Display apparatus, driving method thereof, and screen apparatus for displaying

Patent metadata

Field	Value
Publication number	US-9785028-B2
Application number	US-201514831192-A
Country	US
Kind code	B2
Filing date	Aug 20, 2015
Priority date	Mar 23, 2012
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

To display an image and the back side image in an overlapped state on a screen, with good visibility and see-through capability. The screen scanned with an image light from the projector has an optical layer and a plurality of control electrodes which are arranged side by side along the optical layer. The synchronous controller applies a voltage to the plurality of control electrodes, and, in a scanning period T of the image light, switches the optical state of the screen by the unit of the segmented region, between the visual state and the nonvisual state. The synchronous controller, in the period T, switches the optical state of a plurality of segmented regions 22 in synchronous with the scanning period of the image light, maintains the optical state of a projected region of the screen in the visual state by a voltage with two or more amplitudes.

First claim

The invention claimed is:

1. A display apparatus comprising:
a screen having an optical layer whose optical state is changed by applying a voltage and a plurality of control electrodes arranged side by side along the optical layer to apply the voltage to the optical layer;
a projector configured to project image light on the screen to display an image; and
a controller configured to apply the voltage to the plurality of control electrodes, to switch the optical state of the screen by the unit of each of segmented regions corresponding to the each of the control electrodes, between a predetermined visual state in which the image light is scattered and a nonvisual state which is different from the visual state, in a projection period of the image light,
wherein the controller switches the optical state of each of the plurality of segmented regions in the projection period of the image light, in synchronous with the projection of the image light by the projector, to control the optical state of the projected region of the image light in the visual state, and to maintains the optical state as the visual state with the voltage with two or more amplitudes.

2. The display apparatus according to claim 1 , wherein:
the projector scans the screen with the image light; and
the controller switches the applying voltage to the plurality of segmented regions in a scanning period of the image light in the scanning order, as each of the segmented regions both to be controlled in the visual state while being scanned in each of partial scanning period, and to be controlled in the nonvisual state in a period while not being scanned.

3. The display apparatus according to claim 2 , wherein:
the screen operates in a normal mode in which a transmittance of parallel rays is increased when the voltage is applied, and scatters the projected image light in the visual state; and
the controller:
applies the voltage to the control electrode corresponding to the segmented region controlled to be placed in the nonvisual state so as to control the voltage applied segmented region to be placed in a transmitting state; and
controls the applying voltage to the segmented region in the visual state in lower value than that in the nonvisual state so as to control the scanning segmented region with the image light in the scattering state and to scatter the image light.

4. The display apparatus according to claim 3 , wherein
the controller, in order to control the segmented region to be placed in the visual state,
increases the applying voltage after stopping the application of the voltage to the control electrode,
maintains the optical state of the segmented region in a predetermined scattering state which is in a lower degree than the maximum scattering state of the segmented region, and
stabilizes the scattering state of the segmented region during the partial scanning period for the scanning of the image light.

5. The display apparatus according to claim 2 , wherein:
the screen operates in a reverse mode in which an intensity of the scattering is increased by applying the voltage, and scatters the projected image light; and
the controller:
stops the application of the voltage to the control electrode corresponding to the segmented region to be placed in the nonvisual state so as to control the segmented region in the transparent and transmitting state; and
applies the voltage to the control electrode corresponding to the segmented region controlled to be placed in the visual state so as to control the segmented region to be scanned by the image light and to scatter the image light.

6. The display apparatus according to claim 5 , wherein
the controller, in order to control the segmented region to be placed in the visual state,
decreases the applying voltage after starting the application of the voltage to the control electrode,
maintains the optical state of the segmented region, and
stabilizes the scattering state of the segmented region during the partial scanning period for the scanning of the image light.

7. The display apparatus according to claim 6 , wherein
the controller, to control the segmented region in the visual state,
applies a first voltage to the control electrode, the voltage is higher than the voltage for controlling the segmented region in the maximum scattering state as the, and then
applies another voltage which is lower than the first voltage and is the voltage for the maximum scattering state.

8. The display apparatus according to claim 7 , wherein the controller, to control the segmented region in the visual state, changes the applying voltages from the first voltage at the timing when the scattering is maximized with the first voltage.

9. The display apparatus according to claim 1 , wherein the controller applies the voltage to the control electrode in an alternating voltage at a low frequency.

10. The display apparatus according to claim 1 , wherein the controller, in a plurality of projecting periods for the image light, switches the polarity of the applying voltage to the control electrodes by the unit of the projection period, so as to reduce the DC component of the applying voltage to the optical layer.

11. A method of driving a display apparatus configured to display an image formed by projected image light from a projector, on a screen having an optical layer whose optical state is changed in accordance with an applied voltage, the display apparatus including a controller that controls the optical state of the screen by:
applying the voltage to a plurality of control electrodes arranged side by side along the optical layer, to display the image formed by the image light on the screen which has the plurality of control electrodes;
switching the optical state of the screen between a predetermined visual state to scatter the image light and a nonvisual state which is different from the visual state, by the unit of the segmented regions in accordance with the control electrodes, in the projection period of the image light;
switching optical states of the plurality of segmented regions in the projection period of the image light, in synchronous with the projection of the image light by the projector, so as to control the optical state of the projected region of the screen to be placed in the visual state; and
maintaining the optical state in the visual state with the voltage with two or more amplitudes.

12. A screen apparatus for displaying comprising:
a screen configured to display an image formed by projecting image light, the screen having an optical layer whose optical state is changed by applying a voltage; and a plurality of control electrodes arranged side by side along the optical layer to apply the voltage to the optical layer; and
a controller configured to apply the voltage to the plurality of control electrodes, and to switch the optical state of each of segmented regions corresponding with the control electrodes, between a predetermined visual state in which the image light is scattered and a nonvisual state which is different from the visual state, wherein:
the controller, in the projection period of the light, switches the optical state of each of the plurality of segmented regions in synchronous with the projection of the image light onto the screen, so as to control the optical state of a projected region of the image light in the visual state, and
maintains the optical state as the visual state with the voltage with two or more amplitudes.

13. The display apparatus according to claim 2 , wherein the controller applies the voltage to the control electrode in an alternating voltage at a low frequency.

Assignees

• Pioneer Corp

Inventors

• Yoshioka Toshihiro

Classifications

• G03B21/10

  Projectors with built-in or built-on screen · CPC title

• H04N9/3129

  scanning a light beam on the display screen (scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161) · CPC title

• G03B21/62

  Translucent screens · CPC title

• G09G3/18

  using liquid crystals · CPC title

• G09G2320/041

  Temperature compensation · CPC title