WO2012023459A1

WO2012023459A1 - Illuminating device, display device and television receiver

Info

Publication number: WO2012023459A1
Application number: PCT/JP2011/068147
Authority: WO
Inventors: 香織生田
Original assignee: シャープ株式会社
Priority date: 2010-08-20
Filing date: 2011-08-09
Publication date: 2012-02-23

Abstract

The purpose of the present invention is to eliminate or suppress luminance non-uniformity of the display surface without increasing the number of light sources in an illuminating device. A backlight device of the present invention is provided with: an LED light source (28), which has light distribution wherein light having a peak emission intensity travels in the tilted direction with respect to the front direction; a chassis (22) which houses the LED light source (28), and which is opened to the light outputting side; a reflection member (26), which has a plurality of tilted surfaces (26a) that are tilted from the surface where the LED light source (28) is disposed to the side where the chassis (22) is opened, and which directs the light emitted from the LED light source (28) to the front direction of the LED light source (28) by means of the tilted surface (26a); and a diffuser panel (20), which is provided on the side where the chassis (22) is opened, and has a light blocking pattern (25) printed on the surface that faces the LED light source (28).

Description

Lighting device, display device, and television receiver

The present invention relates to a lighting device, a display device, and a television receiver.

In recent years, display elements of image display devices such as television receivers are shifting from conventional cathode ray tubes to thin display devices to which thin display elements such as liquid crystal panels and plasma display panels are applied. Is possible. The liquid crystal display device requires a backlight device as a separate illumination device because the liquid crystal panel used for this does not emit light.

As a backlight device, a direct-type backlight device that directly supplies light from the back surface to a liquid crystal panel is known. In such a backlight device, a reflection member may be disposed on an installation surface on which a light source such as an LED is installed.

Patent Document 1 discloses a reflective member that is used in a direct backlight device or the like and has a three-dimensional shape having a plurality of inclined surfaces that are inclined from the LED installation surface toward the liquid crystal panel. . By applying such a reflective member to a direct type backlight device including LEDs as a light source, the light from each LED is directed to the liquid crystal panel side by the inclined surface of the reflective member. Brightness unevenness can be prevented or suppressed.

JP 2008-292991 A

(Problems to be solved by the invention)
However, in the direct type backlight device to which the reflecting member of Patent Document 1 is applied, when the backlight device is thinned, the light emitted from the LED is emitted to the liquid crystal panel side in a state where the light is not sufficiently reflected, and the liquid crystal panel Luminance unevenness may occur on the display surface of the panel. In this case, unless the number of LEDs is increased, luminance unevenness on the display surface of the liquid crystal panel cannot be prevented or suppressed, and there are problems such as an increase in LED mounting cost and an increase in power consumption accompanying the increase in LEDs. .

The technology disclosed in this specification has been created in view of the above problems. The technology disclosed in this specification is a technology that can prevent or suppress uneven brightness on the display surface without increasing the number of light sources in a direct-type illumination device including a reflective member that directs light on the display surface. The purpose is to provide.

(Means for solving problems)
The technology disclosed in this specification includes a light source having a light distribution such that light having a peak emission intensity is directed in a direction inclined with respect to the front direction, and the light source is accommodated and directed toward the light emitting side. And a reflecting member that directs light from the light source in the front direction of the light source by the inclined surface. The reflecting member has a plurality of inclined surfaces that are inclined from the installation surface of the light source toward the opening side of the chassis. And a diffusing plate disposed on the opening side of the chassis and having a light shielding pattern printed on a surface facing the light source.

Since the light-shielding pattern printed on the surface of the diffuser plate facing the light source is a light-shielding pattern for light incident from the front direction, when light enters from an oblique direction, the light may pass through the light-shielding pattern. In this case, luminance unevenness occurs when the display surface is viewed from an oblique direction. According to the illuminating device described above, the light from the light source is directed in the front direction of the light source by the reflecting member, so that the light is incident on the surface facing the light source of the diffusion plate on which the light shielding pattern is printed, from an oblique direction. Can be prevented or suppressed. For this reason, all or most of the light incident on the diffusion plate can be suitably adjusted by the light-shielding pattern printed on the diffusion plate, thereby preventing or suppressing luminance unevenness of the display surface of the light transmitted through the diffusion plate. Can do.

A plurality of the light shielding patterns may be printed on the entire surface of the diffusion plate facing the light source.
According to this configuration, most of the light directed in the front direction of the light source by the reflecting member can be applied to the light shielding pattern of the diffusing plate, so that uneven brightness on the display surface can be further prevented or suppressed.

Each of the plurality of light shielding patterns may have a different degree of light shielding according to the printing density, and the printing density may be adjusted according to the luminance of light incident on the light shielding pattern.
According to this configuration, an effective luminance design of the display surface can be performed by adjusting the printing density of the light shielding pattern.

Each of the plurality of light shielding patterns may have a plurality of portions having different printing densities.
According to this configuration, the print density can be finely adjusted in each light shielding pattern, and more effective luminance design of the display surface can be performed.

Each of the plurality of light shielding patterns may be formed of a plurality of striped or dot-like layers having different printing densities.
According to this configuration, each light shielding pattern can be formed in a predetermined shape, and the light shielding pattern can be efficiently printed on the diffusion plate.

The angle of the inclined surface of the reflecting member with respect to the front direction of the light source is smaller than the angle formed with respect to the front direction of light from the light source that has a peak emission intensity. May be.
According to this configuration, light having a peak emission intensity among the light from the light source hits the inclined surface of the reflecting member, so that most of the light emitted from the light source can be directed in the front direction of the light source. For this reason, it is possible to further prevent or suppress luminance unevenness of the display surface of light transmitted through the diffusion plate on which the light shielding pattern is printed.

The light shielding pattern may be printed on the diffusion plate by any one of gravure printing, ink jet printing, and silk screen printing.
According to this configuration, by using a predetermined printing method, it is possible to efficiently print the light shielding pattern on the diffusion plate.

The reflective member may be shaped to individually surround the light sources.
According to this configuration, since the light from each light source can be effectively directed to the display surface side by the reflecting member, luminance unevenness on the display surface can be further prevented or suppressed.

The reflection member may have a constant inclination angle of the plurality of inclined surfaces.
According to this configuration, the direction in which light is directed can be made constant on each inclined surface, and a uniform luminance distribution can be formed on the light emission side of the light source.

An interval between the adjacent light sources may be constant.
According to this configuration, a uniform luminance distribution can be formed on the light emission side of the light source.

The interval between the adjacent light sources may not be constant, and the inclination angles of the plurality of inclined surfaces of the reflecting member may be adjusted according to the interval between the adjacent light sources.
According to this configuration, even if the interval between the light sources is not constant, a uniform luminance distribution can be formed on the light emission side of the light source. Therefore, the number of light sources can be reduced while preventing or suppressing luminance unevenness on the display surface, and the mounting cost of the light sources, the power consumption of the lighting device, and the like can be reduced.

The technology disclosed in this specification can also be expressed as a display device including a display panel that performs display using light from the above-described lighting device. A display device in which the display panel is a liquid crystal panel using liquid crystal is also new and useful. A television receiver provided with the above display device is also new and useful. According to the display device and the television set described above, the display area can be increased.

(The invention's effect)
According to the technology disclosed in this specification, in a direct illumination device including a reflective member that directs light on a display surface, luminance unevenness on the display surface can be prevented or suppressed without increasing the number of light sources. Technology that can be provided.

1 is an exploded perspective view of a television receiver TV according to Embodiment 1. FIG. An exploded perspective view of the liquid crystal display device 10 is shown. The top view of the backlight apparatus 24 is shown. The top view which looked at the diffusion plate 20 from the back side is shown. A cross-sectional view of the backlight device 24 is shown. The expanded sectional view of the backlight apparatus 24 is shown. In a normal direct type backlight device provided with a reflecting member 26, the luminance distribution on the display surface of the liquid crystal panel when two LED light sources are arranged in parallel in the X-axis direction is shown. In the backlight device 24 according to Embodiment 1, the luminance distribution on the display surface of the liquid crystal panel 16 when two LED light sources 28 are arranged in parallel in the X-axis direction is shown. The top view of the backlight apparatus 124 which concerns on Embodiment 2 is shown. The top view which looked at the diffusion plate 120 from the back side is shown. The top view of the backlight apparatus 224 which concerns on Embodiment 3 is shown. The top view which looked at the diffusion plate 220 from the back side is shown.

<Embodiment 1>
Embodiment 1 will be described with reference to the drawings. A part of each drawing shows an X-axis, a Y-axis, and a Z-axis, and each axis direction is drawn in a common direction in each drawing. Among these, the Y-axis direction coincides with the vertical direction, and the X-axis direction coincides with the horizontal direction.

FIG. 1 is an exploded perspective view of the television receiver TV according to the first embodiment. As shown in FIG. 1, the television receiver TV includes a liquid crystal display device 10, front and back cabinets Ca and Cb that are accommodated so as to sandwich the liquid crystal display device 10, a power source P, a tuner T, and a stand S. I have. The liquid crystal display device 10 has a horizontally long rectangular shape as a whole and is accommodated in a vertically placed state.

FIG. 2 is an exploded perspective view of the liquid crystal display device 10. Here, the upper side shown in FIG. 2 is the front side, and the lower side is the back side. As shown in FIG. 2, the liquid crystal display device 10 includes a liquid crystal panel 16 that is a display panel and a backlight device 24 that is an external light source, and these are integrally held by a bezel 12 or the like having a frame shape. It is like that.

Subsequently, the liquid crystal panel 16 will be described. The liquid crystal panel 16 has a configuration in which a pair of transparent (highly translucent) glass substrates are bonded together with a predetermined gap therebetween, and a liquid crystal layer (not shown) is sealed between the glass substrates. Is done. One glass substrate is provided with a switching element (for example, TFT) connected to a source wiring and a gate wiring orthogonal to each other, a pixel electrode connected to the switching element, an alignment film, and the like. The substrate is provided with a color filter and counter electrodes in which colored portions such as R (red), G (green), and B (blue) are arranged in a predetermined arrangement, and an alignment film. Of these, image data and various control signals necessary for displaying an image are supplied to a source wiring, a gate wiring, a counter electrode, and the like from a drive circuit board (not shown). A polarizing plate (not shown) is disposed outside both glass substrates.

Subsequently, the backlight device 24 will be described. FIG. 3 shows a plan view of the backlight device 24. FIG. 4 is a plan view of the diffusing plate 20 as viewed from the back side, and shows a plan view of the back surface 20 a of the diffusing plate 20. FIG. 5 shows a cross-sectional view of a cross section of the backlight device 24 cut in the horizontal direction (X-axis direction). As shown in FIG. 2, the backlight device 24 includes a chassis 22, a diffusion plate 20, an optical member 18, and a frame 14. The chassis 22 has a substantially box shape opened to the front side (light emitting side, liquid crystal panel 16 side). The diffusion plate 20 is disposed on the front side of the chassis 22 so as to cover the opening of the chassis 22. The optical member 18 is disposed on the front side of the diffusion plate 20. The frame 14 has a frame shape and supports the liquid crystal panel 16 along the inner edge.

In the chassis 22, an LED substrate 30 (see FIG. 5) on which a plurality of light emitting diode (LED) light sources 28 are arranged and a reflecting member 26 are accommodated. Note that the backlight device 24 has a light emitting side on the diffusion plate 20 side rather than the LED substrate 30 side, and is a direct type in which light is directly supplied to the liquid crystal panel 16 from the back side through the diffusion plate 20 and the like. This is a backlight device.

The chassis 22 is made of, for example, a metal such as an aluminum-based material, and includes a bottom plate 22a, a side plate 22c, and a receiving plate 22d. Is made. The bottom plate 22 a has a horizontally long rectangular shape as in the liquid crystal panel 16, and is disposed on the back side of the LED substrate 30, that is, on the side opposite to the light emitting side of the LED light source 28. The side plate 22c rises from the outer edge of each side of the bottom plate 22a. The receiving plate 22d projects outward from the rising end of each side plate 22c, and the diffusion plate 20 and the frame 14 can be placed on the front side. The frame 14 is fixed to the receiving plate 22d by being screwed to the receiving plate 22d. The long side direction of the chassis 22 coincides with the X-axis direction (horizontal direction), and the short side direction thereof coincides with the Y-axis direction (vertical direction).

Subsequently, the LED substrate 30 and the LED light source 28 disposed on the surface of the LED substrate 30 will be described. As shown in FIG. 5, the LED substrate 30 has a horizontally long flat plate shape similar to the bottom plate 22 a of the chassis 22. The long side direction coincides with the X axis direction, and the short side direction coincides with the Y axis direction. In the state, it is laid on the front side of the bottom plate 22 a of the chassis 22. The LED board 30 has a size that can cover the entire area of the bottom plate 22a, specifically, a size that can cover many portions on the center side excluding the outer peripheral end of the bottom plate 22a. Yes.

The LED light source 28 is mounted on the surface 30 a of the LED substrate 30. As shown in FIG. 3, the LED light sources 28 are arranged in parallel on the LED substrate 30 in a plurality of planes in the X-axis direction and the Y-axis direction. The arrangement pitch of the LED light sources 28 arranged in parallel along the X-axis direction and the arrangement pitch of the LED light sources 28 arranged in parallel along the Y-axis direction are fixed. The LED light sources 28 are connected to each other by a wiring pattern (not shown) formed on the LED substrate 30. Driving power is supplied to the LED light source 28 by a power supply circuit board (not shown) attached to the back side of the bottom plate 22 a of the chassis 22.

The LED light source 28 emits white light. For example, three types of LED chips (not shown) of red, green, and blue may be surface-mounted, or the blue light emitting element emits light in a yellow region. It may be one that emits white light by applying a phosphor having a peak. Alternatively, the blue light emitting element may emit white light by applying a phosphor having emission peaks in the green and red regions. Further, a phosphor having a light emission peak in a green region may be applied to a blue light emitting element, and white light may be emitted by combining a red light emitting element. The LED light source 28 may emit white light by combining a blue light emitting element, a green light emitting element, and a red light emitting element. Further, a combination of an ultraviolet light emitting element and a phosphor may be used. In particular, an ultraviolet light-emitting element may emit white light by applying a phosphor having emission peaks in blue, green, and red, respectively.

The reflection member 26 is made of a synthetic resin material having thermoplasticity, and the surface thereof has a white color with excellent light reflectivity. The reflection member 26 is laid on the front side of the LED board 30 laid on the surface of the chassis 22 and has a size that can cover the LED board 30 over almost the entire area. The reflecting member 26 extends along the LED substrate 30 and includes four rising portions 26c and four extending portions 26e as shown in FIGS. The rising portions 26 c rise from the outer peripheral end of the bottom portion of the reflecting member 26 and have a shape that is inclined with respect to the bottom plate 22 a of the chassis 22. The extending portion 26 e extends outward from the outer end of each rising portion 26 c and is placed on the receiving plate 22 d of the chassis 22. In addition, a plurality of light source insertion holes 26d through which the LED light sources 28 are individually inserted are provided on the bottom portion of the reflection member 26 at positions overlapping the LED light sources 28 in plan view. The light source insertion holes 26d are arranged in parallel in the X-axis direction and the Y-axis direction corresponding to the arrangement of the LED light sources 28.

Further, the reflecting member 26 is provided with a plurality of inclined surfaces 26a that are inclined from the LED substrate 30 side to the front side (side where the chassis 22 is opened). The inclination angle of each inclined surface 26a is fixed. The inclined surface 26 a is formed by projecting many portions excluding the hole edge of each light source insertion hole 26 d to the front side, and the remaining portion of the bottom of the reflecting member 26 is supported by the LED substrate 30. . And the inclined surface 26a is made into the circular-arc-shaped curved surface about the circumferential direction, and is formed so that each LED light source 28 may be enclosed individually in an inverted cone shape. And the inclined surface 26a can direct the light emitted from each LED light source 28 and reaching the inclined surface 26a to the front side (the diffuser plate 20 side). The projecting tip portions of each inclined surface 26 a are connected via a top surface portion 26 b parallel to the surface of the LED substrate 30. Further, the inclined surface 26 a is in a state where the tip thereof is not in contact with the diffusion plate 20.

Subsequently, the diffusion plate 20 and the optical member 18 arranged on the opening side of the chassis 22 will be described. The diffusion plate 20 is placed on the receiving plate 22d of the chassis via the extending portion 26e of the reflecting member 26 so as to be parallel to the LED substrate 30, and covers the opening side of the chassis 22. The diffusing plate 20 has a structure in which a large number of diffusing particles are dispersed in a substantially transparent resin base material having a predetermined thickness, and has a function of diffusing transmitted light. As shown in FIG. 4, a plurality of the same light shielding patterns 25 are printed on the back surface (surface facing the LED light source 28) 20 a of the diffusion plate 20 by gravure printing over the entire surface.

The printing density of each light shielding pattern 25 is adjusted according to the luminance of incident light. Specifically, each light-shielding pattern 25 is a striped pattern composed of

quadruple circles

25a, 25b, 25c, and 25d, and the print density gradually increases from the innermost circle 25a toward the outermost circle 25d. It is getting thinner. The light shielding pattern 25 is a pattern in which a plurality of minute reflective dots having a reflectance of almost 100% are printed. The density of the reflective dots is high in a portion where the print density is high, and the density of the reflective dots is low in a portion where the print density is low. ing. Accordingly, a portion with a high printing density has a high reflectance (low transmittance), and a portion with a low printing density has a low reflectance (high transmittance).

A part of the light incident from the front direction with respect to the back surface 20a of the diffusion plate 20 is reflected according to the print density of the incident light shielding pattern 25, and the rest is transmitted through the diffusion plate 20 and emitted to the liquid crystal panel 16 side. Will be. The reflected light is reflected by the reflecting member 26, is incident on the back surface of the diffusion plate 20 again, and is repeatedly reflected until it passes through the diffusion plate 20. In this way, light corresponding to the light shielding pattern 25 is emitted from the surface of the diffusion plate 20. In addition, when light having a high emission intensity and light having a low emission intensity are incident on a light shielding pattern having the same print density, light having a higher light emission intensity transmits more light through the light shielding pattern. . In the backlight device 24, the light shielding pattern 25 has a positional relationship in which light with high emission intensity is incident on a portion with high reflectance and light with low emission intensity is incident on a portion with low reflectance. The LED light source 28, the inclined surface 26a of the reflecting member 26, and the light shielding pattern 25 are arranged. For this reason, the luminance distribution of the light transmitted through the diffusion plate 20 and displayed on the light exit surface of the diffusion plate 20 is made substantially uniform.

The optical member 18 covers almost the entire surface of the diffusion plate 20 and is arranged on the front side of the diffusion plate 20. A liquid crystal panel 16 is installed on the front side of the optical member 18, and the optical member 18 is disposed between the diffusion plate 20 and the liquid crystal panel 16. The optical member 18 is configured by laminating two sheets. The optical member 18 imparts a predetermined optical action to the light emitted from the LED light source 28 and transmitted through the diffusion plate 20, and the light is transmitted to the outside on the front side. It can be emitted. Examples of these two sheets include a diffusion sheet, a lens sheet, a reflective polarizing sheet, and the like, which can be appropriately selected and used.

Subsequently, the light distribution of the LED light source 28 will be described. FIG. 6 is a cross-sectional view of the backlight device 24 and shows a cross-sectional view in which a part of FIG. 5 is enlarged. In FIG. 6, reference symbol L indicates an emission direction of light having a peak emission intensity among the light emitted from the LED light source 28. As shown in FIG. 6, each LED light source 28 is mounted on the surface of the LED substrate 30, and is configured by a substrate portion 28a that emits light and a transparent hemispherical light emitting surface 28b that covers the substrate portion 28a. Yes. The LED light source 28 has a light distribution such that light having a peak emission intensity is directed in a direction inclined with respect to the front direction of the LED light source 28. Here, the specific unit of emission intensity can be radiant intensity (W / sr · m2), radiant flux (W), irradiance (W / m2), etc. It is also possible to do.

The light with the peak emission intensity is emitted radially from the center of the LED light source 28 and travels in a direction L that forms a predetermined angle A with respect to the front direction of the LED light source 28. Thereby, the light emitted from the LED light source 28 is diffused over a wide range. On the other hand, the inclined surface 26 a of the reflecting member 26 forms a predetermined angle B with respect to the front direction of the LED light source 28. In the backlight device 24, the relationship of angle A> angle B is established. For this reason, of the light emitted from the LED light source 28, the light having the peak emission intensity hits the inclined surface 26 a of the reflecting member 26, and most of the light emitted from the LED light source 28 is directed in the front direction of the LED light source 28. Oriented.

Of the light emitted from the LED light source 28, the light emitted in the front direction of the LED light source 28 is directly incident on the back surface of the diffusion plate 20 from the front direction without being reflected by the reflecting member 26. . On the other hand, the intensity of the light directed in the front direction of the LED light source 28 by the reflecting member 26 decreases. Therefore, the light having the highest intensity among the light incident on the light shielding pattern 25 is light incident on a portion located immediately above the LED light source 28. For this reason, the relative position of the light shielding pattern 25 and the LED light source 28 is adjusted so that the darkest portion (25a) of the light shielding pattern 25 is located in the front direction of the LED light source 28.

Subsequently, the operation of the backlight device 24 according to the present embodiment will be described. When each LED light source 28 of the backlight device 24 is turned on, most of the light emitted from each LED light source 28 in a wide range directly or against the light shielding pattern 25 printed on the back surface 20a of the diffusion plate 20 Directed by the inclined surface 26a of the reflecting member 26 and indirectly incident from the front direction. The light that passes through the diffusion plate 20 is diffused by the diffusion plate 20, is emitted from the front side, and enters the optical member 18. The light transmitted through the optical member 18 is emitted toward the liquid crystal panel 16.

Here, a description will be given of the contrast between the luminance distribution of the display surface in a normal direct backlight device including the reflecting member 26 and the luminance distribution of the display surface in the backlight device 24 according to the present embodiment. FIG. 7 shows a normal direct-type backlight device having a reflecting member 26 (in other words, in the backlight device 24 according to this embodiment, the LED light source 28 and the diffusion plate 20 on which the light shielding pattern 25 is printed are applied. In the case of not), the luminance distribution of the display surface of the liquid crystal panel when two LED light sources are arranged in parallel in the X-axis direction is shown. On the other hand, FIG. 8 shows the luminance distribution on the display surface of the liquid crystal panel 16 when the two LED light sources 28 are arranged in parallel in the X-axis direction in the backlight device 24 according to the present embodiment. 7 and 8, the vertical axis indicates the light emission intensity (arbitrary unit), and the horizontal axis indicates the LED light source arrangement (arbitrary unit) in the X-axis direction.

As shown in FIG. 7, when the diffuser plate 20 on which the LED light source 28 and the light shielding pattern 25 according to the present embodiment are not applied, the liquid crystal panel is in a state where the light emitted from the LED light source is not sufficiently multiply reflected. Therefore, the emission intensity peaks are formed at positions corresponding to the positions of the two LED light sources. On the other hand, in the backlight device 24 according to the present embodiment, as shown in FIG. 8, the peak of the light emission intensity is substantially uniform along the X-axis direction. This is because light emitted from the LED light source 28 is diffused over a wide range, so that most of the light is directed toward the front surface of the LED light source 28 by the reflecting member 26, and thereby the light transmitted through the light shielding pattern 25. Is suitably adjusted according to the printing density, and the luminance distribution is almost uniform on the light exit surface of the diffusion plate 20. Such a luminance distribution is realized when most of the light incident on the light shielding pattern 25 printed on the diffusion plate 20 enters from the front direction. That is, the diffusion plate 20 on which the light shielding pattern 25 is printed by combining the diffusion plate 20 on which the light shielding pattern 25 is printed and the reflecting member 26 that directs light in the front direction with respect to the surface on which the light shielding pattern 25 is printed. 20 effects can be suitably obtained.

When the LED light source 28 having a high diffusion light distribution is not applied among the LED light source 28 having a high diffusion light distribution, the reflecting member 26, and the diffusion plate 20 having the light shielding pattern 25 printed on the surface facing the LED light source 28, The light emitted from the LED light source 28 cannot be sufficiently applied to the reflecting member 26, and light incident from the oblique direction to the back surface 20 a of the diffusion plate 20 on which the light shielding pattern 25 is printed is generated. Even when the reflecting member 26 is not applied, the light emitted from the LED light source 28 is not directed, so that light incident on the rear surface 20a of the diffusion plate 20 from an oblique direction is generated. In these cases, luminance unevenness occurs when the display surface of the liquid crystal panel 16 is viewed from an oblique direction. In addition, when the diffusion plate 20 on which the light shielding pattern 25 is not printed is applied, the light emitted from the LED light source 28 is emitted to the liquid crystal panel side in a state where it is not sufficiently multiple-reflected. Brightness unevenness occurs. On the other hand, the backlight device 24 according to the present embodiment includes an LED light source 28 having a high diffusion light distribution, a reflecting member 26 that directs light in the front direction of the surface on which the light shielding pattern 25 is printed, By providing the diffusing plate 20 on which the light shielding pattern 25 is printed, luminance unevenness of the liquid crystal panel 16 is prevented or suppressed.

As described above, in the backlight device 24 according to the present embodiment, the back surface of the diffusion plate 20 on which the light shielding pattern 25 is printed by directing the light from the LED light source 28 toward the front of the LED light source 28 by the reflecting member 26. It is possible to prevent or suppress light from entering obliquely from 20a. For this reason, all or most of the light incident on the diffusing plate 20 can be suitably adjusted by the light shielding pattern 25 printed on the diffusing plate 20, thereby preventing or suppressing luminance unevenness on the display surface of the liquid crystal panel 16. Can do.

In addition, in the direct type backlight device including the reflecting member 26, when the LED light source 28 having a high diffusion light distribution and the diffusion plate 20 on which the light shielding pattern 25 is printed are not applied, the LED light source is reduced when the backlight device is thinned. Unless the number is increased, luminance unevenness on the display surface cannot be prevented or suppressed. In the backlight device 24 according to the present embodiment, since the luminance unevenness of the display surface can be prevented or suppressed without increasing the number of LED light sources, the mounting cost of the LED light sources is reduced as compared with the case where the number of LED light sources is increased. In addition, power consumption by the LED light source can be reduced.

In the backlight device 24 according to the present embodiment, a plurality of light shielding patterns 25 are printed on the entire back surface 20a of the diffusion plate 20. For this reason, most of the light directed in the front direction of the LED light source 28 by the reflecting member 26 can be applied to the light shielding pattern 25 of the diffusing plate 20, thereby further preventing or suppressing luminance unevenness on the display surface of the liquid crystal panel 16. Can do.

Further, in the backlight device 24 according to the present embodiment, each of the plurality of light shielding patterns 25 has a different degree of light shielding according to the print density, and the light shielding pattern 25 has a light shielding degree according to the luminance of light incident on the light shielding pattern 25. The print density is adjusted. For this reason, by adjusting the printing density of the light shielding pattern 25, it is possible to perform effective luminance design of the display surface of the liquid crystal panel 16.

Further, in the backlight device 24 according to the present embodiment, each of the plurality of light shielding patterns 25 has a plurality of portions having different printing densities. For this reason, the print density can be finely adjusted in each light shielding pattern 25, and more effective luminance design of the display surface of the liquid crystal panel 16 can be performed.

Further, in the backlight device 24 according to the present embodiment, each of the plurality of light shielding patterns 25 includes a plurality of striped layers having different printing densities. For this reason, each light shielding pattern 25 can be formed in a predetermined shape, and the light shielding pattern 25 can be efficiently printed on the diffusion plate 20.

Further, in the backlight device 24 according to this embodiment, the angle B formed with respect to the front direction of the LED light source 28 on the inclined surface 26 a of the reflecting member 26 has a peak emission intensity in the light from the LED light source 28. The angle is smaller than the angle A formed by the light with respect to the front direction. As a result, the light having the peak emission intensity among the light from the LED light source 28 strikes the inclined surface 26 a of the reflecting member 26, so that most of the light emitted from the LED light source 28 is directed in the front direction of the LED light source 28. Can be oriented. As a result, luminance unevenness on the display surface of the liquid crystal panel 16 can be further prevented or suppressed.

Further, in the backlight device 24 according to the present embodiment, the light shielding pattern 25 is printed on the diffusion plate 20 by gravure printing. For this reason, the light shielding pattern 25 can be efficiently printed on the diffusion plate 20.

Further, in the backlight device 24 according to the present embodiment, the reflecting member 26 is shaped so as to individually surround the LED light sources 28. For this reason, the light from each LED light source 28 can be effectively directed to the display surface side of the liquid crystal panel 16 by the reflecting member 26, and luminance unevenness on the display surface of the liquid crystal panel 16 can be further prevented or suppressed. it can.

Further, in the backlight device 24 according to the present embodiment, the reflecting member 26 has a constant inclination angle of the plurality of inclined surfaces 26a. For this reason, the direction in which light is directed can be made constant on each inclined surface 26a, and a uniform luminance distribution can be formed on the light emitting side of the LED light source 28.

Further, in the backlight device 24 according to the present embodiment, the interval between the adjacent LED light sources 28 is constant. For this reason, a uniform luminance distribution can be formed on the light emitting side of the LED light source 28.

<Embodiment 2>
A second embodiment will be described with reference to the drawings. FIG. 9 is a plan view of the backlight device 124 according to the second embodiment. FIG. 10 is a plan view of the diffusing plate 120 viewed from the back side, and shows a plan view of the back surface 120a of the diffusing plate 120. FIG. In the second embodiment, the shape of the reflection member 126 and the light shielding pattern 125 printed on the diffusion plate 120 are different from those in the first embodiment. Since the other configuration is the same as that of the first embodiment, the description of the structure, operation, and effect is omitted. 9 and 10, the part obtained by adding the numeral 100 to the reference numerals in FIGS. 3 and 4 is the same as the part described in the first embodiment.

In the backlight device 124 according to the second embodiment, as shown in FIG. 9, the inclined surface 126a of the reflecting member 126 is formed so as to individually surround each LED light source 128 in an inverted quadrangular pyramid shape, and its circumferential direction is entirely As a square shape. Therefore, each LED light source 128 is surrounded by four inclined surfaces 126a inclined from the LED substrate 130 side to the front side, and the inclination angle of each inclined surface 126a is constant. As described above, when the LED light sources 128 are formed so as to surround each inclined surface 126a of the reflecting member 126 in an inverted quadrangular pyramid shape, the LED light sources 128 are formed so as to be surrounded in an inverted cone shape (Embodiment). 1), the reflective member 126 can be made excellent in shape stability.

Further, in the backlight device 124 according to the second embodiment, a plurality of the same light shielding patterns 125 are printed on the back surface (surface facing the LED light source 128) 120a of the diffusion plate 120 by inkjet printing over the entire surface. Each light shielding pattern 125 is formed in a dot shape composed of

quadruple squares

125a, 125b, 125c, and 125d, and the print density gradually decreases from the innermost square 125a toward the outermost circle 125d. . A portion where the printing density of the light shielding pattern 125 is high has a high reflectance (low transmittance), and a portion where the printing density is low has a low reflectance (high transmittance). The relative positions of the light shielding patterns 125 and the LED light sources 128 are adjusted so that the portions with the highest print density are positioned in the front direction of the LED light sources 128.

Therefore, in the backlight device 124 according to the second embodiment, all or a large part of the light incident on the diffusion plate 120 can be adjusted by the light shielding pattern 125 printed on the diffusion plate 120, and the display surface of the liquid crystal panel 116 can be adjusted. Brightness unevenness can be prevented or suppressed. Further, since each of the plurality of light shielding patterns 125 includes a plurality of dot-shaped layers having different printing densities, each light shielding pattern 125 can be formed in a predetermined shape, and the light shielding pattern 125 to the diffusion plate 120 is formed. Can be efficiently printed. Furthermore, since each light shielding pattern 125 is printed on the diffusion plate 120 by inkjet printing, the light shielding pattern 125 can be efficiently printed on the diffusion plate 120.

<Embodiment 3>
Embodiment 3 will be described with reference to the drawings. FIG. 11 is a plan view of the backlight device 224 according to the third embodiment. FIG. 12 is a plan view of the diffusion plate 220 as viewed from the back side, and shows a plan view of the back surface 220 a of the diffusion plate 220. The third embodiment is different from that of the first embodiment in that the distance between the LED light sources 228 and the inclination angles of the inclined surfaces 226a1 and 226a2 of the reflecting member 226 are not constant. Since the other configuration is the same as that of the first embodiment, the description of the structure, operation, and effect is omitted. In FIG. 11, the part obtained by adding the numeral 200 to the reference numeral in FIG. 3 is the same as the part described in the first embodiment.

In the backlight device 224 according to the third embodiment, as shown in FIG. 11, the inclined surface 226a of the reflecting member 226 is formed so as to individually surround each LED light source 228 in an inverted quadrangular pyramid shape. And the space | interval of the adjacent LED light source 228 is not made constant, but the part where the space | interval is close | packed, and the part which is coarse are mixed. Further, the angles of the inclined surfaces 226a1 and 226a2 of the reflecting member 226 are adjusted according to the interval between the adjacent LED light sources 228. Specifically, in the nine LED light sources 228 located on the center side of the backlight device 224, the interval between the adjacent LED light sources 228 is close, and the inclined surface 226a1 of the reflecting member 226 surrounding the LED light sources 228 is included. Has become steep. On the other hand, in the six LED light sources 228 positioned on both ends in the horizontal direction of the backlight device 224, the interval between the adjacent LED light sources 228 is rough, and the inclined surface 226a2 of the reflecting member 226 surrounding the LED light sources 228 is formed. It is moderate.

On the other hand, a plurality of light shielding patterns 225 and 227 are printed on the back surface (surface facing the LED light source 228) 220a of the diffusion plate 220 by silk screen printing over the entire surface. The light shielding pattern 225 has a dot shape composed of

quadruple rectangles

225a, 225b, 225c, and 225d, and the light shielding pattern 227 has a dot shape composed of

quadruple squares

227a, 227b, 227c, and 227d. The light shielding pattern 225 is superimposed on the reflective member 226 a 2 and the LED light source 228 surrounded by the reflective member 226 a 2, and is printed so that the darkest part is located in the front direction of the LED light source 228. The light-shielding pattern 227 is superimposed on the reflective member 226a1 and the LED light source 228 surrounded by the reflective member 226a1, and is printed so that the darkest part is located in the front direction of the LED light source 228.

Since the backlight device 224 according to the third embodiment is configured as described above, the number of LED light sources 228 is reduced as compared with the backlight device 24 according to the first embodiment. Further, since the light shielding patterns 225 and 227 are printed on the diffusion plate 220 according to the reflection member 226 according to the interval between the LED light sources 228, the number of the light shielding patterns 225 and 227 is also reduced. And even if it is a case where the space | interval of each LED light source 228 differs because the inclination | tilt angle of each inclined surface 226a1, 226a2 of the reflection member 226 is adjusted according to the space | interval of the adjacent LED light source 228, LED light source 228 is different. Many portions of the light emitted from the light can be incident on the surface of the diffusion plate 220 facing the LED light source 228 from the front direction. Therefore, the backlight device 224 can reduce the number of the LED light sources 228 and the light shielding patterns 225 and 227 while preventing or suppressing luminance unevenness on the display surface of the liquid crystal panel. The power consumption of the light device 224 can be further reduced.

The correspondence between the configuration of each embodiment and the configuration of the present invention is described. The

LED light sources

28, 128, and 228 are examples of “light sources”. The

backlight devices

24, 124, and 224 are examples of “illumination devices”.

The modifications of the above embodiments are listed below.
(1) In each of the above-described embodiments, a configuration in which the light shielding pattern is formed of a plurality of striped or dot layers is employed, but a configuration in which the light shielding pattern is formed in another shape may be employed.

(2) In each of the above embodiments, a configuration in which a plurality of light shielding patterns are printed on the diffusion plate is adopted. However, a configuration in which one or a small number of light shielding patterns including a plurality of layers is printed on the diffusion plate is employed. May be.

(3) Besides the gravure printing, ink jet printing, and silk screen printing employed in each of the above embodiments, the printing method of the light shielding pattern can be appropriately changed.

(4) In each of the above embodiments, a configuration is adopted in which only the edge portion of the diffusion plate is supported. However, the diffusion plate is attached to the bottom plate of the chassis, extends from the bottom plate to the diffusion plate side, and the tip thereof is the back surface of the diffusion plate. A configuration in which a support pin that supports the diffusion plate by abutting is provided may be adopted.

(5) In addition to the above embodiments, the shape and the like of the reflecting member can be appropriately changed.

(6) In each of the above embodiments, a liquid crystal display device using a liquid crystal panel as the display panel has been illustrated, but the present invention can also be applied to display devices using other types of display panels.

(7) In each of the above embodiments, a television receiver provided with a tuner has been exemplified. However, the present invention can also be applied to a display device that does not include a tuner.

As mentioned above, although each embodiment of the technique disclosed by this specification was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

Further, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

TV: TV receiver, Ca, Cb: cabinet, T: tuner, S: stand, 10: liquid crystal display, 12: bezel, 14: frame, 16: liquid crystal panel, 18: optical member, 20, 120, 220: Diffusion plate, 20a, 120a, 220a: back surface (of diffusion plate) 22, 222: chassis, 24, 124, 224: backlight device, 25, 125, 225, 227: light shielding pattern, 26, 126, 226: reflection Member, 26a, 126a, 226a1, 226a2: inclined surface, 28, 128, 228: LED light source, 30: LED substrate

Claims

A light source having a light distribution such that light having a peak emission intensity is directed in a direction inclined with respect to the front direction;
A chassis that houses the light source and opens toward the light exit side;
A reflective member that has a plurality of inclined surfaces that are inclined from the installation surface of the light source toward the opening side of the chassis, and that directs light from the light source in the front direction of the light source by the inclined surface;
A diffusion plate disposed on the opening side of the chassis and having a light-shielding pattern printed on a surface facing the light source;
A lighting device comprising:
The lighting device according to claim 1, wherein a plurality of the light shielding patterns are printed on the entire surface of the diffusion plate facing the light source.
Each of the plurality of light-shielding patterns has a different degree of light-shielding depending on the print density, and the print density is adjusted according to the luminance of light incident on the light-shielding pattern. Item 3. The lighting device according to Item 2.
4. The illumination device according to claim 3, wherein each of the plurality of light shielding patterns has a plurality of portions having different printing densities.
5. The lighting device according to claim 4, wherein each of the plurality of light shielding patterns includes a plurality of striped or dot layers having different printing densities.
The angle of the inclined surface of the reflecting member with respect to the front direction of the light source is smaller than the angle formed with respect to the front direction of light from the light source that has a peak emission intensity. The lighting device according to any one of claims 1 to 5, wherein:
The illumination according to any one of claims 1 to 6, wherein the light shielding pattern is printed on the diffusion plate by any one of gravure printing, ink jet printing, and silk screen printing. apparatus.
The lighting device according to any one of claims 1 to 7, wherein the reflecting member has a shape in which the inclined surface individually surrounds the light source.
The lighting device according to any one of claims 1 to 8, wherein the reflecting member has a plurality of inclined angles that are constant.
The lighting device according to any one of claims 1 to 9, wherein an interval between the adjacent light sources is constant.
The interval between the adjacent light sources is not constant, and the inclination angles of the plurality of inclined surfaces of the reflecting member are respectively adjusted according to the interval between the adjacent light sources. The lighting device according to claim 8.
A display device comprising a display panel that performs display using light from the illumination device according to any one of claims 1 to 11.
The display device according to claim 12, wherein the display panel is a liquid crystal panel using liquid crystal.
A television receiver comprising the display device according to claim 12 or 13.