DISPLAY DEVICE

• US 20170242302A1
• Filed: 02/24/2017
• Published: 08/24/2017
• Est. Priority Date: 02/24/2016
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: ASAKAWA, Youichi, FUKUMA, Toshihiko, ONODA, Ken, KOMURA, Shinichi
• Granted Patent: US 10,324,335 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 2413/03 Number of plates being 3
• CPC Class Codes: G02F 2413/07 All plates on one side of the LC cell

Abstract

According to one embodiment, a display device includes a display panel including a first substrate, a second substrate, and an optical element layer provided between the substrates, a light directing unit facing the first substrate of the display panel, and including a first main surface disposed on a side facing the first substrate, and a second main surface disposed on a side reverse to the first main surface, and a light source unit disposed on the first substrate side with respect to the display panel, and emitting polarized light toward the first or second main surface. The polarized light is made incident on the first or second main surface, and directed perpendicularly to the optical element layer.

Claims

1. A display device comprising:

a display panel including a first substrate, a second substrate facing the first substrate, and an optical element layer provided between the first substrate and the second substrate;

a light directing unit facing the first substrate of the display panel, and including a first main surface disposed on a side facing the first substrate, and a second main surface disposed on a side reverse to the first main surface; and

a light source unit disposed on the first substrate side with respect to the display panel, and emitting polarized light toward the first main surface or the second main surface,

wherein the polarized light is made incident on the first main surface or the second main surface, and directed perpendicularly to the optical element layer.

2. The display device according to claim 1, wherein

the first main surface is inclined with respect to the display panel,

the first main surface is covered with a reflection layer reflecting the polarized light, and the polarized light is made incident on the first main surface from the display panel side, and reflected by the first main surface.

3. The display device according to claim 1, wherein

the first main surface has an uneven shape,

the uneven shape is covered with the reflection layer reflecting the polarized light, and

the polarized light is made incident on the first main surface from the display panel side, and reflected by the first main surface.

4. The display device according to claim 1, wherein

the second main surface has an uneven shape, and

the polarized light is made incident on inside of the light directing unit from the second main surface, and refracted and reflected by the second main surface.

5. The display device according to claim 3, further comprising:

first prism portions forming the uneven shape, wherein

each of the first prism portions has a triangular cross section, and includes a first slope, and a second slope disposed distant from the light source unit beyond the first slope.

6. The display device according to claim 4, further comprising:

first prism portions forming the uneven shape, wherein

each of the first prism portions has a triangular cross section, and includes a first slope, and a second slope disposed distant from the light source unit beyond the first slope.

7. The display device according to claim 5, wherein a top line of each of the first prism portions has an arc shape projecting reverse to a side on which the light source is disposed.

8. The display device according to claim 6, wherein a top line of each of the first prism portions has an arc shape projecting reverse to a side on which the light source is disposed.

9. The display device according to claim 5, further comprising:

second prism portions forming the uneven shape, wherein

each of the second prism portions has a triangular cross section, and includes a third slope, and a fourth slope disposed distant from the light source unit beyond the third slope,

the second prism portions are disposed distant from the light source unit beyond the first prism portions; and

the first slope has a tilt angle smaller than a tilt angle of the third slope.

10. The display device according to claim 7, further comprising:

second prism portions forming the uneven shape, wherein

each of the second prism portions has a triangular cross section, and includes a third slope, and a fourth slope disposed distant from the light source unit beyond the third slope,

the second prism portions are disposed distant from the light source unit beyond the first prism portions; and

the first slope has a tilt angle smaller than a tilt angle of the third slope.

11. The display device according to claim 7, further comprising:

a first retardation plate disposed between the light directing unit and the display panel; and

a first polarizer disposed between the first retardation plate and the display panel,

wherein the polarized light passes through the first retardation plate and the first polarizer in this order, and

the first retardation plate rotates a polarization direction of the passing light to be parallel with a transmission axis direction of the first polarizer.

12. The display device according to claim 8, further comprising:

a first retardation plate disposed between the light directing unit and the display panel; and

a first polarizer disposed between the first retardation plate and the display panel,

wherein the polarized light passes through the first retardation plate and the first polarizer in this order, and

the first retardation plate rotates a polarization direction of the passing light to be parallel with a transmission axis direction of the first polarizer.

13. The display device according to claim 9, further comprising:

a first retardation plate disposed between the light directing unit and the display panel; and

a first polarizer disposed between the first retardation plate and the display panel,

wherein the polarized light passes through the first retardation plate and the first polarizer in this order, and

the first retardation plate rotates a polarization direction of the passing light to be parallel with a transmission axis direction of the first polarizer.

14. The display device according to claim 1, further comprising:

a second retardation plate disposed between the light source unit and the light directing unit;

a third retardation plate disposed between the display panel and the light directing unit; and

a first polarizer disposed between the display panel and the second retardation plate,

wherein each of the second retardation plate and the third retardation plate is a ¼

wavelength plate, and the polarized light passes through the second retardation plate, the third retardation plate, and the first polarizer in this order.

15. The display device according to claim 3, further comprising:

a second retardation plate disposed between the light source unit and the light directing unit;

a third retardation plate disposed between the display panel and the light directing unit; and

a first polarizer disposed between the display panel and the second retardation plate,

wherein each of the second retardation plate and the third retardation plate is a ¼

wavelength plate, and the polarized light passes through the second retardation plate, the third retardation plate, and the first polarizer in this order.

16. The display device according to claim 4, further comprising:

a second retardation plate disposed between the light source unit and the light directing unit;

a third retardation plate disposed between the display panel and the light directing unit; and

a first polarizer disposed between the display panel and the second retardation plate,

wherein each of the second retardation plate and the third retardation plate is a ¼

wavelength plate, and the polarized light passes through the second retardation plate, the third retardation plate, and the first polarizer in this order.

17. The display device according to claim 11, wherein

the first retardation plate is a ½

wavelength plate, and

the first retardation plate has slow axes that are line-symmetrical with respect to a center line of a luminous flux of the polarized light in plan view, and different according to a position with respect to the center line.

18. The display device according to claim 13, wherein

the first retardation plate is a ½

wavelength plate, and

the first retardation plate has slow axes that are line-symmetrical with respect to a center line of a luminous flux of the polarized light in plan view, and different according to a position with respect to the center line.

19. The display device according to claim 1, further comprising:

a light diffusion layer facing the second substrate of the display panel, and diffusing light,

wherein the polarized light is applied to the light diffusion layer after passing through the optical element layer.

20. The display device according to claim 1, wherein the polarized light is laser light with a main wavelength of 480 nm or less,

the display device further includes an emitting layer facing the second substrate of the display panel, and adsorbing the laser light to emit light,

the emitting layer includes a red phosphor layer and a green phosphor layer, and

the polarized light is applied to the emitting layer after passing through the optical element layer.