JPH09138400A - Illuminator for liquid crystal display body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the reduction of a cost, to restrain a battery from being consumed with a simple constitution. SOLUTION: This device is provided with a liquid crystal display body 19 and a holder 20 holding the body 19 and constituted of a conductive material guiding light to the body 19, and a light storing material converting energy absorbed in the case it is stimulated with light into visible light and keeping emitting the visible light after such stimulation is stopped is kneaded in the conductive material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an illuminating device for illuminating a liquid crystal display.

[0002]

2. Description of the Related Art In a conventional liquid crystal display illuminating device, a light source such as an LED guides light to a liquid crystal display by a light guide plate and the liquid crystal display is illuminated from the back side.
There is known a type in which an electroluminescence panel (hereinafter referred to as an EL panel) provided on the lower surface of a liquid crystal display body illuminates the liquid crystal display body.

In such an illuminating device, even when the surrounding brightness changes and becomes dark, if a light source such as an LED or an illuminating device such as an EL panel is turned on as necessary, a liquid crystal display is displayed. You can see the contents. However, when lighting devices such as LEDs and EL panels are kept on for a long time, there is a problem that battery consumption becomes faster. Further, when manually turning on and off the lighting device, operation switches are necessary, and when automatically turning on and off, a means for detecting the ambient brightness of the camera and determining whether or not the lighting is necessary. Therefore, there is a problem that the structure becomes complicated and the cost increases.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to illuminate a liquid crystal display body which has a simple structure and realizes cost reduction and battery consumption reduction based on the above problems in the conventional liquid crystal display body illumination device. The purpose is to provide a device.

[0005]

SUMMARY OF THE INVENTION The present invention for achieving the above object comprises a liquid crystal display body; and a holder made of a light guide material for holding the liquid crystal display body and guiding light to the liquid crystal display body. It is characterized in that the above-described light guide material is kneaded with a light storage material which converts the energy absorbed by the light stimulus into visible light and continues to emit the visible light even after the stimulus is stopped.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. FIG. 1 shows a strobe-equipped camera equipped with an illumination device for a liquid crystal display according to the present invention, and FIG. 2 is a partially enlarged cross-sectional view showing a main part around the illumination device of this camera. In both figures, a camera 11 with a built-in strobe has a photographing lens barrel 13 on a front decoration 12a of a camera body 12, and a stroboscopic light emitting unit (built-in strobe) 15 and a liquid crystal display illumination device 16 on a top decoration 12b. , And a release button 17. When the release button 17 is pressed when the subject brightness is insufficient in the automatic shooting mode or when the forced light emission mode is selected, the shutter mechanism (not shown) is driven to release the shutter and the condenser (Fig. A voltage for light emission from (not shown) is supplied to the xenon tube 23, and the xenon tube 23 emits light.

The illuminating device 16 is arranged on the side of the stroboscopic light emitting unit 15 and has a rectangular liquid crystal display body 19 for displaying various photographing information, and a storage recess 20a having substantially the same shape as the liquid crystal display body 19. Box-shaped holder 2 with and
It has 0. The liquid crystal display 19 has the storage recess 20.
In the state of being housed in a, the falling off from the holder 20 is restricted by a holding member (not shown). Top decoration part 12
An opening portion 21 for exposing the lighting device 16 arranged inside the top decoration portion 12b is formed in the central portion of b. A protective plate 18 made of a transparent material such as an acrylic plate is fitted into the opening 21 so that the information displayed on the liquid crystal display 19 can be viewed from the outside and protects the liquid crystal display 19.

The holder 20 as a whole has a storage recess 2
It is composed of a light guide material (for example, transparent plastic) that guides light to the liquid crystal display body 19 housed in 0a and illuminates the liquid crystal display body 19 from its back side. Then, a light storage material is kneaded with the light guide material forming the holder 20. This phosphorescent material has a property of converting energy absorbed by light stimulation into visible light and continuing to emit the visible light even after the stimulation is stopped. Further, the holder 20 is formed such that the storage recess 20a is moved closer to the rear side of the camera,
The front side of the camera has a larger area than the rear side of the lighting unit 20.
b.

The strobe light emitting unit 15 has a xenon tube 23 which is long in the left-right direction of the camera, and a reflector 22 which is located on the back surface of the xenon tube 23 and has a uniform cross section. The reflector 22 has slits 22a on the left and right side surfaces that extend from both ends of the xenon tube 23. The slit 22a is formed during the manufacturing process of the reflector 22. A strobe opening 24 facing the front opening of the reflector 22 is formed in front of the stroboscopic light emitting unit 15 in the camera body 12 with a slight distance from the reflector 22.
The Fresnel lens 14 is fitted in the strobe opening 24. The xenon tube 2 is provided between the strobe light emitting unit 15 and the lighting device 16 in the camera body 12.
Other components are not arranged so that stray light reflected by the Fresnel lens 14 at the time of light emission of No. 3 and leaked light from the slit 22a of the reflector 22 reach the holder 20.

The above-mentioned phosphorescent material is generally in the form of fine powder,
The main components are Al ₂ O ₃ , CaO, SrO, B ₂ O _3, etc., and the color of the material itself is pale yellow and the emission color is yellow. The excitation wavelength is 200 to 450 nm, and the emission peak wavelength is 52.
0 nm. The excitation means absorbing energy by receiving a stimulus of light such as sunlight or a fluorescent lamp. The initial brightness of the phosphorescent material is 2500 mcd / m ² or more, and the afterglow time is 20 hours or more. This initial brightness means that after storing the phosphorescent material in a state where the external light is blocked for 3 hours or more, the light of the common light source D ₆₅ is irradiated for 4 minutes at a brightness of 200 ± 101x, and 30 seconds after the irradiation is stopped. It is the brightness after. The afterglow time is the time required for the luminance to decay to 0.32 mcd / m ² . The phosphorescent material is
Since it is a chemically extremely stable crystal, it has the durability of semi-permanently retaining the functions of storing light and emitting light. The phosphorescent material having such a property can be kneaded (kneaded) into most synthetic resin materials and can be molded. The mixing ratio of the phosphorescent material at the time of kneading is set to about 10 relative to 100 of the synthetic resin material.

Now, the test results of the afterglow brightness of the light-storing material over time shown in FIG. 3 will be described. That is, the graph in the figure shows that different types of light-storing materials A and B, which have been shielded from light for 15 hours or longer in a room at room temperature of 25 ° C and a humidity of 65%, are 0.2 g on an aluminum dish with a diameter of 10 mm.
Each of the phosphorescent materials A and B was vertically irradiated with a 15 W fluorescent lamp from a distance of 20 cm for 15 minutes, and immediately after the light was turned off, the luminance was measured for a predetermined time by using a luminance meter and a lens with a diopter of 2 °. It is the result measured every time. In the figure, the vertical axis represents changes in luminance (mcd / m ² ) and the horizontal axis represents the passage of time (min).

In the figure, the phosphorescent material A has a light emission brightness of, for example, 2 after being turned off after being irradiated with a 15 W fluorescent lamp.
After 1 minute, it was 1362 mcd / m ² , after 5 minutes it was 610 mcd / m ² , and after 8 minutes it was 418
It becomes mcd / m ² , and after 20 minutes, it becomes 157 mcd / m ² .
m ² . After an additional 30 minutes, 89.7 mcd
/ M ² , and after 60 minutes, 53.8 mcd / m ²
After 180 minutes, it becomes 46.2 mcd / m ² . Although not shown, the phosphorescent material A continues to emit light while being attenuated thereafter, and emits visible afterglow for about 20 hours.

Further, the luminous material B has a light emission brightness of 96 after a lapse of 2 minutes after being turned off after being irradiated with a 15 W fluorescent lamp.
It becomes 0 mcd / m ² and after 5 minutes 426 mcd / m
It becomes m ² , becomes 267 mcd / m ² after 8 minutes, and becomes 107 mcd / m ² after 20 minutes. Further, after 30 minutes, it becomes 70.4 mcd / m ² , which is 6
After 0 minutes, it becomes 34.4 mcd / m ² , and after 180 minutes, it becomes 12.0 mcd / m ² . The light-storing material B is not as long as the light-storing material A in terms of time, but emits a visible afterglow while decaying thereafter.

As can be understood from the above, the light-storing materials A and B differ in the degree of attenuation of the light emission luminance from the time when the irradiation of light is stopped, but both of them have the following characteristics. It is possible to emit a visible afterglow for a relatively long time while gradually attenuating. Therefore, the holder 20 made of the light guide material obtained by kneading such a light storing material.
Absorbs outside light as energy from the daylighting section 20b, or the Fresnel lens 14 when the xenon tube 23 emits light.
Stray light reflected by the slits 22a of the reflector 22
By absorbing the leaked light as energy and converting this energy into visible light, the liquid crystal display body 19 can be continuously illuminated from the back side even after the light is blocked.

The flash built-in camera 11 having the above construction operates as follows. That is, this camera 1
While 1 is located in a bright place, holder 20
Absorbs the external light received by the daylighting section 20b as energy, converts this energy into visible light, and continues to emit light.
Therefore, since the holder 20 illuminates the liquid crystal display body 19 for a period of time according to the type of the phosphorescent material used and the amount of light received by the daylighting section 20b, the display content of the liquid crystal display body 19 is even in a dark place. It becomes visible. Also, when stroboscopic photography is performed as necessary, when a flash light is emitted from the xenon tube 23 based on the pressing operation of the release button 17,
Most of this flash is emitted from the strobe aperture 24 to the front of the camera (see arrow C in FIG. 1), but the Fresnel lens 1
Stray light reflected by 4 or slit 22a of reflector 22
Light leaking from the light impinges on the adjacent holder 20. Then, the stray light and the leaked light are held by the holder 20 made of a light guide material.
, The liquid crystal display 19 is illuminated from the back side, and at the same time, the holder 20 absorbs these stray light and leaked light as energy. And this holder 20
Even after the light is blocked, the absorbed energy is converted into visible light and the liquid crystal display body 19 is continuously illuminated for a time corresponding to the type of the light storing material and the amount of received light. Therefore, the display content of the liquid crystal display body 19 can be viewed even in a dark place.

As described above, the illumination of the liquid crystal display body 19 by the holder 20 is continuously performed for a predetermined time even after the light irradiation to the holder 20 is stopped. However, this illumination is performed when the periphery of the camera 11 is bright. Is negligible, and there is no problem as the lighting does not need battery power. In a dark place, if the camera 11 is placed in a bright place and within a predetermined time, the liquid crystal display 19
Can be continuously illuminated and the display content can be viewed. Further, according to the present embodiment, when it is desired to confirm the photographing information displayed on the liquid crystal display 19 in a dark place, the liquid crystal display 19 can be obtained by stroboscopic photography and causing the xenon tube 23 to emit light.
Lighting time can be extended. As described above, since the lighting device 16 does not consume the battery power particularly for lighting, it is possible to save the power and suppress the consumption of the battery of the camera.

Further, since the illumination device 16 of the present liquid crystal display body does not need to switch the illumination on and off for the liquid crystal display body 19, operation switches for manually turning on and off, and for automatically turning on and off. No need for means for determining necessity or non-necessity, the device configuration can be simplified, and the cost can be reduced. Further, when it is necessary to frequently confirm the shooting information of the liquid crystal display body 19, it is not necessary to repeatedly press the manual operation button or the like, so that the mobility of the camera is improved.

The reflector 22 and the xenon tube 23
When, for example, is housed in a strobe case (not shown) having an opening on the Fresnel lens 14 side and provided on the camera body 12, a reflector 22 for emitting light from the xenon tube 23 is provided on the wall of the strobe case on the holder 20 side. It suffices to provide an opening for emitting the leaked light from the slit 22a.

Further, in the above embodiment, the illuminating device for the liquid crystal display body of the present invention has been described with respect to the illuminating device 16 for the liquid crystal display body 19 for displaying various photographing information provided in the camera with a built-in strobe. Without being limited to examples
It can also be used in other devices using a liquid crystal display. In this case, if the device has a light emitting means such as a strobe of a camera, the holder is arranged at a position where the light from the light emitting means can be received, and the device does not have such a light emitting means. If so, the daylighting unit as in the above-described embodiment is provided to take in outside light.

[0020]

As described above, according to the present invention, the light guide material forming the holder of the liquid crystal display converts the energy absorbed by the light stimulus into visible light, and the visible light is maintained even after the stimulus is stopped. Since the light-storing material that continues to emit light is kneaded, it is possible to provide a lighting device for a liquid crystal display that has a simple configuration, realizes cost reduction, and can reduce battery consumption.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a camera with a built-in strobe equipped with an illumination device for a liquid crystal display according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a main part around the illumination device of the camera.

FIG. 3 is a diagram showing a graph of test results regarding afterglow brightness of a light-storing material over time.

[Explanation of symbols]

 11 Strobe Built-in Camera 12 Camera Body 15 Strobe Light Emitting Unit (Built-in Strobe) 16 Liquid Crystal Display Illumination Device 19 Liquid Crystal Display 20 Holder 20a Storage Recess 20b Lighting Area 22 Reflector 22a Slit 23 Xenon Tube

Claims (4)

[Claims] 1. A liquid crystal display body; and a holder made of a light guide material that holds the liquid crystal display body and guides light to the liquid crystal display body; A lighting device for a liquid crystal display, comprising: a light-storing material that is kneaded to convert energy absorbed to visible light and continues to emit the visible light even after the stimulation is stopped. 2. The holder according to claim 1, wherein the holder is provided at a position adjacent to a built-in strobe in a built-in strobe camera, and receives stray light reflected by a Fresnel lens provided in front of the built-in strobe when the built-in strobe emits light. An illuminating device for a liquid crystal display, characterized by: 3. The holder according to claim 1, wherein the holder is provided at a position adjacent to the built-in strobe in the built-in strobe camera, and receives light leaking from a slit of a reflector provided in the built-in strobe when the built-in strobe emits light. Characteristic liquid crystal display lighting device. 4. The housing according to claim 2, wherein the holder is exposed to the outside of the camera body together with the accommodating recess for accommodating the liquid crystal display body and the liquid crystal display in the accommodating recess. An illuminating device for a liquid crystal display, wherein the illuminating unit is configured as a lighting unit that receives light from outside the camera body.