JP2021061133A - Lighting device and display device - Google Patents

Abstract

To provide a lighting device that can improve lighting quality, and to provide a display device.SOLUTION: A lighting device includes: a light guide plate including a first primary surface, a second primary surface opposed to the first primary surface in a first direction, a first lateral surface positioned between the first primary surface and the second primary surface, and a slow axis parallel to the first direction at the first primary surface or a second direction orthogonal to the first direction; and a first light source for emitting a laser beam having a polarization direction crossing with the first direction and the second direction respectively at the first lateral surface to the first lateral surface.SELECTED DRAWING: Figure 4

Description

Embodiments of the present invention relate to lighting devices and display devices.

A display device such as a liquid crystal display device includes a display panel having pixels and a lighting device such as a backlight unit that illuminates the display panel. The lighting device includes a light source that emits light and a light guide plate that is irradiated with light from this light source. The light from the light source enters the light guide plate from the side surface of the light guide plate, propagates in the light guide plate, and is emitted from an exit surface corresponding to one main surface of the light guide plate. As an example, a lighting device in which a point light source that emits a laser beam is arranged near the side surface of the light guide plate is disclosed.

JP-A-2018-45990

An object of the present embodiment is to provide a lighting device and a display device capable of improving the lighting quality.

According to this embodiment
The first main surface, the second main surface facing the first main surface in the first direction, the first side surface located between the first main surface and the second main surface, and the first side surface. A light guide plate having a slow axis parallel to the first direction or a second direction orthogonal to the first direction, and polarization crossing each of the first direction and the second direction on the first side surface. An illuminating device comprising a first light source that emits a directional laser beam to the first side surface is provided.
According to this embodiment
A light guide plate having a first main surface, a second main surface facing the first main surface, and a first side surface located between the first main surface and the second main surface, and a first A first light source that emits a laser beam of a first color having a polarization direction to the first side surface, and a laser light of the first color that emits a laser beam of the first color having a second polarization direction to the first side surface and adjacent to the first light source. Provided is an illuminating device comprising a matching second light source and having the first polarization direction intersecting the second polarization direction on the first side surface.
According to this embodiment
A light guide plate having a plurality of light sources for emitting laser light having a first polarization direction, a side surface facing the plurality of light sources, and a first main surface for emitting light incident from the side surface, and the plurality of light sources. Provided is an illuminating device including a polarizing element located between a light source and the side surface and changing the polarization state of the laser light emitted by the plurality of light sources.

FIG. 1 is an exploded perspective view showing a display device including the lighting device of one embodiment. FIG. 2 is a cross-sectional view of the display device shown in FIG. FIG. 3 is a diagram for explaining a first configuration example of the above embodiment, and is a plan view showing the light guide plate shown in FIG. 1 and a plurality of light sources. FIG. 4 is a side view of the light guide plate when the side surface of the light guide plate is viewed from the light source shown in FIG. FIG. 5 is a diagram for explaining a second configuration example of the above embodiment, and is a side view of the light guide plate when the side surface of the light guide plate is viewed from a light source. FIG. 6 is a diagram for explaining a third configuration example of the above embodiment, and is a side view of the light guide plate when the side surface of the light guide plate is viewed from a light source. FIG. 7 is a diagram for explaining a fourth configuration example of the above embodiment, and is a plan view showing a light guide plate, a plurality of light sources, and a polarizing element. FIG. 8 is a diagram for explaining a fifth configuration example of the above embodiment, and is a plan view showing a light guide plate, a plurality of light sources, and a polarizing element. FIG. 9 is a diagram for explaining a fifth configuration example of the above embodiment, and is a diagram showing the relationship between the wavelength of light incident on the polarizing element shown in FIG. 8 and the transmittance. FIG. 10 is a diagram for explaining a sixth configuration example of the above embodiment, and is shown by (a) a plan view showing a light source LS and a polarizing element PR, and (b) a partial cross-sectional view of the polarizing element PR. It is a figure.

Hereinafter, the present embodiment will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate changes while maintaining the gist of the invention are naturally included in the scope of the present invention. Further, in order to clarify the description, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is merely an example, and the present invention is provided. It does not limit the interpretation. Further, in the present specification and each figure, components exhibiting the same or similar functions as those described above with respect to the above-mentioned figures may be designated by the same reference numerals, and duplicate detailed description may be omitted as appropriate. ..

In the present embodiment, a transmissive liquid crystal display device will be described as an example of the display device DSP. The main configuration disclosed in the present embodiment is a liquid crystal display device, an electrophoresis element, etc. having a reflection type function of reflecting external light and using the reflected light for display in addition to the transmission type function. It can also be applied to an electronic paper type display device having the above, a display device to which MEMS (Micro Electro Mechanical Systems) is applied, a display device to which electrochromism is applied, and the like.

FIG. 1 is an exploded perspective view of a display device DSP including the lighting device IL of one embodiment.
As shown in FIG. 1, the directions X, Y, and Z are orthogonal to each other, but may intersect at an angle other than 90 degrees. The direction X and the direction Y correspond to the directions parallel to the main surface of the substrate constituting the display device DSP, and the direction Z corresponds to the thickness direction of the display device DSP. In the present specification, the direction from the first substrate SUB1 to the second substrate SUB2 is referred to as "upper side" (or simply upper), and the direction from the second substrate SUB2 to the first substrate SUB1 is referred to as "lower side" (or simply upper side). Simply referred to as below).
The display device DSP includes a display panel PNL, a lighting device IL, an IC chip 1, and a wiring board 2.

The display panel PNL includes a first substrate SUB1 and a second substrate SUB2. The display panel PNL has a display area DA for displaying an image. The display panel PNL includes, for example, a plurality of pixels PX arranged in a matrix in the display area DA.

The IC chip 1 and the wiring board 2 may read a signal from the display panel PNL, but mainly function as a signal source for supplying a signal to the display panel PNL. These signal sources are mounted on one portion of the display panel PNL where the first substrate SUB1 is exposed from the second substrate SUB2. The IC chip 1 may be mounted on the wiring board 2. The wiring board 2 is, for example, a bendable flexible printed circuit board.

The illuminating device IL illuminates the display panel PNL. The lighting device IL includes a light guide plate LG and a plurality of light sources LS (LS10, LS11, ..., LS20, LS21, ... LS30, LS31, ...). The light guide plate LG, the first substrate SUB1 and the second substrate SUB2 are arranged in this order along the direction Z.

The light guide plate LG is formed in a flat plate shape parallel to the XY plane defined by the direction X and the direction Y, for example. The light guide plate LG has a main surface 1A facing the display panel PNL, a main surface 1B facing the main surface 1A in the direction Z, and a side surface SF10 located between the main surface 1A and the main surface 1B. ing.
The plurality of light sources LS face the side surface SF10. The main surface 1A is a surface on which light incident from the side surface SF10 is emitted. Although not shown, a plurality of prisms are formed on the main surface 1B to change the traveling direction of the light traveling in the light guide plate LG. The plurality of prisms may be formed on the main surface 1A.

The light guide plate LG is formed of, for example, a transparent resin such as polymethyl methacrylate (PMMA) having negative birefringence. The light guide plate LG is manufactured by, for example, an extrusion molding method or an injection molding method. The light guide plate LG has birefringence, and in the illustrated example, it has a slow axis AX1 parallel to the direction Z and a phase advance axis AX2 parallel to the direction X. The slow-phase axis AX1 and the phase-advance axis AX2 are orthogonal to each other. The slow-phase axis AX1 is, for example, the direction in which the light guide plate LG on the side surface SF10 has the largest refractive index. The light guide plate LG may have a slow axis AX1 parallel to the direction X and a phase advance axis AX2 parallel to the direction Z.

The plurality of light sources LS are arranged at intervals along the direction X. Each light source LS faces the side surface SF10. The light source LS is, for example, a laser light source such as a semiconductor laser that emits polarized laser light. The light source LS may be a light source of a plurality of colors that emit light of different colors, for example, a white laser light is obtained by mixing the light emitted from each of the red laser light source, the green laser light source, and the blue laser light source. Can be done. However, the plurality of light sources LS may have two color light sources or may have four or more color light sources. In the present specification, the plurality of light sources LS10, LS11, ... Emit a laser beam having a red wavelength, the plurality of light sources LS20, LS21, ... Emit a laser beam having a green wavelength, and the plurality of light sources LS30, LS31 ... Are blue. Emits a laser beam of wavelength. In the illustrated example, the plurality of light sources LS10, LS11, ... Are arranged along the X direction, the plurality of light sources LS20, LS21, ... Are arranged along the X direction, and the plurality of light sources LS30, LS31 ... Are arranged along the X direction. The light sources that emit laser light of the same color are lined up at intervals in the X direction.

FIG. 2 is a cross-sectional view of the display device DSP shown in FIG.
As shown in FIG. 2, the display panel PNL further includes a liquid crystal layer LC, a seal SE, a polarizing plate PL1, and a polarizing plate PL2.

The liquid crystal layer LC and the seal SE are located between the first substrate SUB1 and the second substrate SUB2. The seal SE adheres the first substrate SUB1 and the second substrate SUB2 and seals the liquid crystal layer LC. The polarizing plate PL1 is adhered to the lower surface of the first substrate SUB1. The polarizing plate PL2 is adhered to the upper surface of the second substrate SUB2. The polarizing plate PL1 and the polarizing plate PL2 are formed mainly of, for example, polyvinyl alcohol (PVA), absorb a specific polarizing component of light, and transmit other polarizing components. The transmission axis of the polarizing plate PL1 and the transmission axis of the polarizing plate PL2 are, for example, orthogonal to each other.

The lighting device IL further includes a diffusion sheet DS and an antiprism sheet PS. The diffusion sheet DS is located between the display panel PNL and the light guide plate LG. The diffusion sheet DS diffuses the light incident on the diffusion sheet DS to make the brightness of the light uniform. The reverse prism sheet PS is located between the diffusion sheet DS and the light guide plate LG, and has a plurality of prism portions PA protruding toward the main surface 1A. In the illustrated example, the prism portion PA has a triangular cross section parallel to the YZ plane and extends in the direction X. The prism portion PA may be composed of a dot pattern or an uneven surface. The antiprism sheet PS collects the light emitted from the main surface 1A of the light guide plate LG, for example, in the direction Z.

Next, the laser beam L emitted from the light source LS will be described. The light source LS is separated from the side surface SF10. The laser beam L emitted from the light source LS is refracted by the side surface SF10 and incident on the light guide plate LG. Of the laser light L incident on the light guide plate LG, the light traveling toward the main surface 1A is reflected at the interface between the light guide plate LG and the air layer. Further, of the laser light L incident on the light guide plate LG, the light traveling toward the main surface 1B is reflected at the interface between the light guide plate LG and the air layer. In this way, the incident laser light L travels in the light guide plate LG while being repeatedly reflected by the main surfaces 1A and 1B. The light traveling in the light guide plate LG is changed in the traveling direction by a prism on the main surface 1B, for example, and is emitted from the main surface 1A outside the total reflection condition of the main surface 1A. The light emitted from the main surface 1A illuminates the display panel PNL via the light guide plate LG, the antiprism sheet PS, and the diffusion sheet DS.

Pay attention to the degree of polarization of the light emitted from the illuminating device IL and illuminating the display panel PNL. The degree of polarization is a quantity representing the degree of polarization. The light emitted from the illuminating device IL is incident on the polarizing plate PL1. Assuming that the light transmittance of the polarizing plate PL1 is the transmittance BT and the light absorption rate of the polarizing plate PL1 is the absorption rate BA, the degree of polarization BP of the light incident on the polarizing plate PL1 can be expressed by the following equation.
BP = (BT-BA) / (BT + BA)
For example, when the degree of polarization BP of the light incident on the polarizing plate PL1 is 100, the transmittance BT is 100 and the absorption rate BA is 0. This is because the light incident on the polarizing plate PL1 is polarized in the same direction as the transmission axis of the polarizing plate PL1. When the degree of polarization BP of the light incident on the polarizing plate PL1 is 0, the transmittance BT is 50 and the absorption rate BA is 50. This is because, for example, the light incident on the polarizing plate PL1 is circularly polarized light, which is a polarized state close to natural light. The light incident on the polarizing plate PL1 is not necessarily circularly polarized light, but may be linearly polarized light inclined in an oblique direction depending on the phase.

Compared with a regular prism sheet (for example, a prism sheet having a prism portion protruding in the direction of the arrow in the direction Z), the inverted prism sheet PS collects the incident light without reflecting much, so that the reflected light is repeatedly reflected. There is little light that becomes stray light without being emitted from the light guide plate or light that is emitted in a direction that does not contribute to the front brightness. As a result, the light focused by the antiprism sheet PS has higher emission efficiency and front luminance than the light focused by the normal prism sheet. On the other hand, the light focused by the antiprism sheet PS has a non-uniform polarization distribution. If the polarization degree distribution of the light emitted by the illuminating device IL toward the display panel PNL (polarizing plate PL1) is non-uniform, the brightness distribution of the light transmitted through the polarizing plate PL1 and contributing to the display becomes non-uniform. The display quality of the display device DSP deteriorates.
In the present embodiment, the lighting device IL capable of suppressing the non-uniformity of the polarization degree distribution of light and the display device DSP incorporating the lighting device IL are provided.

FIG. 3 is a diagram for explaining a first configuration example of the above embodiment, and is a plan view showing the light guide plate LG shown in FIG. 1 and a plurality of light sources LS.
As shown in FIG. 3, each light source LS emits light to the side surface SF10.
The laser beam L10 emitted from the light source LS10 is linearly polarized light and has a polarization direction PD10. The intensity of the laser light L10 is the highest on the optical axis LX10, and the laser light L10 travels while spreading in the direction Y. The laser beam L20 emitted from the light source LS20 is linearly polarized light and has a polarization direction PD20. The intensity of the laser light L20 is the highest on the optical axis LX20, and the laser light L20 travels while spreading in the direction Y. The laser beam L30 emitted from the light source LS30 is linearly polarized light and has a polarization direction PD30. The intensity of the laser light L30 is the highest on the optical axis LX30, and the laser light L30 travels while spreading in the direction Y. In the illustrated example, the polarization direction PD10, the polarization direction PD20, and the polarization direction PD30 are substantially the same direction.

FIG. 4 is a side view of the light guide plate LG when the side surface SF10 of the light guide plate LG is viewed from the light source LS shown in FIG. FIG. 4 shows the polarization directions of the light guide plate LG and each light source LS. The polarization directions of the laser light emitted from the plurality of light sources LS10, LS11, ... Are the polarization directions PD10, PD11, ..., Respectively. The polarization directions of the laser beams emitted from the plurality of light sources LS20, LS21 ... Are the polarization directions PD20, PD21, ..., Respectively. The polarization directions of the laser light emitted from the plurality of light sources LS30, LS31, ... Are the polarization directions PD30, PD31, ..., Respectively.

The polarization direction PD10 intersects each of the direction Z and the direction X. In the illustrated example, the angle formed by the slow phase axis AX1 (direction Z) and the polarization direction PD10 on the side surface SF10 is an angle θ1. On the side surface SF10, the angle formed by the phase-advancing axis AX2 (direction X) and the polarization direction PD10 is an angle θ2. The angle θ1 and the angle θ2 are acute angles. In the illustrated example, the angle θ1 and the angle θ2 are 45 degrees. The angle θ1 and the angle θ2 may be 30 degrees or more and 60 degrees or less, respectively. In the illustrated example, the polarization direction of the laser light emitted from each light source LS is the same as the polarization direction PD10.

According to the first configuration example, the polarization direction PD10 of the laser beam L10 emitted from the light source LS10 intersects with each of the directions of the slow-phase axis AX1 of the light guide plate LG and the directions orthogonal to the slow-phase axis AX1. The polarization state of the laser light L10 incident on the light guide plate LG is changed from linearly polarized light to elliptically polarized light or circularly polarized light because the progress of the light is delayed in the direction of the slow axis AX1. The polarization state of the laser light emitted from the main surface 1A of the light guide plate LG is circularly polarized light or elliptically polarized light. For example, if the polarization state of the laser light emitted from the main surface 1A is uniformly substantially circularly polarized light, the degree of polarization BP of the light emitted from the illuminating device IL can be brought close to 0, so that the illuminating device IL It is possible to suppress the non-uniformity of the polarization degree distribution of the laser light emitted from the display panel PNL and illuminating the display panel PNL.

Further, since the light emitted from the light guide plate LG is collected by the antiprism sheet PS, the emission brightness of the lighting device IL is compared with the case where the light emitted from the light guide plate LG is collected by the positive prism sheet. And the front brightness of the display device DSP becomes high. As a result, it is possible to provide a lighting device capable of improving the lighting quality.

FIG. 5 is a diagram for explaining a second configuration example of the above embodiment, and is a side view of the light guide plate LG as seen from the light source LS on the side surface SF10 of the light guide plate LG. The second configuration example shown in FIG. 5 is different from the first configuration example shown in FIG. 4 in that the polarization directions of the laser beams of the same color emitted from adjacent light sources are different.

Focus on the interrelationship of the polarization directions (PD10, PD11, PD12) of the laser light of the same color. The polarization direction PD10 of the laser light emitted from the light source LS10 intersects with the polarization direction PD11 of the laser light emitted from the light source LS11 adjacent to the light source LS10. The polarization direction PD11 intersects with the polarization direction PD12 of the laser light emitted from the light source LS12 adjacent to the light source LS11. In the illustrated example, the polarization direction PD10 and the polarization direction PD11 intersect, but the angle between the polarization direction PD10 and the polarization direction PD11 may be 75 degrees or more and 90 degrees or less, preferably the polarization direction PD10. It is orthogonal to the polarization direction PD11. Similarly, the angle formed by the polarization direction PD11 and the polarization direction PD12 may be 75 degrees or more and 90 degrees or less, and the polarization direction PD11 and the polarization direction PD12 are preferably orthogonal to each other. When the polarization direction PD10 and the polarization direction PD11 are not orthogonal to each other, the polarization direction PD10 and the polarization direction PD12 do not have to be in the same direction. The interrelationship of the polarization directions (PD20, PD21, PD22) (PD30, PD31, PD32) of the laser light of other colors is the same as the interrelationship of the polarization directions (PD10, PD11, PD12) of the laser light.

According to the second configuration example, the polarization directions of the lasers emitted from adjacent light sources of the same color are different. When two laser beams having different polarization directions are combined, the polarization state of the laser beam becomes elliptically polarized light instead of linearly polarized light. Further, when the polarization directions of two different laser beams are orthogonal to each other, when the two different laser beams are combined, the polarization state of the laser beams becomes circularly polarized light. Further, depending on the phase, linearly polarized light is obtained so that the angle between the polarization directions of two laser beams having different polarization directions is obtained.
Even in such a configuration example, the same effect as that of the above configuration example can be obtained.

FIG. 6 is a diagram for explaining a third configuration example of the above embodiment, and is a side view of the light guide plate LG as seen from the light source LS on the side surface SF10 of the light guide plate LG. The third configuration example shown in FIG. 6 is different from the second configuration example shown in FIG. 5 in that the polarization direction PD10, the polarization direction PD20, and the polarization direction PD30 are arranged in the Z direction in this order. ing. Although not shown, the light source LS10, the light source LS20, and the light source LS30 are stacked in the Z direction.
Even in such a configuration example, the same effect as that of the above configuration example can be obtained.

FIG. 7 is a diagram for explaining a fourth configuration example of the above embodiment, and is a plan view showing a light guide plate LG, a plurality of light sources LS, and a polarizing element PR. The fourth configuration example shown in FIG. 7 is different from the first configuration example shown in FIG. 3 in that the lighting device IL includes a polarizing element PR between the plurality of light sources LS and the light guide plate LG. It is different.

The polarizing element PR is an element that changes the polarization state of incident light, and is, for example, a circular polarizing plate or a 1/4 wave plate in which a linear polarizing plate and a 1/4 wave plate are combined. As an example, the wavelength of the 1/4 wave plate is adjusted to the wavelength of green. When the polarizing element PR is a circular polarizing plate, the polarized state of the laser light incident on the polarizing element PR and emitted from the polarizing element PR is circularly polarized light. As a result, the polarization state of the laser light incident on the light guide plate LG is circularly polarized light.

When a 1/4 wave plate is used as the polarizing element PR, the angle formed by the polarization direction and the slow axis of the 1/4 wave plate is arranged so as to be 45 degrees. As a result, the polarized state of the laser light emitted from the polarizing element PR becomes circularly polarized light, and the circularly polarized laser light is incident on the light guide plate LG.
Even in such a configuration example, the same effect as that of the above configuration example can be obtained.

Next, a fifth configuration example of the present embodiment will be described with reference to FIGS. 8 and 9.
FIG. 8 is a plan view showing the light guide plate LG, the plurality of light sources LS, and the polarizing element PR. The fifth configuration example shown in FIG. 8 is different from the fourth configuration example shown in FIG. 7 in that the polarizing element PR is a birefringent element.

The polarizing element PR has super birefringence, and for example, Cosmo Shine (registered trademark) of Toyobo Co., Ltd. is preferably used. Here, the term "birefringence" means that the retardation in the in-plane direction with respect to light in the visible region, for example, 500 nm is 800 nm or more. Desirably, the in-plane retardation with respect to light of 500 nm is 8000 nm or more.

The wavelength WL20 of the laser light L20 emitted from the light source LS20, the wavelength WL22 of the laser light L21 emitted from the light source LS21, and the wavelength WL22 of the laser light L22 emitted from the light source LS22 are different from each other. As an example, the wavelength WL20 is 532 nm, the wavelength WL21 is 532.7 nm, and the wavelength WL22 is 533.4 nm.

FIG. 9 is a diagram showing the relationship between the wavelength of the laser light incident on the polarizing element PR shown in FIG. 8 and the transmittance. It should be noted that this figure shows the results of simulations of the above relationships by the inventors of the present application. In this simulation, the polarization direction of the laser light incident on the polarizing element PR and the anisotropy of the polarizing element PR (for example, the slow axis) are different by 45 degrees, and the polarizing plate is arranged on the emitted light side of the polarizing element PR. The polarizing plate has a transmission axis in a direction 90 degrees different from the polarization direction of the laser light incident on the polarizing element PR.

The horizontal axis shows the wavelength of the laser light incident on the polarizing element PR shown in FIG. 8, and the vertical axis shows the transmittance of the laser light emitted from the polarizing element PR with respect to the polarizing plate. For example, when a laser beam having a wavelength of 532 nm is incident on the polarizing element PR, the polarization state of the laser light emitted from the polarizing element PR is the same as the polarization state of the laser light incident on the polarizing element PR, and is transmitted to the polarizing plate. The rate is 0%. When light having a wavelength of 532.7 nm is incident on the polarizing element PR, the polarized state of the laser light emitted from the polarizing element PR becomes circularly polarized light, and the transmittance for the polarizing plate is 50%. When light having a wavelength of 533.4 nm is incident on the polarizing element PR, the polarization state of the laser light emitted from the polarizing element PR becomes linearly polarized light orthogonal to the linearly polarized light of the laser light incident on the polarizing element PR. The transmittance for the plate is 100%.

According to the fifth configuration example, the wavelengths of adjacent laser beams of the same color are different. As a result, each laser beam incident on the polarizing element PR, which is a birefringent, is emitted from the polarizing element PR in various polarized states. By mixing the laser beams in these various polarized states in the light guide plate LG, the degree of polarization BP of the light emitted from the illuminating device IL can be brought close to zero.
Even in such a configuration example, the same effect as that of the above configuration example can be obtained.

FIG. 10 is a diagram for explaining a sixth configuration example of the above embodiment, and is shown by (a) a plan view showing a light source LS and a polarizing element PR, and (b) a partial cross-sectional view of the polarizing element PR. It is a figure.
As shown in FIG. 10A, the polarizing element PR has a partial PP10 irradiated to the light source LS10. The polarizing element PR has at least two regions in the partial PP10 and has slow axes in at least two directions. In the illustrated example, the partial PP10 has six regions P1, P2, P3, P4, P5, P6. The polarizing element PR has a slow phase axis AX11 in the region P1, a slow phase axis AX12 in the region P2, a slow phase axis AX13 in the region P3, and a slow phase axis AX14 in the region P4. P5 has a slow-phase axis AX15, and region P6 has a slow-phase axis AX16.

The slow-phase axes AX11 to AX16 intersect with the polarization direction PD10, respectively. The polarization state of the laser light L1 incident on the region P1 is changed from linearly polarized light to elliptically polarized light or circularly polarized light because the progress of the light is delayed in the direction of the slow phase axis AX11. Similarly, the polarization state of the laser light L1 incident on each of the regions P2 to P5 is changed from linearly polarized light to elliptically polarized light or circularly polarized light because the progress of the light is delayed in the directions of the slow-phase axes AX12 to AX16, respectively. .. The degree of polarization BP of the light emitted from the illuminating device IL can be brought close to 0 by mixing the laser light emitted from the portion 10 in various polarized states in the light guide plate LG.
Even in such a configuration example, the same effect as that of the above configuration example can be obtained.

As described above, according to the present embodiment, it is possible to provide a lighting device and a display device capable of improving the lighting quality.
Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

DSP ... Display device IL ... Lighting device PNL ... Display panel
LG ... Light guide plate 1A, 1B ... Main surface SF10, SF20 ... Side AX ... Slow phase axis
LS ... Light source PD ... Polarization direction

Claims (10)

The first main surface, the second main surface facing the first main surface in the first direction, the first side surface located between the first main surface and the second main surface, and the first side surface. A light guide plate having a slow axis parallel to the first direction or a second direction orthogonal to the first direction.
A lighting device including a first light source that emits a laser beam having a polarization direction intersecting each of the first direction and the second direction on the first side surface to the first side surface. The lighting device according to claim 1, wherein the angle between the first direction and the polarization direction on the first side surface is 30 degrees or more and 60 degrees or less. A light guide plate having a first main surface, a second main surface facing the first main surface, and a first side surface located between the first main surface and the second main surface.
A first light source that emits a first-color laser beam having a first polarization direction to the first side surface,
A second light source that emits a laser beam of the first color having a second polarization direction to the first side surface and is adjacent to the first light source is provided.
An illuminating device in which the first polarization direction and the second polarization direction intersect in the first side surface. The lighting device according to claim 3, wherein the angle between the first polarization direction and the second polarization direction on the first side surface is 75 degrees or more and 90 degrees or less. A plurality of light sources that emit laser light having a first polarization direction,
A light guide plate having a side surface facing the plurality of light sources and a first main surface from which light incident from the side surface is emitted.
A lighting device including a polarizing element located between the plurality of light sources and the side surface and changing the polarization state of the laser light emitted by the plurality of light sources. The lighting device according to claim 5, wherein the polarizing element is a circular polarizing plate. The polarizing element is a birefringent element.
The plurality of light sources include a first light source that emits a laser beam of a first color and a second light source that emits a laser beam of the first color and is adjacent to the first light source.
The lighting device according to claim 5, wherein the wavelength of the laser light emitted from the first light source is different from the wavelength of the laser light emitted from the second light source. The plurality of light sources include a first light source that emits a laser beam having a first polarization direction in the first direction.
The polarizing element has a first portion that is irradiated with light from the first light source.
The lighting device according to claim 5, wherein the first portion has a plurality of regions having a slow phase axis parallel to a direction intersecting the first direction. The lighting device according to any one of claims 1 to 8, further comprising an antiprism sheet having a plurality of prism portions protruding toward the first main surface. Display panel and
A display device comprising the lighting device according to claim 9, which illuminates the display panel.

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