JP2000241800A - Display device of camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate a proper display irrespective of external light and color temperature of an object by providing this display device with a light quantity adjusting means for adjusting brightness of backlight based on the photometric element placed at a position where the external light and backlight are measured at the same time and an output of the photometric element. SOLUTION: A brightness sensor 17 is arranged at a position where light αfrom backlight 13 and external light β through a lighting window 14 can be measured at the same time, and a color sensor 18 is arranged at a position where only the eternal light β through the lighting window 14 can be measured, respectively. And, on the view finder side of this camera, an illuminance signal measured by a brightness sensor 17 and color temperature signal measured by the color sensor 18 are led to a illuminance control part through an internal sensor. The illuminance control part controls a light quantity of the backlight 13 via an inverter. In this case, the brightness sensor 17 measures a synthesized quantity of the light of the backlight and the external light 13 through the lighting window 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for a camera such as an electronic camera, and more particularly, to a display device using external light in addition to a backlight as back light for a liquid crystal display panel.

[0002]

2. Description of the Related Art Some electronic cameras have a liquid crystal display panel for displaying an image of a subject or a recorded image. This liquid crystal display panel illuminates by taking in external light from a backlight or a lighting window provided inside.

[0003] Japanese Patent Application Laid-Open No. 7-177398 discloses a backlight that selectively uses a backlight or external light based on the brightness of external light as the backside illumination light of a liquid crystal display panel of a viewfinder. It is trying to control the amount of light and the amount of opening and closing of the external light intake window. The brightness of the external light is measured by an external light sensor directed to the subject.

On the other hand, in the technique described in Japanese Patent Application Laid-Open No. 7-199848, when external light is used as a light source, a video signal is converted to an external light in order to prevent the white balance of an image from being destroyed by the color of the external light. The correction is made according to the color temperature of the image, or an attempt is made to pass through an optical filter.

[0005]

The above-described conventional camera display device has the following problems. That is, in the method described in JP-A-7-177398, when the brightness of the backlight is controlled by the brightness of the subject as external light, when there is a difference between the optical environment of the subject and the lighting window, appropriate control is performed. Is not done. For example, assuming that the subject is bright but the area around the camera is dark, or conversely, the subject is dark but the area around the camera is bright, controlling the brightness of the backlight using the brightness information obtained from the object. It doesn't make sense to do it.

Further, external light to be used in combination with a backlight does not always provide white light. At this time, an attempt is made to obtain an image with a good white balance.
In 1998848, the R, G, and B gains of a video signal are corrected based on the color temperature of external light. However, the color temperature of external light has various characteristics depending on the type of external light, and this color temperature is estimated by measuring a specific wavelength, but the actual wavelength characteristics do not always match. Therefore, it is actually very difficult to accurately correct the color temperature by the gain correction of the video signal.

Further, when illuminating the liquid crystal display panel with external light, an optical filter having a predetermined spectral transmittance characteristic is provided to correct the energy ratio of R, G and B of the external light. However, in this case, it is not possible to cope with a case where the color temperature of the external light changes variously. Providing a filter leads to an increase in size and cost of the device.

Accordingly, an object of the present invention is to provide a camera display device capable of easily performing appropriate display regardless of the brightness and color temperature of an object or external light.

[0009]

In order to solve the above-mentioned problems and to achieve the object, the invention according to the first aspect is directed to a liquid crystal display panel using at least one of external light taken in from a backlight or a daylighting unit. In a display device of a camera capable of illuminating, a photometric element arranged at a position capable of simultaneously measuring external light taken in from the lighting section and light of the backlight, and an output of the photometric element. Light amount adjusting means for adjusting the brightness of the backlight based on the light amount.

According to a second aspect of the present invention, there is provided a camera display device having a display unit capable of illuminating a liquid crystal display panel with at least one of a backlight and external light taken in from a daylighting unit. A colorimetric unit for measuring information on the color temperature of the external light and a light amount adjusting unit for adjusting the brightness of the backlight based on an output of the colorimetric unit are provided.

According to a third aspect of the present invention, in the second aspect of the invention, when it is determined that the color temperature of the external light is different from the normal color temperature as a result of the colorimetry by the colorimeter, The liquid crystal display panel is illuminated by the backlight.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the image displayed on the liquid crystal display panel is an image whose white balance has been adjusted.

[0013]

FIG. 1 is a sectional view showing a main part of an electronic camera 1 according to an embodiment of the present invention. Electronic camera 1
The camera body 2 includes a camera body 2 mainly having an image capturing function, and a viewfinder 3 provided in the camera body 2 to monitor a captured image.

The viewfinder 3 includes a housing 10 and
And a lens 11 attached to the housing 10. Further, inside the housing 10, a liquid crystal display panel 12, a backlight 13, a lighting window 14, a light guide prism 15, a light collector 16, a brightness sensor 17 for simultaneously measuring the brightness of the external light and the backlight, A color sensor 18 for measuring a color temperature and a lighting window cover 19 are provided.

The surface of the liquid crystal display panel 12 is arranged at a position that can be seen through the lens 11. Further, a backlight 13 that illuminates the liquid crystal display panel 12 is disposed at a position facing the back surface side of the liquid crystal display panel 12. The light guiding prism 1 is provided between the liquid crystal display panel 12 and the backlight 13.
5 and a light collector 16 are provided, and the external light β from the lighting window 14 at the upper part in FIG. 1 and the light from the backlight 13 are combined and applied to the back surface of the liquid crystal display panel 12. . The light guide prism 15 has an inclined cross section, and transmits light α from the backlight 13 in a straight line,
It has a function to bend the external light β from the lighting window 14 on the reflection surface and guide it to the light collector 16. The light collector 16 is a light guide prism 15
Is scattered evenly on the back surface of the liquid crystal display panel 12.

The brightness sensor 17 is at a position where the light α from the backlight 13 and the external light β from the lighting window 14 can be measured at the same time, and the color sensor 18 is at a position where only the external light β from the lighting window 14 can be measured. Are provided respectively.

A daylighting window cover 19 is attached to the daylighting window 14 so that it can be automatically or manually opened and closed.

FIG. 2 shows a liquid crystal display panel 12 of the electronic camera 1.
FIG. 3 is a block diagram showing a control system of FIG.

The camera body 2 includes a lens group 21 directed to a subject, a diaphragm device 22 for adjusting the amount of light incident through the lens group 21, and a light component incident through the diaphragm device 22. And a camera signal processing unit 24 and a video signal processing unit 25, each of which processes the electric signal and converts it into a video signal. A subject light sensor 26 for measuring the light of the subject
And an aperture control unit 27 that adjusts the degree of opening of the aperture device 22 based on the output of the subject optical sensor 26.

The viewfinder 3 includes an RGB decoder 28 for color-separating the video signal from the video signal processing unit 25. The backlight 13 illuminates the liquid crystal display panel 12, an inverter 31 for driving the backlight 13, an illuminance control unit 32 for adjusting the output of the inverter 31, the brightness sensor 17 and the color sensor 18 described above. And an internal sensor 33 that sends a signal to the illuminance control unit 32 based on the output of.

In the electronic camera 1 configured as described above,
The brightness and white balance of the liquid crystal display panel 12 are adjusted as follows.

An optical image of a subject incident through a lens group 21 of the camera body 2 is converted into an electric signal by a CCD image pickup device 23 through a diaphragm device 22. This electric signal is subjected to signal processing by a camera signal processing unit 24 and a video signal processing unit 25, respectively. The video signal output of the video signal processing unit 25 is guided to the viewfinder 3 side, is subjected to color separation by the RGB decoder 28, and displays a color video on the liquid crystal display panel 12. The brightness of the subject is measured by the subject optical sensor 26, and the output thereof is automatically adjusted by the aperture control unit 27 so as to obtain an appropriate aperture amount.

On the other hand, on the viewfinder 3 side, the illuminance signal measured by the brightness sensor 17 and the color sensor 18
The color temperature signal measured by the above is led to the illuminance control unit 32 through the internal sensor 33. The illuminance control unit 32 controls the amount of light of the backlight 13 via the inverter 31. The brightness sensor 17 measures the combined light amount of the light of the backlight 13 and the external light from the lighting window 14.

The brightness sensor 17, the internal sensor 33, the illuminance control unit 32, the inverter 31, and the backlight 13 form a closed loop.
Automatically adjust the illuminance. That is, when the external light β is strong, the illuminance of the backlight 13 is reduced, and when the external light β is weak, the illuminance of the backlight 13 is increased.
A uniform and appropriate brightness is always obtained. As a result, the power consumption of the backlight 13 is properly used, and the life of the fluorescent tube serving as the light source of the backlight 13 can be extended.

Although white light with white balance is obtained from the backlight 13, the external light may sometimes be chromatic light that is deviated to a specific wavelength. At this time, an image displayed on the liquid crystal display panel 12 is displayed. In order to prevent the white balance from being lost, the illuminance of the backlight 13 is increased so as to minimize the influence of the external light β. That is, the output of the color sensor 18 of the external light β is guided to the illuminance control unit 32 via the internal sensor 33, and the light amount of the backlight 13 is controlled via the inverter 31. Further, when the color temperature of the external light β is very different from the normal temperature, the intensity is strong, and the influence of the external light β cannot be canceled only by increasing the illuminance of the backlight 13, the external light daylighting window 14 is set. It may be closed and illuminated only by the backlight 13.

As described above, the following effects can be obtained in the electronic camera 1 according to the first embodiment.

(1) The combined light quantity of the external light β taken in from the daylighting window 14 and the light α of the backlight 13 is measured, and a simple closed loop such that the measured value of the brightness of the liquid crystal display panel 12 becomes equal to the target value. By performing the control, the brightness of the backlight 13 can be automatically adjusted. In addition, by making the brightness control of the backlight 13 independent of the imaging optical system, it is possible to control the brightness independently of the brightness of the subject. Thereby, even if there is a large difference between the brightness of the subject and the external light β, the brightness of the image on the liquid crystal display panel 12 can be made appropriate.

On the other hand, the configuration of the illumination control system of the liquid crystal display panel becomes simple, no additional filter or the like is required, and the size and cost of the device can be reduced.

(2) Since the brightness of the backlight 13 is controlled based on the output of the color sensor 18,
When the color of the external light β is not suitable for the illumination, the effect can be minimized by increasing the illuminance of the backlight 13, and a white-balanced image can be obtained.

(3) If it is determined that the color temperature of the external light β is different from the normal color temperature, the illumination with the external light β is not performed, and only the backlight 13 is used to illuminate the image with white balance. Can be obtained.

(4) As for the image displayed on the liquid crystal display panel, the brightness of the illumination is always uniform, and a clear image close to natural light with white balance is obtained.

FIG. 3 is a sectional view showing a main part of an electronic camera 4 according to a second embodiment of the present invention. In this figure, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

In the electronic camera 4, a light guiding prism 41 is used, and the backlight 42 is
3 is provided below in FIG.

The same effect as that of the electronic camera according to the first embodiment can be obtained in the electronic camera according to the second embodiment.

It should be noted that the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

[0036]

According to the present invention, appropriate display can be easily performed irrespective of the brightness and color temperature of a subject and external light.

[Brief description of the drawings]

FIG. 1 is an exemplary sectional view showing a main part of an electronic camera according to a first embodiment of the present invention;

FIG. 2 is a block diagram showing a control system of a liquid crystal display panel of the electronic camera according to the embodiment of the present invention.

FIG. 3 is an exemplary sectional view showing a main part of an electronic camera according to a second embodiment of the invention;

[Explanation of symbols]

 1,4 ... Electronic camera 2 ... Camera body 3 ... Viewfinder 12 ... Liquid crystal display panel 13,41 ... Backlight 14 ... Lighting window 15,40 ... Light guide prism 17 ... Brightness sensor 18 ... Color sensor 26 ... External light Sensor 32: Illuminance control unit 33: Internal sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 364 H04N 5/225 F 5C065 H04N 5/225 9/04 B 5G435 9/04 G02F 1/1335 530 F term (reference) 2H088 EA25 HA23 HA28 HA30 MA05 MA06 2H091 FA21Z FA23Z FA41Z GA11 LA18 LA30 2H093 NC42 NC55 NC56 ND24 ND60 NE06 2H102 BA04 BB03 BB09 CA34 5C022 AA13 AB67 AC00 AC03 AC09 AC03 BB01 CB01 DD02 FF03 FF05 5G435 AA00 BB12 BB15 DD09 EE02 EE25 EE30 FF04 FF07 FF08 GG02 GG03 GG21 GG22 LL14

Claims (4)

[Claims] 1. A display device of a camera capable of illuminating a liquid crystal display panel with at least one light of a backlight or external light taken from a lighting unit, wherein the external light taken from the lighting unit and the backlight A camera comprising: a photometric element disposed at a position where light can be measured at the same time; and light amount adjusting means for adjusting brightness of the backlight based on an output of the photometric element. Display device. 2. A display device for a camera, comprising: a display unit capable of illuminating a liquid crystal display panel with at least one of external light taken from a backlight or a daylighting unit; and information on a color temperature of the external light. A camera display device comprising: a colorimetric unit for measuring the colorimetry; and a light amount adjusting unit for adjusting the brightness of the backlight based on an output of the colorimetric unit. 3. The liquid crystal display panel is illuminated by the backlight when the colorimetric means determines that the color temperature of the external light is different from the normal color temperature as a result of the colorimetry. Item 3. A display device for a camera according to Item 2. 4. An image displayed on the liquid crystal display panel,
3. The display device of a camera according to claim 2, wherein the image is an image whose white balance has been adjusted.