OPTICAL SHEET, SCREEN, AND DISPLAY APPARATUS

• US 20180275480A1
• Filed: 10/07/2016
• Published: 09/27/2018
• Est. Priority Date: 10/08/2015
• Status: Active Grant

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: KUBOTA, Shogo, KURASHIGE, Makio, NAKATSUGAWA, Kaori
• Granted Patent: US 10,656,495 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 26/026 based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays based on orientable dipolar particles G02F1/172; based on electrophoresis G02F1/167
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02F 1/19 based on variable-reflection or variable-refraction elements not provided for in groups G02F1/015 - G02F1/169
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03B 21/62 Translucent screens
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 9/31 Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]

Abstract

An optical sheet, a screen, and a display apparatus capable of reducing speckles are provided. An optical sheet (50) includes a particle layer (55) including a transparent retaining part (56) having a predetermined thickness and a particle (60) that is accommodated in a cavity (56a) formed in the retaining part (56) and includes a first portion (61) and a second portion (62) having different dielectric constants. The first portion (61) includes a transparent first main portion (66a) and a first diffusion component (66b) that diffuses light. The second portion (62) includes a transparent second main portion (67a) and a second diffusion component (67b) that diffuses light. The first diffusion component (66b) and the second diffusion component (67b) have a diameter d satisfying the following conditional expression (1): 0.1 μm≤d≤15 μm (1).

Claims

1. An optical sheet comprising a particle layer including

a transparent retaining part that has a predetermined thickness, and

a particle that is accommodated in a cavity formed in the retaining part and includes a first portion and a second portion having different dielectric constants, wherein

the first portion includes a transparent first main portion and a first diffusion component that diffuses light,

the second portion includes a transparent second main portion and a second diffusion component that diffuses light, and

the first diffusion component and the second diffusion component have a diameter d satisfying the following conditional expression (1):

0.1 μ

m<

d<

15 μ

m  

 

(1)

2. The optical sheet according to claim 1, wherein a volume fraction Vi indicating a proportion of a sum of volumes of the first diffusion component and the second diffusion component to a volume of the particle satisfies the following conditional expression (2):

Vi≥

3%  

 

(2)

3. The optical sheet according to claim 2, wherein a refractive index difference Δ

n between the first and second diffusion components and the first and second main portions satisfies the following conditional expression (3);

|Δ

n|<

0.2  

 

(3)

4. A screen comprising:

the optical sheet according to claim 1; and

an electrode that forms an electric field for driving the particle of the particle layer when a voltage is applied thereto.

5. The screen according to claim 4, wherein the electrode has a function of diffusing and reflecting light as a diffuse reflection layer.

6. A display apparatus comprising:

the screen according to claim 4; and

a projector that irradiates the screen with coherent light.

7. The display apparatus according to claim 6, further comprising:

a power source that applies a voltage to the electrode of the screen; and

a control device that controls an applied voltage from the power source to the electrode, wherein

the control device controls the applied voltage from the power source to operate the particle in the particle layer.

8. The display apparatus according to claim 7, wherein the control device controls the applied voltage from the power source to repeatedly rotate the particle within an angular range of less than 180°

.

9. The display apparatus according to claim 7, wherein the control device controls at least either one of a direction and a position of the particle by the applied voltage from the power source so that the first portion covers at least part of the second portion from an observer side along a normal direction of the screen.

10. A screen comprising:

the optical sheet according to claim 2; and

an electrode that forms an electric field for driving the particle of the particle layer when a voltage is applied thereto.

11. A screen comprising:

the optical sheet according to claim 3; and

an electrode that forms an electric field for driving the particle of the particle layer when a voltage is applied thereto.

12. A display apparatus comprising:

the screen according to claim 5; and

a projector that irradiates the screen with coherent light.

13. The display apparatus according to claim 8, wherein the control device controls at least either one of a direction and a position of the particle by the applied voltage from the power source so that the first portion covers at least part of the second portion from an observer side along a normal direction of the screen.