JP2000010068A - Electronic equipment provided with reflection type liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce power consumption and also to automatically provide an optimum display definition a user does not perform any complicated adjusting operation in an electronic equipment provided with reflection type liquid crystal display. SOLUTION: This equipment is provided with a light source 22 illuminating the display screen of a reflection type liquid crystal display(LCD) 20, and performs the ON/OFF control of the light source 22 and also automatically controls the illuminating light quantity of the source 22 based on the brightness of surroundings detected by means (for example, a CCD 14, a strobe light control sensor 34, a photosensor 40) for detecting an outer light quantity. Moreover, when the light source is not used, the device suppresses wasteful power consumption by turning off the LCD 20 automatically under a situation where the surroundings is so dark that the screen of the display can not be identified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic apparatus such as an electronic camera such as a digital camera or a portable information terminal having a reflective liquid crystal display as a display unit.

[0002]

2. Description of the Related Art Heretofore, a transmission type liquid crystal display has been used as a monitor screen of a digital camera. But,
The transmissive liquid crystal display has a drawback that power must be constantly supplied to the backlight and power consumption is large.
On the other hand, the electronic camera disclosed in Japanese Patent Application Laid-Open No. 8-242398 has a photometric device for measuring the brightness of the subject, and automatically adjusts the brightness of the backlight according to the brightness of the subject, thereby saving power. Also, the monitor visibility is improved.

[0003]

However, as disclosed in the above publication, even if the brightness of the backlight is adjusted, the effect of contributing to power saving is small. However, there is a limit in using a transmission type liquid crystal display. Therefore, adoption of a reflective liquid crystal display that does not require a backlight is being considered instead of the transmissive liquid crystal display. The reflective liquid crystal display has the advantage of low power consumption, but has the disadvantage that the screen is difficult to see in dark places. Therefore, in order to use the reflection type liquid crystal display, it is necessary to take specific measures such as illuminating the liquid crystal display surface with auxiliary light in an environment where the surroundings are dark.

The present invention has been made in view of such circumstances, and greatly reduces power consumption, and automatically sets an optimal display state without a complicated adjustment operation or the like by a user. It is an object of the present invention to provide an electronic device having a reflective liquid crystal display that can be obtained.

[0005]

According to one aspect of the present invention, there is provided an electronic apparatus having a reflective liquid crystal display as a display unit, the illumination unit illuminating a display screen of the reflective liquid crystal display. Detection means for detecting the brightness of the surroundings; and control means for turning on / off the lighting means or adjusting the amount of illumination light according to the brightness detected by the detection means. It is characterized by.

According to the present invention, the brightness of the surroundings is detected by the detecting means, and when the surroundings are sufficiently bright, the illuminating means is turned off. Illuminate the display screen to make it easier to see.
In addition to simply controlling ON / OFF of the illuminating means, the illuminating light amount of the illuminating means may be appropriately adjusted according to the brightness detected by the detecting means to obtain a more easily viewable screen display. As a result, power saving can be achieved, and optimal display quality can be automatically provided.

According to a second aspect of the present invention, in an electronic apparatus having a reflective liquid crystal display as a display unit, a detecting means for detecting ambient brightness, and the reflective liquid crystal in accordance with the brightness detected by the detecting means. ON / OFF of display,
Or control means for adjusting the contrast of the display screen;
Is provided. The present invention has been made in view of the fact that a reflection type liquid crystal display cannot be used in a dark place without using illumination means. That is, the detecting means detects the brightness of the surroundings, and when the surroundings are sufficiently bright, the reflective liquid crystal display is turned on. On the other hand, when the surroundings are dark and the display screen cannot be identified, the reflective liquid crystal display is eventually used. Since it cannot be performed, this is turned off to suppress unnecessary power consumption.

Also, depending on the degree of ambient brightness, the display screen may be sufficiently visible by adjusting the contrast. Therefore, the contrast of the reflective liquid crystal display is appropriately optimized and controlled in accordance with the brightness detected by the detecting means. It is also effective. According to the first and second aspects of the present invention, as described in the third or fourth aspect, the subject light incident through the lens is photoelectrically converted to an image signal indicating the subject image. The present invention can be applied to an electronic camera having an image sensor. In this case, claim 5
Or a strobe light control sensor attached to the electronic camera, a photometric sensor for exposure control,
Alternatively, it is preferable that an AE photometer comprising an image sensor and a signal processing circuit is also used as the detector.

According to a seventh aspect of the present invention, in the electronic camera according to the third or fourth aspect, further, an optical finder and a second detection for detecting whether a photographer is looking into the optical finder. Means for turning on the reflective liquid crystal display when the second detecting means detects that the photographer is looking into the optical viewfinder.
And F second control means.

The detection means detects whether or not the photographer is looking into the optical viewfinder. When the photographer is looking into the optical viewfinder, the power supply to the reflection type liquid crystal display is cut off, so that there is no waste. Power consumption can be suppressed. In addition, in particular, as in claim 8, the second
It is preferable that a light detection sensor is used as the detection means, and that this is also used as a detection means for detecting ambient brightness. The second control means may be integrated with the control means in the electronic camera according to the third or fourth aspect.

According to a ninth aspect of the present invention, in the electronic camera according to the third or fourth aspect, a third detecting means for detecting a backlight based on a luminance distribution of a subject, and the third detecting means. And third control means for adjusting the contrast of the display screen of the reflective liquid crystal display when it is detected that the backlight is detected. According to the aspect in which such a configuration is added, it is possible to automatically provide a more optimal display state according to the use situation without forcing the user (user) to perform a complicated adjustment operation or the like. Note that the third control means is a third or fourth aspect.
The electronic camera according to the present invention may be integrated with the control means.

[0012] As described in claim 10, claim 3.
In addition to the configuration of the electronic camera according to the third aspect, a third detection unit that detects backlight based on the luminance distribution of the subject, and the lighting unit is turned on when the third detection unit detects that backlight is detected. And a third control unit for performing adjustment for increasing the light amount of the illumination unit.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electronic apparatus having a reflective liquid crystal display according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an electronic camera according to an embodiment of the present invention. As shown in FIG. 1, the electronic camera 10 mainly includes a photographing lens 12, a solid-state imaging device (CCD) 14, a signal processing circuit 16, a microcomputer (microcomputer) 18, a color reflective liquid crystal display (LCD) 20, And a light source 22 for providing auxiliary light for illuminating the display screen of the LCD 20.

The image light representing the subject is formed on the light receiving surface of the CCD 14 via the taking lens 12. The CCD 14 converts the image light formed on the light receiving surface into signal charges of an amount corresponding to the light amount. The signal charge thus accumulated is C
The data is sequentially transferred based on a drive pulse applied from a CD drive circuit (not shown), and is read as a voltage signal (image signal) corresponding to the signal charge.

The image signal read from the CCD 14 is applied to a signal processing circuit 16, where color separation, gain adjustment, gamma correction, A / D conversion, and other signal processing are performed. After decoding the image data generated by the signal processing circuit 16, the image data is supplied to the LCD 20 via the liquid crystal control circuit 24. Thus, the image captured by the CCD 14 is displayed on the LCD 2
Displayed as 0.

Before receiving a photographing start signal issued from a release switch or the like of the operation unit 26, a preview image (moving image or intermittent image monitored before actual photographing) is displayed on the LCD 20.
Is displayed, and upon receiving the photographing start signal, the image signal read from the CCD 14 undergoes a predetermined process in the signal processing circuit 16 and then is displayed on the LCD 20 as a still image. Simultaneously with this or after the display of the still image is completed, the image data is subjected to compression processing as necessary, and is recorded on a recording medium such as the memory card 28. Note that the recording medium may be in various forms such as a smart media and an IC card. The recording medium is not limited to a detachable external recording medium but may be a built-in memory. In addition, the shooting start signal may be applied from outside the electronic camera 10 such as a remote controller or an externally connected device. When the above-described recording processing is completed, the freeze of the screen is released and the display returns to the moving image or the intermittent image display.

The image data stored in the memory card 28 can be read out under the control of the microcomputer 18, and the read out image data is subjected to decompression processing as required, and then passed through the liquid crystal control circuit 24. Is output to the LCD 20. Thus, the reproduced image is displayed on the LCD 20. Although a detailed structure of the LCD 20 is not shown, basically, liquid crystal is sealed between a pair of transparent plates having display electrodes, and a film retardation plate and a polarizing plate are arranged outside the liquid crystal.
It has a structure in which a reflector is provided on the surface opposite to the incident light side.
Then, display is performed by reflecting the light beam using ambient light. The LCD 20 is controlled by the microcomputer 18 via the liquid crystal control circuit 24, and the contrast is automatically adjusted according to the surrounding brightness and the brightness distribution of the subject, as will be described in detail later.
When the surroundings are dark, the light source 22 is turned on to turn on the LCD.
20 display screen is illuminated. The light source 22 includes a fluorescent tube, L
Various forms such as an ED and a white light can be used.

The light source 22 is controlled by the microcomputer 18 via a dimming control circuit 30, and is automatically turned on / off according to the surrounding brightness, and also adjusts the brightness of the light source (the amount of irradiation light). Is performed. On the other hand, an illumination switch 32 for manual operation is also provided, and when the user operates this switch, the microcomputer 18 gives priority to the instruction of the illumination switch 32 over the automatic light source control processing and turns on the light source 22 according to the switch operation. / OFF or adjust. Thereby, the user can turn on / off / dim the light source 22 as needed.

The microcomputer 18 performs overall control of each circuit based on a switch operation from an operation unit 26 such as a power switch and a release switch. The microcomputer 18 controls the driving of the CCD 14, the read / write of the memory card 28, and a predetermined operation. Various calculations such as an exposure value and a focus position are performed according to an algorithm, and control such as automatic exposure control, auto focus, auto strobe, and auto white balance is performed.

That is, the microcomputer 18 controls the signal processing circuit 16
The brightness of the subject (subject brightness) and the brightness distribution are obtained based on the integrated average value of the image signals output from the CPU, the current aperture value, and the electronic shutter speed. Then, the aperture value and the charge storage time (electronic shutter speed) of the CCD 14 are determined based on the obtained brightness of the subject, the aperture mechanism is controlled based on the determined aperture value, and the CCD is controlled based on the electronic shutter speed. Control the drive circuit.

As described above, the brightness of the object, that is, the brightness of the surroundings is detected by processing the output signal from the CCD 14 by the signal processing circuit 16, and the light source 22 and the LCD 20 are controlled based on the detection result. . The means for detecting the surrounding brightness is not limited to this, and a dedicated photometric element may be provided, or a photometric element that is also used as an exposure meter may be used. Further, the strobe light control sensor 34 and the light detection sensor 38 of the optical viewfinder 38 may be used in common, and any form may be used as long as it can detect the surrounding brightness (external light amount).

The autofocus means can take various forms. For example, a focus evaluation value indicating the sharpness of a subject image is calculated from an image signal, and the focus position is calculated based on the focus evaluation value. . Then, the photographing lens 12 is controlled via a focus drive circuit (not shown) according to the calculated focus position, and the focus position is set. In addition, a known distance measuring unit such as an AF sensor may be used.

The microcomputer 18 controls the strobe 36 in accordance with the ambient brightness detected by the strobe light sensor 34. An optical detection sensor 40 is provided near the eyepiece (viewing window) of the optical viewfinder 38. The light detection sensor 40 is means for detecting whether or not the photographer has looked into the optical viewfinder 38, and for example, a light receiving sensor is used. When the photographer's face approaches the viewfinder eyepiece, the photographer takes advantage of the fact that the area around the eyepiece is shaded by the photographer and the amount of light received by the sensor changes.
8 is detected.

In addition, when the photographer's face approaches the viewfinder eyepiece, the light emitted from the light emitting unit is reflected by the photographer's face by using the light detection sensor 40 including a light emitting unit and a light receiving unit. A configuration that detects whether or not the photographer is looking through the optical viewfinder 38 based on a change in the amount of light incident on the light receiving unit may be employed. The detection signal of the light detection sensor 40 is notified to the microcomputer 18, and the microcomputer 18 forcibly turns the LCD 20 and the light source 22 through the liquid crystal control circuit 24 and the dimming circuit 30 while the photographer is looking into the optical viewfinder 38.
FF control is performed.

Next, the operation of the electronic camera configured as described above will be described. FIG. 2 is a flowchart showing a control flow in the microcomputer. A sensor detection process for detecting the surrounding brightness is performed using the CCD 14 and the signal processing circuit 16 (step S110), and the detected brightness is higher than a predetermined brightness (a reference value of a boundary where the light source 22 is turned on). It is determined whether or not it is bright (step S11)
2). Ambient light is sufficiently bright, LCD2
If it is determined that 0 can be sufficiently identified, the LCD 20
Since there is no need to supply auxiliary light to the light source 22, the light source 22 is turned off (step S114).

On the other hand, in the judgment of step S112,
If it is determined that the surroundings are dark, the light source 22 is turned on so as to provide the LCD 20 with the auxiliary light (Step S).
116). Then, the luminance of the auxiliary light is adjusted via the dimming control circuit 30 according to the degree of the surrounding brightness (step S118). The brightness of the auxiliary light is increased as the surroundings are darker, and the brightness of the auxiliary light is decreased as the surrounding becomes darker. In this manner, the display screen of the LCD 22 is illuminated by the light source 22 so that the display can be easily viewed.

The above steps S110 to S11
8 is periodically executed in a fixed cycle (step S120). Alternatively, when power is turned on, step S11
0 to step S118, and thereafter, when any switch operation is performed, such as half-pressing the release switch or instructing playback frame advance, steps S110 to S118.
The processing of 118 may be executed.

As described above, according to the electronic camera 10 of this embodiment, the brightness of the surroundings is detected, the light source 22 is automatically turned on only when the brightness is low, and the brightness is appropriately adjusted according to the degree of brightness. Since it is adjusted to the value, it is possible to achieve power saving, and without forcing the user to perform a complicated adjustment operation,
It is possible to provide an optimum display quality according to the situation.

Further, the photometric means performs divided photometry to grasp the luminance distribution of the subject, compares the luminance of the main subject with the luminance of its surroundings, detects backlight, and controls the lighting of the light source 22 when the backlight is detected. Alternatively, control for increasing the amount of the illumination light may be performed. Further, in the case of backlight photography, it is preferable to perform control for automatically increasing the contrast of the LCD 20. The automatic contrast adjustment is preferably performed not only in the backlight but also in a case where a part of the screen becomes extremely bright like a spot light.

In the above embodiment, the LCD 2
Although the electronic camera provided with the light source 22 for providing the auxiliary light to 0 has been described as an example, a mode in which the light source 22 is not used is also conceivable.
In this case, as shown in FIG. 3, sensor detection processing for detecting the surrounding brightness is performed using the CCD 14 and the signal processing circuit 16 (step S130), and the detected brightness is set to the predetermined brightness (LCD 20). It is determined whether the screen is brighter than a reference value (a boundary value at which the screen cannot be identified) (step S132). Ambient light is sufficiently bright, and L
If it is determined that CD20 can be sufficiently identified, LC
D20 is turned on (step S134), and the contrast is adjusted according to the detection of backlight or spot light (step S136).

On the other hand, in the judgment of step S112,
If it is determined that the surroundings are dark enough that the display of the LCD 20 cannot be identified, the display cannot be recognized even if the LCD 20 is energized, so that the energization of the LCD 20 is cut off (step S138). The processing of the above-described steps S130 to S138 is periodically executed in a fixed cycle (step S140). Alternatively, the processing of steps S130 to S138 is performed when the power is turned on, and then the processing of steps S130 to S138 is performed when any switch operation is performed, such as pressing the release switch halfway or instructing playback frame advance. Is also good.

As described above, according to the electronic camera which performs the control shown in FIG. 3, since the surrounding brightness is detected and the LCD 20 is turned off when it is dark, useless power consumption can be suppressed. In particular, in the shooting mode, L
It is preferable that when the CD 20 is turned off, the driving of the CCD 14 is also stopped to further reduce power consumption. In this case, the CCD 14 may be restarted by half-pressing the release switch, or a sequence may be employed in which the optical detection sensor 40 detects this when looking into the optical viewfinder 38 and restarts the driving of the CCD 14. Shooting can be performed even in a dark environment.

In the above embodiment, an electronic camera has been described as an example. However, the present invention can be widely applied not only to an electronic camera but also to a portable television receiver, a videophone, a portable information terminal, and other electronic devices. it can. In particular, application to a portable electronic device using a battery is effective.

[0034]

As described above, according to the electronic apparatus provided with the reflective liquid crystal display according to the present invention, the brightness of the surroundings is detected, the lighting means is turned off when the surroundings are bright, and the surroundings are darkened. Since only the lighting means is turned on, power saving can be achieved. Therefore, the battery can be used for a long time. In addition, since the light amount of the lighting means is automatically adjusted according to the degree of the surrounding brightness, the photographer does not need to adjust the illuminating light according to the surrounding brightness, and the convenience is improved. .

According to the electronic apparatus having the reflective liquid crystal display according to the second aspect, the reflective liquid crystal display is turned off in a situation where the surroundings are dark enough that the display screen cannot be identified. Consumption can be reduced. Further, since the contrast is automatically adjusted according to the degree of the surrounding brightness and the luminance distribution of the subject, a complicated adjustment operation is not required.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic camera according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a light source control method of the electronic camera shown in FIG.

FIG. 3 is a flowchart showing a control method of an electronic camera according to another embodiment without lighting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Electronic camera (electronic equipment) 14 ... Solid-state image sensor (CCD) 16 ... Signal processing circuit 18 ... Microcomputer (control means) 20 ... Reflective liquid crystal display 22 ... Light source (illumination means) 24 ... Liquid crystal control circuit (control means) 30) dimming control circuit (control means) 34 ... strobe dimming sensor 40 ... light detecting sensor (second detecting means)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 5/66 102 H04N 5/66 102B 5G435 F term (reference) 2H018 AA31 AA32 2H093 NA06 NC07 NC42 NC49 NC50 NC55 ND02 ND05 ND17 ND39 NE06 5C006 AA01 AA02 AF46 AF51 AF52 AF53 AF54 AF63 AF69 AF81 BB28 BB29 BF15 BF38 EA01 EC01 EC08 FA47 FA54 5C022 AA12 AB11 AB15 AB67 AC02 AC03 AC52 AC69 5C058 AA06 BA08 BA26 5G435 AA00 BB12 BB16 EE14 BB21

Claims (10)

[Claims] 1. An electronic device having a reflective liquid crystal display as a display unit, an illuminating means for illuminating a display screen of the reflective liquid crystal display, a detecting means for detecting ambient brightness, and a brightness detected by the detecting means. An electronic device comprising a reflective liquid crystal display, comprising: a control unit for turning on / off the illumination unit or adjusting the amount of illumination light in accordance with the above. 2. An electronic apparatus having a reflective liquid crystal display as a display unit, comprising: detecting means for detecting ambient brightness; and turning on / off the reflective liquid crystal display in accordance with the brightness detected by the detecting means. Or a control means for adjusting the contrast of a display screen, and an electronic device provided with a reflective liquid crystal display. 3. An image sensor for photoelectrically converting subject light incident through a lens to convert the light into an image signal indicating a subject image; a reflective liquid crystal display used as display means; and a display screen of the reflective liquid crystal display. Lighting means for illuminating the light; detecting means for detecting the brightness of the surroundings; control means for turning on / off the lighting means or adjusting the amount of illumination light in accordance with the brightness detected by the detecting means; An electronic camera provided with a reflective liquid crystal display, comprising: 4. An imaging device for photoelectrically converting subject light incident through a lens to convert the light into an image signal indicating a subject image, a reflective liquid crystal display used as a display unit, and a detection device for detecting ambient brightness. And a control means for turning on / off the reflective liquid crystal display or adjusting the contrast of the display screen in accordance with the brightness detected by the detection means. Electronic camera. 5. An electronic camera comprising a reflective liquid crystal display according to claim 3, wherein a strobe light control sensor is used as said detecting means. 6. The electronic camera according to claim 3, wherein said detection means comprises said image sensor and a signal processing circuit. 7. An optical viewfinder; second detecting means for detecting whether or not a photographer is looking into the optical viewfinder; and a photographer looking into the optical viewfinder by the second detecting means. 5. An electronic camera equipped with a reflective liquid crystal display according to claim 3, further comprising second control means for turning off said reflective liquid crystal display when detected. 8. An electronic camera equipped with a reflective liquid crystal display according to claim 3, wherein said second detection means comprises a light detection sensor, and is also used as said first detection means. 9. A third detecting means for detecting a backlight based on a luminance distribution of a subject, and a contrast of a display screen of the reflective liquid crystal display when the third detecting means detects the backlight. Make adjustments to increase the third
5. An electronic camera comprising a reflective liquid crystal display according to claim 3, further comprising: a control unit. 10. A third detecting means for detecting a backlight based on a luminance distribution of a subject, and lighting the lighting means when the third detecting means detects the backlight, or Third adjustment to increase the light intensity of the means
4. An electronic camera equipped with a reflective liquid crystal display according to claim 3, further comprising: control means.