Imaging device equipped with automatic exposure control function

• US 20050057546A1
• Filed: 08/23/2004
• Published: 03/17/2005
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Shibutani, Atsushi
• Granted Patent: US 7,436,446 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 23/651 for reducing power consumption by affecting camera operations, e.g. sleep mode, hibernation mode or power off of selective parts of the camera
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene

Abstract

An imaging device comprises an organic EL monitor for displaying an image from an image pick-up device. A controller sets such initial values of at least one of a diaphragm amount, an exposure time, and a gain to values for causing control that the luminance level is increased toward a proper level when a power is turned on. Displaying of a through-image of only white is prevented.

Claims

1. An imaging device comprising:

an imaging element which outputs an image signal obtained by an imaging operation;

a self-luminous element which displays an image based on the image signal output from the imaging element; and

a limiting unit which limits brightness of the image displayed by the self-luminous element.

2. The imaging device according to claim 1, further comprising:

an exposure control unit which controls a luminance level of the image signal output from the imaging element such that the luminance level becomes a proper value, and wherein

the self-luminous element displays the image based on the image signal whose luminance level is controlled by the exposure control unit.

3. The imaging device according to claim 2, wherein the limiting unit limits the luminance level of the image signal controlled by the exposure control unit to a lower level when a power is turned on.

4. The imaging device according to claim 3, further comprising:

a setting unit to which an exposure control value is set, and wherein

the exposure control unit comprises a controller which controls the luminance level of the image signal output from the imaging element based on the exposure control value set in the setting unit, and setting, to the setting unit, an exposure control value which causes the luminance level of the image signal become the proper value.

5. The imaging device according to claim 4, wherein the limiting unit comprises a setter which sets an initial exposure control value to the setting unit such that the exposure control unit causes the luminance level of the image signal output from the imaging element always increase toward the proper value when a power is turned on.

6. The imaging device according to claim 4, wherein the limiting unit comprises a setter which sets an initial exposure control value to the setting unit which is lower than a medium value of a range of the exposure control value when a power is turned on.

7. The imaging device according to claim 4, further comprising:

a mode selection unit which selects a first control mode or a second control mode, and wherein

the limiting unit comprises a setter which sets a first initial exposure control value to the setting unit when the first control mode is selected at a time of power on, and a second initial exposure control value which is lower than the first initial exposure control value to the setting unit when the second control mode is selected at the time of power on.

8. The imaging device according to claim 7, wherein the first exposure control value is a medium value of a range of the exposure control value which can be set in the setting unit.

9. The imaging device according to claim 2, wherein the exposure control unit determines an exposure control value based on the luminance level of the image signal output from the imaging element, and controls the luminance level of the image signal based on the determined exposure control value.

10. The imaging device according to claim 9, wherein:

the imaging element continuously outputs a plurality of image signals obtained by a plurality of continuous imaging operations;

the exposure control unit determines an exposure control value based on a luminance level of a current image signal output from the imaging element and controls a luminance level of a next image signal based on the determined exposure control value.

11. The imaging device according to claim 10, wherein:

the exposure control unit changes a current exposure control value by a predetermined value based on the luminance level of the current image signal output from the imaging element, and controls the luminance level of the next image signal based on the changed exposure control value.

12. The imaging device according to claim 2, wherein the exposure control unit controls the luminance level of the image signal by controlling at least one of a diaphragm amount of the imaging element, an exposure time of the imaging element, and an amplification factor of the image signal so that the luminance level becomes the proper value.

13. The imaging device according to claim 3, wherein:

the exposure control unit controls the luminance level of the image signal by controlling at least one of a diaphragm amount of the imaging element, an exposure time of the imaging element, and an amplification factor of the image signal so that the luminance level may be a proper value; and

the limiting unit controls the luminance level of the image signal to be low by controlling at least one of the diaphragm amount of the imaging element, the exposure time thereof, and the amplification factor of the image signal.

14. The imaging device according to claim 2, wherein the limiting unit limits the brightness of the image displayed by the self-luminous element for a certain period immediately after a power is turned on.

15. The imaging device according to claim 14, wherein the certain period is a predetermined period.

16. The imaging device according to claim 14, wherein the certain period is a period until the luminance level of the image signal output from the imaging element becomes lower than a predetermined level.

17. The imaging device according to claim 14, wherein the limiting unit controls, for the certain period immediately after the power is turned on, the brightness of the image displayed by the self-luminous element to be lower than a brightness of an image displayed by the self-luminous element after a passage of the certain period.

18. The imaging device according to claim 1, wherein the limiting unit limits the brightness of the image displayed by the self-luminous element to be lower than a predetermined brightness.

19. The imaging device according to claim 18, wherein the limiting unit controls the brightness of the image displayed by the self-luminous element to be zero.

20. The imaging device according to claim 1, wherein the limiting unit controls the brightness of the image displayed by the self-luminous element to be lower by a predetermined percentage.

21. The imaging device according to claim 1, wherein the limiting unit limits the brightness of the image displayed by the self-luminous element based on the luminance level of the image signal output from the imaging element.

22. The imaging device according to claim 1, further comprising:

a determination unit which determines whether the luminance level of the image signal output from the imaging element is higher than a predetermined level or not, and wherein

the limiting unit limits the brightness of the image displayed by the self-luminous element when the determination unit determines that the luminance level of the image signal is higher than the predetermined level.

23. The imaging device according to claim 1, wherein the limiting unit controls the brightness of the image displayed by the self-luminous element by controlling emission luminance of the self-luminous element itself.

24. The imaging device according to claim 1, further comprising:

an adjusting unit which adjusts the luminance level of the image signal output from the imaging element, and wherein

the self-luminous element displays the image whose luminance level is adjusted by the adjusting unit; and

the limiting unit controls the brightness of the image displayed by the self-luminous element by controlling the adjustment of the luminance level by the adjusting unit.

25. The imaging device according to claim 1, further comprising:

a mode setting unit which sets a predetermined control mode, and wherein

the limiting unit limits the brightness of the image displayed by the self-luminous element when the predetermined operation mode is set by the mode setting unit.

26. An imaging device comprising:

means for outputting an image signal obtained by an imaging operation;

a self-luminous element which displays an image based on the image signal; and

means for limiting brightness of the image displayed by the self-luminous element.

27. An imaging method comprising:

outputting an image signal obtained by an imaging operation;

causing a self-luminous element to display an image based on the image signal; and

limiting brightness of the image displayed by the self-luminous element.

28. An imaging control program which causes a computer of an imaging device to execute:

processing of outputting an image signal obtained by an imaging operation;

processing of causing a self-luminous element to display an image based on the image signal; and

processing of limiting brightness of the image displayed by the self-luminous element.