IMAGE DISPLAY DEVICE

1 . An image display device, comprising:

at least one screen;

an image projector for projecting an image on the screen; and

a control unit that periodically switches between a light-transmitting state and a light-scattering state of the screen,

wherein:

the screen comprises: a pair of oppositely disposed substrates having an electrode, at least one of which is a transparent substrate, and 7a liquid crystal light modulating layer provided between the pair of substrates having an electrode, the liquid crystal light modulating layer comprising a complex comprising a chiral nematic liquid crystal phase of positive dielectric constant anisotropy, and a solid phase of polymeric resin;

the screen is in a light-transmitting state under no applied voltage, and is switchable to a light-scattering state in response to applied voltage;

the screen and the image projector are synchronized such that the image projector projects an image on a part of the screen or on the whole screen when the screen is in a light-scattering state, and projects no image when the screen is in a light-transmitting state; and

the control unit controls the periodic switching so that a switching frequency is 40 Hz to 100 Hz, and a light-scattering state duty ratio is 0.01 to 0.20.

2 . The image display device according to claim 1 , wherein the periodic switching is performed at τ ON /(τ ON +τ OFF ) of 0.01 to 0.20, where τ OFF is a time with a parallel light transmittance of 30% or more, and τ ON is a time with a parallel light transmittance of less than 30%.

3 . The image display device according to claim 1 , wherein the screen has a rise response time τ 1 of 3.0 ms or less, and a fall response time τ 2 of 3.0 ms or less in the process of changing from the light-transmitting state to the light-scattering state and returning to the light-transmitting state when a burst voltage at a frequency of 40 Hz to 100 Hz and a duty ratio of 0.01 to 0.20 is applied to the screen.

4 . The image display device according to claim 1 , wherein the screen has a haze of 20% or less in a light-scattering state portion under an applied burst voltage having a frequency of 40 Hz to 100 Hz and a duty ratio of 0.01 to 0.20.

5 . The image display device according to claim 1 , wherein the screen has a haze of 10% or less under no applied voltage.

6 . The image display device according to claim 1 , wherein, when being synchronized such that the image projector projects an image on a part of the screen or on the whole screen when the screen is in a light-scattering state, and projects no image when the screen is in a light-transmitting state, and being driven to periodically switch between the light-transmitting state and the light-scattering state,

a white display-to-black display radiance ratio is 30 or more in all angles within a 30° angle with respect to an incident direction of an image projected by the image projector and falling on the screen.

7 . The image display device according to claim 1 , wherein the chiral nematic liquid crystal has a chiral pitch p of 0.3 μm to 3 μm.

8 . The image display device according to claim 1 , wherein the ratio d/p of the distance d between the substrates having an electrode, and the chiral pitch p of the chiral nematic liquid crystal is 1 or more.

9 . The image display device according to claim 1 , wherein the liquid crystal light modulating layer is obtained by photo-curing a mixture of the chiral nematic liquid crystal of positive dielectric constant anisotropy and a polymer precursor represented by the following general formula (1):

wherein:

A 1 and A 2 each independently represent a hydrogen atom or methyl;

Ar 1 , Ar 2 , and Ar 3 each independently represent an optionally substituted bivalent aromatic hydrocarbon group, or an optionally substituted bivalent heterocyclic aromatic group;

X 1 and X 2 each independently represent a direct bond, a carbon double bond, a carbon triple bond, an ether bond, an ester bond, optionally substituted linear alkylene of 1 to 6 carbon atoms, or optionally substituted linear oxyalkylene of 1 to 6 carbon atoms;

R 1 and R 2 each independently represent optionally substituted linear alkylene of 1 to 6 carbon atoms, optionally substituted linear oxyalkylene of 1 to 6 carbon atoms, or linear alkyl ester of 2 to 6 carbon atoms;

m, n, p, and q each independently represent 0 or 1; and

at least one of Ar 1 , Ar 2 and Ar 3 represents an optionally substituted bivalent fused aromatic hydrocarbon group or an optionally substituted bivalent heterocyclic aromatic group.

10 . The image display device according to claim 9 , wherein the polymer precursor represented by the general formula (1) is represented by the following general formula (2)

wherein:

A 1 and A 2 each independently represent a hydrogen atom or methyl;

Ar 4 represents an optionally substituted bivalent fused aromatic hydrocarbon group, or an optionally substituted bivalent fused aromatic heterocyclic group;

R 1 and R 2 each independently represent optionally substituted linear alkylene of 1 to 6 carbon atoms, optionally substituted linear oxyalkylene of 1 to 6 carbon atoms, or linear alkyl ester of 2 to 6 carbon atoms; and

p and q each independently represent 0 or 1.

11 . The image display device according to claim 10 , wherein Ar 4 in the general formula (2) is an optionally substituted bivalent naphthalene ring.

12 . A screen that is in a light-transmitting state under no applied voltage, and that is switchable to a light-scattering state in response to applied voltage, wherein:

the screen periodically switches between a light-transmitting state and a light-scattering state, and has a haze of 20% or less in a light-scattering state portion under an applied burst voltage having a switching frequency of 40 Hz to 100 Hz and a periodic switching duty ratio of 0.01 to 0.20; and

the screen comprises: a pair of oppositely disposed substrates having an electrode, at least one of which is transparent; and a liquid crystal light modulating layer provided between the pair of substrates having an electrode, the liquid crystal light modulating layer comprising a complex comprising a chiral nematic liquid crystal phase of positive dielectric constant anisotropy, and a solid phase of polymeric resin.