Light control apparatus for an image sensing optical device
An apparatus for controlling the quantity of light incident on an image sensor by controlling size or shape of a diaphragm and also by adjusting light transmittance of the diaphragm is provided. The light control apparatus is disposed on the light path of the image sensing device and controls a quantity of light incident on the image sensor. The light control apparatus includes a Guest-Host LCD panel applied no polarizing film and a control unit for reducing the time to take multi-frame detection by driving voltages which are applied to respective pixels of the Guest-Host LCD panel, to be increased at least when taking multiple frames in series. The Guest-Host LCD panel has a plurality of pixels forming closed curves or boundaries on a plane, which are electrically driven individually. Also, the pixels have uniform light transmittance throughout the entire azimuth of the closed curves or boundaries with an origin.
1. A light control apparatus for an image sensing device, disposed on a light path to an image sensor, for adjusting an amount of light incident on the image sensor,
the light control apparatus comprising:
a Guest-Host LCD panel applied no polarizing film; and
a control unit includes a multi-frame detection mode, wherein the control unit is configured to detect a succession of multiple images of the same scene and select a predetermined best image from among the multiple detected images, and the control unit is configured to gradually increase an average voltage applied to each of the respective pixels of the guest host LCD panel during an image detection period in order to reduce a time for detecting the succession of the multiple images,
wherein:
the Guest-Host LCD panel has a plurality of pixels forming closed curves or boundaries on a plane, which are electrically driven individually,
the pixels have uniform light transmittance throughout the entire azimuth of the closed curves or boundaries with an origin.
2. The apparatus of claim 1 , wherein the closed curve has a shape of a circle, an ellipse, or a regular polygon.
3. The apparatus of claim 2 , wherein the regular polygon has rounded edges.
4. The apparatus of claim 1 , wherein the Guest-Host LCD panel has the maximum visible light transmittance higher than 50%.
5. The apparatus of claim 1 , wherein the Guest-Host LCD panel includes a pleochroic dye, and the Guest-Host LCD panel's mode is either Normally White or Normally Black.
6. The apparatus of claim 1 , wherein the Guest-Host LCD panel has varied light transmittance according to the average applied voltage to the panel.
7. The apparatus of claim 1 , further comprising,
an IRIS system, disposed on the light path, for controlling an amount of light incident on the image sensor along the central axis.
8. The apparatus of claim 7 , wherein the closed curve has an area smaller than an extent of the minimum aperture of the IRIS system.
9. The apparatus of claim 1 , wherein the Guest-Host LCD panel is located in the light path of a lens unit.
10. The apparatus of claim 1 , wherein after taking the multiple frames, the control unit decreases an averaged voltage applied to the pixels to go back to an initial state.
11. The apparatus of claim 1 , wherein the Guest-Host LCD panel has multiple pixel areas that are each continuously overlapped on a same plane radially with an origin,
the respective pixel areas each having a plurality of pixels forming closed curves or boundaries on a plane, and being electrically driven, individually; and
the pixels having uniform light transmittance throughout an entire azimuth of the origin.