens sheet 528 and a prism sheet 529 in the horizontal direction as depicted in
The center-side second sheet support structure has paired center-side second supported parts 22BC provided at positions each closer to an end than the center position of the upper end of the prism sheet 529 in the horizontal direction, as depicted in
The end-side third sheet support structure has paired end-side third supported parts 22CE protruding from both side ends of the microlens sheet 528 on an upper end in the vertical direction along the horizontal direction, as depicted in
As described above, according to the present embodiment, the prism sheet 529 has a coefficient of linear expansion smaller than that of a reflective polarizing sheet 527, and the end-side second supported parts 22BE as the second supported parts 522B each form a non-opening protrusion piece shape protruding from the outer edge of the prism sheet 529 along the second direction. With this, since the end-side second supported parts 22BE as the second supported parts 522B each form a protrusion piece shape protruding from the outer edge of the prism sheet 529 along the second direction, and are each supported by the second sheet support part 521B even with non-opening. As being made with non-opening, the size of the end-side second supported part 22BE as the second supported part 522B in the second direction is decreased. Since the prism sheet 529 has a coefficient of linear expansion smaller than that of the reflective polarizing sheet 527, the displacement amount in the second direction with thermal expansion regarding the end-side second supported part 22BE as the second supported part 522B is relatively small, compared with the displacement amount regarding first supported parts 522A. This is suitable for making a backlight device 512 as a narrow picture frame.
A seventh embodiment of the present invention is described with
The second sheet support structure according to the present embodiment has paired second supported parts 622B protruding from both side ends of a prism sheet 629 on an upper end in the vertical direction along the horizontal direction, as depicted in
The third sheet support structure has paired third supported parts 622C provided at positions each closer to an end than the center position of the upper end of a microlens sheet 628 in the horizontal direction, as depicted in
As described above, according to the present embodiment, the device includes the microlens sheet 628 having a surface parallel to the surface of the reflecting polarizing sheet 627, stacked on a side of the prism sheet 629 opposite to the side of the reflecting polarizing sheet 627, and having a coefficient of linear expansion different from at least the coefficient of linear expansion of the reflecting polarizing sheet 627; and the third supported part 622C provided on the one end side of the microlens sheet 628 and at a position superposed on the first supported part 622A, the third supported part 622C having the third opening 623C superposed on the first opening 623A, the third opening 623C which a center-side first sheet support part 621AC as a first sheet support part 621A passes through, and supported by the center-side first sheet support part 621AC as the first sheet support part 621A. With this, the microlens sheet 628 stacked on the side of the prism sheet 629 opposite to the reflective polarizing sheet 627 side is supported in the first direction, with the third supported part 622C provided at the position on one end side in the first direction and superposed on the first supported part 622A being supported by the center-side first sheet support part 621AC as the first sheet support part 621A passing through the third opening 623C superposed on the first opening 623A. Since the first supported part 622A and the third supported part 622C are supported by the center-side first sheet support part 621AC as the common first sheet support part 621A, this is suitable for simplification of the structure. Since the prism sheet 629 is interposed between the reflecting polarizing sheet 627 and the microlens sheet 628, even if a protrusion such as a burr is formed on the opening edge of any first opening 623A or the opening edge of any third opening 623C due to a reason in manufacture, the situation hardly occurs in which that protrusion is caught on the third supported part 622C or the first supported part 622A.
An eighth embodiment of the present invention is described with
The second sheet support structure and the third sheet support structure according to the present embodiment have the center-side second sheet support structure and the center-side third sheet support structure described in the above-described six embodiment removed, and are formed only of the end-side second sheet support structure and the end-side third sheet support structure. In detail, the second sheet support structure according to the present embodiment has paired second supported parts 722B protruding from upper ends of both side ends of a prism sheet 729 in the vertical direction along the horizontal direction, as depicted in
As described above, according to the present embodiment, the device includes the microlens sheet 728 having a surface parallel to the surface of the reflecting polarizing sheet 727, stacked on a side of the prism sheet 729 opposite to the side of the reflecting polarizing sheet 727, and having a coefficient of linear expansion equivalent to the coefficient of linear expansion of the prism sheet 729; and the third supported part 722C provided on the one end side of the microlens sheet 728 and at a position superposed on the second supported part 722B and supported by the second sheet support part 721B. With this, the microlens sheet 728 stacked on the side of the prism sheet 729 opposite to the reflective polarizing sheet 727 side is supported in the first direction, with the third supported part 722C provided at the position on one end side in the first direction and superposed on the second supported part 722B being supported by the second sheet support part 721B. Since the second supported part 722B and the third supported part 722C are supported by the common second sheet support part 721B, this is suitable for simplification of the structure. Since the coefficients of linear expansion of the prism sheet 729 and the microlens sheet 728 are equivalent to each other, relative displacement with thermal expansion hardly occurs between the second supported part 722B and the third supported part 722C. Therefore, even if a catch occurs between the second supported part 722B and the third supported part 722C superposed each other, deformation such as a wrinkle hardly occurs in the prism sheet 729 and the microlens sheet 728.
The present invention is not limited to the embodiments described with the above-description and drawings and, for example, the following embodiments are also included in the technical scope of the present invention.
(1) The arrangement of each sheet support part and each supported part described in each embodiment described above in the horizontal direction can be changed as appropriate. For example, By applying the contents described in the above-described fourth embodiment, the arrangement of each sheet support part and each supported part in the horizontal direction described in each embodiment can be replaced. Also, by applying the contents described in the above-described fifth embodiment, an arrangement can be made in which each supported part described in each embodiment is partially superposed.
(2) In each embodiment described above, the structure is described in which one or two sets of the first sheet support structure, the second sheet support structure, and the third sheet support structure are provided. However, three or more sets of at least one of the first sheet support structure, the second sheet support structure, and the third sheet support structure can be installed.
(3) In the above-described second embodiment, the case is described in which, in the structure where two optical sheets are provided, two sets of the first sheet support structure and one set of the second sheet support structure are provided. However, in a structure where three optical sheets are provided, conversely, it is possible to provide one set of the first sheet support structure and two sets of the second sheet support structure.
(4) In the above-described first, second, fourth, and fifth embodiments, the case is described in which, in the structure where two optical sheets are provided, the microlens sheet is disposed on the back side of the reflective polarizing sheet. However, in place of the microlens sheet, a prism sheet can be used. Also, an optical sheet of a type other than the microlens sheet or prism sheet can also be used (such as a diffusion sheet which provides a diffusion action to light or a wavelength conversion sheet containing a phosphor for light wavelength conversion).
(5) In the above-described third and sixth to eighth embodiments, the case is described in which, in the structure where three optical sheets are provided, two sets of the first sheet support structure are provided. However, in the structure where three optical sheets are provided, it is possible to provide one set of the first sheet support structure.
(6) In the above-described third and sixth to eighth embodiments, the case is described in which, in the structure where three optical sheets are provided, the coefficients of linear expansion of the prism sheet and the microlens sheet are equivalent to each other. However, in the structure where three optical sheets are provided, the coefficients of linear expansion of the prism sheet and the microlens sheet may be set differently. In that case, no-superposing arrangement of the second supported part and the third supported part is suitable for preventing sticking between the second supported part and the third supported part.
(7) In the above-described third and sixth to eighth embodiments, a case is possible in which, in the structure where three optical sheets are provided, the prism sheet is disposed and superposed on the front side of the microlens sheet and the microlens sheet is disposed on the front side of the prism sheet in this lamination order.
(8) In the above-described third and sixth to eighth embodiments, the case is described in which, in the structure where three optical sheets are provided, the microlens sheet and the prism sheet are laminated on the back side of the reflective polarizing sheet. However, an optical sheet of a type other than the microlens sheet or prism sheet can also be used (such as a diffusion sheet which provides a diffusion action to light or a wavelength conversion sheet containing a phosphor for light wavelength conversion).
(9) In the above-described third embodiment, the case is described in which the second supported part has an opening structure and the third supported part has a non-opening structure. However, a structure can be adopted in which the second supported part has a non-opening structure, the third supported part has an opening structure, and the third supported part is supported by the third sheet support part provided separately from the first sheet supported part.
(10) From the structure described in the above-described third embodiment, the prism sheet and the second sheet support structure can be removed. In this case, the microlens sheet serves as a “second optical sheet (second sheet member)” superposed on a back side of the reflective polarizing sheet, and a supported part in a non-opening structure the microlens sheet has serves as a “second supported part”.
(11) Other than the structure depicted in the above-described fourth embodiment, the length dimension of each supported part and the length dimension of each opening can be changed as appropriate.
(12) In the above-described sixth embodiment, the case is described in which the second sheet support structure and the third sheet support structure are configured of the center-side second sheet support structure and the center-side third sheet support structure and the end-side second sheet support structure and the end-side third sheet support structure. However, the end-side second sheet support structure and the end-side third sheet support structure can be omitted.
(13) In the above-described seventh embodiment, the case is described in which the third supported part is superposed on the center-side first supported part in a planar view. However, it is possible to adopt a structure in which the third supported part is superposed on the end-side first supported part in a planar view and is supported by the end-side first sheet support part.
(14) In the above-described eighth embodiment, the case is described in which, of the respective supported parts, the second supported part and the third supported part have a non-opening structure and only the first supported part has an opening structure. However, the first supported part and the third supported part may have a non-opening structure and only the second supported part may have an opening structure. Also, the first supported part and the second supported part may have a non-opening structure and only the third supported part may have an opening structure.
(15) In each embodiment described above, the case is described in which the heaviest reflecting polarizing sheet is arranged on the most front side and the microlens sheet and the prism sheet, which have a relatively light weight, are arranged on the back side of the reflective polarizing sheet. However, the reflecting polarizing sheet can be arranged on the back side of the microlens sheet and the prism sheet.
(16) In each embodiment described above, the case is described in which a reflective polarizing sheet is used as a “heavy optical sheet (heavy sheet member)”. However, an optical sheet (diffusion plate which provides a diffusion action to light) of a type other than the reflective polarizing sheet can be used as “heavy optical sheet”.
(17) In each embodiment described above, the case is described in which the sheet support parts are integrally provided to the frame. However, the sheet support parts can be provided to a member other than the frame (such as a light guiding plate, bezel, or chassis).
(18) In each embodiment described above, the case is described in which two or three optical sheets are used. However, as a matter of course, the number of optical sheets to be used can be four or more.
(19) In each embodiment described above, the case is described in which the outer shape of the optical sheet is a rectangle. However, the outer shape of the optical sheet may be a square, circle, oval, or the like. When the outer shape of the optical sheet is changed, the plane shape of the frame is also changed accordingly.
(20) In each embodiment described above, exemplarily described is the backlight device (liquid crystal display device) in a landscape orientation in which the short side direction of the optical sheet matches the vertical direction and the long side direction thereof matches the horizontal direction. However, as a matter of course, a backlight device (liquid crystal display device) in a portrait orientation in which the long side direction of the optical sheet matches the vertical direction and the short side direction thereof matches the horizontal direction.
(21) In each embodiment described above, one is depicted in which the LED substrate (LED) is arranged so that the end face on the lower long side of the light guiding plate in the vertical direction serves as a input light end face. However, the LED substrate (LED) can be arranged so that the end face on the upper long side of the light guiding plate in the vertical direction serves as a input light end face. Also, the LED substrate (LED) can be arranged so that any of end faces on the paired short sides of the light guiding plate in the horizontal direction serves as an input end face.
(22) In each embodiment described above, a one-side input light type is described in which the LED substrate (LED) is arranged so that only one end face of the four end faces of the light guiding plate serves as an input light end face. However, a both-side input light type can be adopted in which paired LED substrates (LEDs) interpose the light guiding plate in the short-side direction so that the end faces on the paired long sides of the four end faces of the light guiding plate serve as input light end faces. Also, a both-side input light type can be adopted in which paired LED substrates (LEDs) interpose the light guiding plate in the long-side direction so that the end faces on the paired short sides of the four end faces of the light guiding plate serve as input light end faces.
(23) Other than the above-described (22), the LED substrate (LED) can be arranged so that end faces on any three sides of the light guiding plate serve as input light end faces, or the LED substrate (LED) can also be arranged so that all end faces on the four sides of the light guiding plates serve as input light end faces.
(24) In each embodiment described above, one is described in which one LED substrate is arranged on one side of the light guiding plate. However, a plurality of LED substrates may be arranged on one side of the light guiding plate.
(25) In each embodiment described above, the LED of a top-face light emission type is described. However, an LED of a side-face light emission type can be used as a light source. Also, the number of implementation of LEDs on the LED substrate can be changed as appropriate. Also, a light source other than the LED (such as an organic EL) can be used.
(26) In each embodiment described above, a backlight device of an edge-light type is exemplarily described. However, the present invention can be applied also to a backlight device of a downlight type. In this case, the backlight device of the downlight type does not have a light guiding plate included in the backlight device of the edge-light type, and the LED substrate is arranged so that the mount surface of LEDs is in parallel to the plate surface of the bottom surface of the chassis and is opposed, with a space, to the plate surface of the optical sheet arranged on a light emission part in the chassis. The LED substrate is preferably arranged so that LEDs are disposed in a matrix in the surface of the bottom part of the chassis. Also, preferably, the reflective sheet is installed so as to cover the mount surface of the LED substrate and an LED insertion hole which each LED passes through are formed in that reflective sheet. Furthermore, a diffusion lens can also be installed which diffuses light so as to cover the light emission surface of the LEDs.
(27) In each embodiment described above, a TFT is used as a switching element of the liquid crystal display device. However, the present invention can be applied also to a liquid crystal display device using a switching element other than the TFT (for example, thin film diode (TFD)), and can be applied not only to a liquid crystal display device for color display but also to a liquid crystal display device for monochrome display.
(28) In each embodiment described above, a liquid crystal display device of a transmission type is exemplarily described. Other than that, the present invention can be applied also to a liquid crystal display device of a half-transmission type.
(29) In each embodiment described above, a liquid crystal display device using a liquid crystal panel as a display panel is exemplarily described. However, the present invention can be applied also to a display device using a display panel of another type (for example, such as MEMS (Micro Electro Mechanical Systems) display panel).
(30) In each embodiment described above, a television receiving device including a tuner is exemplarily described. However, the present invention can be applied also to one not including a tuner. Specifically, the present invention can be applied also to a liquid crystal display device to be used as an electronic signage (digital signage) or electronic blackboard. Also, a specific screen size of the liquid crystal panel can be changed as appropriate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-172735 | Sep 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/030864 | 8/29/2017 | WO | 00 |
