Field sequential image display device
There has been room for improvement in terms of increasing the life of display elements which have occurrences of irreversible bright point defects and black point defects and shortened lives of display elements when DMDs, which are reflective display devices, are used in high temperature environments such as being installed in vehicles. In the present invention, a display control means displays a display image in display elements. An illumination control means drives various illumination means in each subframe into which a frame of the display image is temporally divided, by a field sequential system. The frame is provided with a display period in which the display image is displayed in the display elements by the display control means normally driving a plurality of pixels and the illumination control means driving the illumination means and a non-display period in which the display image is not displayed in the display elements by the display control means engaging in non-display period drive of the plurality of pixels and the illumination control means turning off the illumination means.
1. A field sequential image display apparatus, comprising:
a micromirror device, having a plurality of micromirrors configured to be ON/OFF controlled;
first light source, configured to emit light towards the micromirror device with a first color;
second light source, configured to emit light towards the micromirror device with a second color;
one or more controllers, configured to:
drive the first and second light sources using a field sequential method for each of sub-frames into which a frame of a display image is time divided; and
obtain display image data of the display image, and based on the display image data, control the incline of the micromirrors,
wherein the frame includes:
a display period in which the one or more controllers cause a normal drive of the plurality of micromirrors, and drive the first and second light sources, thereby causing the micromirror device to display the display image; and
a non-display period in which the one or more controllers cause a non-display period drive of the plurality of micromirrors, and turn off the first and second light sources, thereby not causing the micromirror device to display the display image,
wherein the one or more controllers are further configured to:
calculate an ON period and an OFF period of each micromirror in the display period, and
calculate an ON period and an OFF period of each micromirror in the non-display period, based on the calculation of the ON period and the OFF period of each micromirror in the display period, and
wherein the non-display period drive is based on the calculation of the ON period and the OFF period of each micromirror in the non-display period.
2. The field sequential image display apparatus according to claim 1 , wherein
the non-display period drive is such that each of the plurality of micromirrors is ON/OFF controlled in a predetermined cycle.
3. The field sequential image display apparatus according to claim 1 , wherein
the non-display period drive is such that each of the plurality of micromirrors is ON/OFF controlled so that an ON period and an OFF period of each of the plurality of micromirrors in the frame are approximately equal to each other.
4. The field sequential image display apparatus according to claim 1 , wherein
the non-display period drive is such that each of the plurality of micromirrors is ON/OFF controlled at an ON/OFF ratio wherein the ON/OFF ratio of each of the plurality of micromirrors in the display period is inverted.
5. The field sequential image display apparatus according to claim 1 , wherein
the non-display period drive is such that an ON/OFF control in the normal drive is inverted.
6. The field sequential image display apparatus according to claim 1 , further comprising:
a temperature detector that detects a temperature and outputs temperature data to the one or more controllers, wherein
when the temperature data are equal to or more than a first threshold, the display period and non-display period are provided in the frame.
7. The field sequential image display apparatus according to claim 1 , wherein
the one or more controllers are configured to gradually change a non-display proportion which is the proportion of the non-display period in the frame period, in accordance with the temperature data, based on control characteristics wherein the non-display proportion and temperature data are correlated in advance.
8. The field sequential image display apparatus according to claim 1 , wherein
the one or more controllers are configured to operate in a first regulation mode when the temperature data increase from equal to or less than the first threshold to equal to or more than the first threshold, and operate in a second regulation mode when the temperature data decrease from equal to or more than a second threshold higher in temperature than the first threshold to equal to or less than the second threshold, wherein
when operating in the first regulation mode, the one or more controllers do not cause the non-display proportion to decrease to less than the non-display proportion at the first threshold even when the temperature data are equal to or less than the first threshold, and
when operating in the second regulation mode, the one or more controllers do not cause the non-display proportion to increase to a value greater than the non-display proportion at the second threshold even when the temperature data are equal to or more than the second threshold.
9. The field sequential image display apparatus according to claim 8 , wherein
the one or more controllers operate with hysteresis control characteristics wherein a locus of control characteristics in the first regulation mode is different from a locus of control characteristics in the second regulation mode.
10. The field sequential image display apparatus according to claim 1 , wherein
the one or more controllers are configured to operate in an increase precedence mode when the temperature data increase from equal to or less than the first threshold to equal to or more than the first threshold, and operate in a decrease precedence mode when the temperature data decrease from the second threshold higher in temperature than the first threshold to equal to or less than the second threshold, wherein
when operating in the increase precedence mode, the one or more controllers cause the non-display proportion to increase based on the increase of the temperature data, and does not cause the non-display proportion to decrease even when the temperature data decrease, and
when operating in the decrease precedence mode, the one or more controllers cause the non-display proportion to decrease based on the decrease of the temperature data, and does not cause the non-display proportion to increase even when the temperature data increase.
11. The field sequential image display apparatus according to claim 1 , wherein
the OFF period of each of the plurality of micromirrors in the frame is longer than the ON period of each of the micromirrors.
12. The field sequential image display apparatus according to claim 1 , wherein
the non-display period is longer than the display period.