JPH0815703A - Irradiation mechanism for lcd - Google Patents

Abstract

PURPOSE:To obtain the irradiation mechanism of an LCD constituted so that the LCD is efficiently irradiated by using both of the light of a back light and external light such as solar light and the display screen of the LCD can be brightly viewed under any condition. CONSTITUTION:The back light 2 is arranged at the back part of the LCD 1 and two prism blocks 3 and 4 respectively joined at joining surfaces 3a and 4a are arranged between the LCD 1 and the back light 2 in a state where the positions thereof are fixed to a prism holder. The surface of one block 3 faced to the back light 2 is used as a light incident surface 12 and the surface thereof faced to the LCD 1 is used as a light emitting surface 16 provided with a light diffusion surface 16A. Then, a Fresnel lens 19 is formed by one surface of the other block 4 so as to be faced to an external light incident window and the external light incident window is provided with an external light transmission member 22 having a light diffusion surface 22A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination mechanism suitable for use as a backlight of a liquid crystal display device (hereinafter referred to as LCD) in a viewfinder of a video camera recorder (camera integrated VTR). .

[0002]

2. Description of the Related Art Conventionally, in a viewfinder device of a video camera recorder of this type, a color liquid crystal display device is used, and a backlight is arranged behind a liquid crystal panel of the color liquid crystal display device. Makes the image on the surface of the LCD panel look bright.

[0003]

However, when shooting outdoors with a video camera on a day with strong sunlight, the amount of light from the pack lamp is much smaller than that of sunlight, so the image on the surface of the liquid crystal panel seems to be extremely dark. There was a problem. In particular, this phenomenon becomes remarkable when the sunlight is obliquely forward and upward from the front of the subject and the sunlight is reflected by, for example, the operator's eyeglasses and enters the viewfinder.

If the power consumption of the battery is increased in order to increase the light quantity of the backlight as a method for solving this problem, the life time of the battery is shortened, which is not practical.

The present invention has been made in order to solve the above-mentioned problems, and efficiently illuminates the LCD by using a combination of backlight light and external light such as sunlight, and the LCD display screen under all conditions. It is an object of the present invention to obtain an illumination mechanism of an LCD that allows the user to see brightly.

[0006]

In order to achieve the above-mentioned object, the illumination mechanism of the LCD according to the present invention is such that the display screen of the LCD 1 is illuminated by backlight light to illuminate the display screen of the LCD 1. At LCD1
The light source 2 as the backlight, which is placed behind the
A prism member 5 disposed between the CD 1 and the light source 2 and an external light incident window 20 formed so as to correspond to at least one surface of the prism member 5 are provided, and correspond to the external light incident window 20 of the prism member 5. External light is applied to the surface to
A light condensing surface 19 for condensing on the CD 1 side, and a surface of the prism member 5 corresponding to the light source 2 also serves as a light incident surface 1 of the light source that also serves as a reflection surface of the external light incident on the prism member 5 through the external light incident window 20.
2, the surface of the prism member 5 corresponding to the LCD 1 is the light emitting surface 16 of the light source and the external light.

LC according to the preferred embodiment of the present invention
The illumination mechanism D has a Fresnel lens 19 on its light collecting surface.

LC according to the preferred embodiment of the present invention
In the illumination mechanism D, an external light transmitting member 22 having a bright light diffusing surface 22A with a small amount of dispersed light is provided in the external light incident window 20 so as to face the light collecting surface 19 of the prism member 5.

LC according to the preferred embodiment of the present invention
In the illumination mechanism D, the light exit surface 16 of the prism member 5 is formed with a bright light diffusion surface 16A with little dispersed light.

LC according to the preferred embodiment of the present invention
In the illumination mechanism of D, the prism member 5 is a combination of a plurality of prism blocks 3 and 4 having joint surfaces 3a and 4a.

Further, L according to the preferred embodiment of the present invention.
In the CD illumination mechanism, a plurality of prism blocks 3 and 4 are engaged with a prism holder 6 by engaging means 7, 8 and 10, 11 to fix the prism blocks 3 and 4 in position.

[0012]

The illumination mechanism of the LCD according to the present invention configured as described above includes a light source 2 serving as backlight light disposed behind the LCD 1, a prism member 5 disposed between the LCD 1 and the light source 2, and this prism. An external light incident window 20 formed so as to correspond to at least one surface of the member 5, and a surface of the prism member 5 corresponding to the external light incident window 20 collects external light on the LCD side by a lens action. The surface of the prism member 5 corresponding to the light source 2 is the light incident surface 12 of the light source that also serves as a reflection surface of the external light incident on the prism member 5 through the external light incident window 20.
Since the surface corresponding to 1 is the light source 2 and the light emitting surface 16 of the external light, the light from the light source 2 receives the light incident surface 12 of the prism member 5.
To pass through the prism member 5 and exit from the light exit surface 16 of the prism member 5 to illuminate the LCD 1. Further, the external light incident from the external light entrance window 20 is condensed into the prism member 5 by the condensing surface 19 of the prism member 5, and most of the condensed external light is the light exit surface of the prism member 5. The LCD 1 is irradiated with external light emitted from the LCD 16, and at the same time, a part of the condensed external light is reflected by the light incident surface 12 of the prism member 5 and emitted to the LCD 1 as external light emitted from the light emitting surface 16.

Further, since the converging surface is composed of the Fresnel lens 19, the external light incident from the external light entrance window 20 is effectively condensed by the lens condensing function of the Fresnel lens 19 into the prism member 5. It is possible to emit light and guide these external light to the LCD 1 side.

Further, since the external light incident window 20 is provided with the light transmitting member 22 having the bright light diffusing surface 22A with a small amount of dispersed light so as to face the light collecting surface 19 of the prism member 5, the entire light diffusing surface 22A is provided. The outside light is diffused as a bright light with no unevenness, and the diffused light is condensed onto the condensing surface 1 of the prism member 5.
9 can be irradiated.

In addition, since the bright light diffusion surface 16A with little dispersed light is formed on the light exit surface 16 of the prism member 5,
External light can be diffused as bright light without unevenness on the entire light diffusion surface 16A, and the LCD 1 can be irradiated with this diffused light.

Further, the prism member 5 has the joint surfaces 3a and 4a.
By combining a plurality of prism blocks 3 and 4 each having a light source 2 from the light source 2 to the light incident surface 1 of the prism member 5.
It is possible to reflect a part of the light that has entered the prism from 2 through the joint surfaces 3a and 4a of the prism blocks 3 and 4, and effectively guide the reflected light to the LCD 1 side.

Further, the plurality of prism blocks 3 and 4 are engaged with the prism holder 6 by the engaging means 7, 8 and 10, 11 so as to fix the prism blocks 3 and 4 in position. , 4 mutual bonding surfaces 3a, 4a of the air gap amount and position accuracy can be easily set.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an LCD illumination mechanism according to the present invention will be described below with reference to the drawings by taking a viewfinder of a video camera recorder as an example. 1 is an exploded perspective view of the structure of the viewfinder of this embodiment, FIG. 2 is a sectional view of the viewfinder in an assembled state, and FIG.
FIG. 3 is an enlarged view of the LCD illumination mechanism of the essential part of the present invention.

In each of the drawings, reference numeral 1 denotes an LCD (liquid crystal display device), and the LCD 1 is held at the rear end portion of a lens barrel described later. A backlight 2 as a light source is arranged behind the LCD 1. A prism member 5 including a plurality of prism blocks 3 and 4 is arranged between the LCD 1 and the backlight 2.

Here, the structure of the LCD 1, the backlight 2, and the prism member 5 which are the gist of the present invention will be described. The optical details will be described later.

Both prism blocks 3 and 4 constituting the prism member 5 are made of, for example, an acrylic material having a high light transmittance, and the prisms are combined in a state in which the respective one surfaces 3a and 4a are combined so as to be substantially joined to each other. It is held by the holder 6. The lower prism block 3 is held by engaging horizontal guide protrusions 7, 7 provided on both side surfaces thereof with guide grooves 8, 8 formed in the prism holder 6, and the back surface of the prism block 3 is covered with a cushion member 9. It is supported by the prism holder 6 through. Upper prism block 4
Also, horizontal guide protrusions 10, 10 provided on both side surfaces thereof are engaged with and held by the guide grooves 11, 11 of the prism holder 6. As a result, both prism blocks 3 and 4 are accurately fixed in position with predetermined positional accuracy. FIG. 4 shows a side cross-sectional view of a state in which the above-mentioned prism blocks 3 and 4 are held by the prism holder 6.

The rear surface of the lower prism block 3 serves as a light incident surface 12 on which the lamp light of the above-described backlight 2 is incident, and an opening window 13 is formed in a portion of the prism holder 6 corresponding to the light incident surface 12. . The backlight 2 is supported by the prism holder 6 from the back side so as to correspond to the opening window 13. In addition, 14 is a light-condensing sheet provided on the front surface of the backlight 2, and 15 is a substrate on which the backlight 2 is electrically wired and held.

The front surface of the prism block 3 is an LCD.
1 is a light emitting surface 16 for irradiating light to the light source 1.
A reflection sheet 17 for blocking the incidence of light on the area other than the panel surface of the LCD 1 is arranged at 6, and the light emitting surface 16 is joined to the back surface of the LCD 1 via a cushion member 18.

On the other hand, the upper surface of the upper prism block 4 is formed with a Fresnel lens 19 which serves as a converging surface for external light such as sunlight, and each flat surface of the Fresnel lens 19 has a large number of continuous lens surfaces 19a. Has become.

An external light incident window 20 is formed on the Fresnel lens 19 described above. The outside light incident window 20 is formed in one finder cabinet 21 in which the backlight 2, the substrate 15 of the backlight 2, and the prism holder 6 that houses the prism blocks 3 and 4 are housed. An external light transmitting member 22 is fitted in the external light incident window 20.

Here, the lens barrel holding the LCD 1 is composed of an upper lens barrel 23 and a lower lens barrel 24 in a split shape, and the upper and lower lens barrels 23, 24 have a first finder lens from the LCD 1 side. 25, a filter 26, a second finder lens 27 and a diopter lens 28 are held. The diopter lens 28 has its lens frame 28 by an adjusting means (not shown).
It can be moved in the optical axis direction together with a.

The upper lens barrel 23 and the lower lens barrel 24 are joined to the prism holder 6 described above. This connecting structure is the lower lens barrel 24.
Has projections 29, 29 on both side surfaces thereof, and engaging holes 31, 31 are provided at the tip end portions of spring pieces 30, 30 elastically deformed inward and outward on both side surfaces of the prism holder 6. That is, by pushing the prism holder 6 and the lens barrel in the assembled state from such a structure, the projections 29, 29 and the engaging holes 31,
31 and 31 are brought into an engaged state and can be integrally connected.

The upper and lower lens barrels 23 and 24 are housed in another finder cabinet 32. A lens cover 34 is attached to the tip of the finder cabinet 32 via a cover retainer 33, and an eyecup 35 is attached to the cover retainer 33.

Reference numeral 36 denotes a viewfinder power supply system substrate, and this substrate 35 is held and fixed by engaging claws 37 formed on the prism holder 6 and the lower lens barrel 24. Reference numeral 38 denotes a viewfinder signal system board, and this board 38 is an engaging claw 39 formed on the upper lens barrel 23.
It is held and fixed by.

The finder cabinet 32 and the above-mentioned finder cabinet 21 are joined by the joining means 40.

The viewfinder constructed in this way is
A base member 41 fixed to a video camera recorder (not shown), and a link member 42 rotatably supported on the back surface of the base member 41 and the finder cabinet 21.
The tilt mechanism composed of and is configured to be tiltable.

Here, the optical configuration of the prism blocks 3 and 4 and the external light transmitting member 22 which are the main parts of the present invention will be described with reference to FIG.

The two prism blocks 3 and 4 are so-called air gaps 4 in which the respective joint surfaces 3a and 4a are slightly separated in the state where the prism blocks 3 and 4 are fixed in position.
3 are formed. In addition, both prism blocks 3 and 4
The angle formed by the joint surfaces 3a and 4a of the
The optical axis is set to about 45 °.

On the other hand, the light exit surface 16 of the prism block 3
Is formed on the bright light diffusing surface 16A with less scattered light, which reduces the scattering of light emitted from here. Similarly, the surface of the external light transmitting member 22 corresponding to the Fresnel lens 19 of the prism block 4 is also formed as a bright light diffusing surface 22A with little dispersed light. These light diffusing surfaces 16A and 22A are generally used as a finder screen of a camera. The prism block 3
The light incident surface 12 also serves as a reflection surface for the light transmitted through the block 3.

Fresnel lens 19 of prism block 4
Is configured on the lens surface 19a in such a direction that external light incident from the upper front or diagonally upper front of the subject can be efficiently condensed to the LCD 1 side.

Next, the function of illuminating the backlight 2 and the external light with respect to the LCD 1 will be described with reference to FIG. First, most of the light from the backlight 2 becomes a light ray L ₁ and a on the light incident surface 12 of the prism block 3
The light is refracted at a point, enters the prism, and exits from the light exit surface 16. At this time, the light diffusing surface 16A of the light exiting surface 16 produces bright light with little scattered light and no unevenness in the LCD 1.
To illuminate. Further, a part of the light from the backlight 2 is refracted at the point b on the light incident surface 12 of the prism block 3 so that the light ray L ₂ enters the prism. Here, for example, when the prism blocks 3 and 4 are integrally formed and there is no joint surface, b
The light refracted at the point goes straight as shown by the broken line and becomes leaked light, but the light refracted at the point b at the point c on the cemented surface 3a due to the two prism blocks 3 and 4 being composed of two members. The light reaches the light emitting surface 16 which is reflected and does not face the LCD 1. Then, this light is reflected by a reflection sheet 17 (see FIG. 2) not shown here and again enters the prism block 3, and most of it enters the LCD 1 side. Therefore, most of the light quantity from the backlight 2 can be efficiently illuminated on the LCD 1.

On the other hand, outside light such as sunlight is transmitted through the light incident window.
It is incident from the external light transmitting member 22. Enter the external light transmission member 22
Outside light L₃First, the light diffusing surface 2 of the external light transmitting member 22.
2A produces bright light with little scattered light and no unevenness.
Is transparent. And this diffused light is a prism block
It is condensed by the Fresnel lens 19 of 4 and the prism block
It is incident on the dock 4. Most of this incident light is a prism
Next to the joint surface 4a of the block 4 via the air cap 43.
Go straight into the prism block 3 from the contact surface 3a
Shoot. In addition, a part of the external light L in the prism block 4_Four
Is reflected at a point d on a surface other than the bonding surface 4a, and
In the same manner as above, the air from the joint surface 4a of the prism block 4
The prism block from the joint surface 3a adjacent via the cap 43.
It goes straight into the lock 3 and enters. And the prism block
External light L condensed inside₃, L _FourIs a prism block
By the light diffusion surface 16A of the light exit surface 16 of 3
It illuminates the LCD 1 by emitting a bright light with no unevenness of light.
I do.

As described above, the illumination mechanism of the LCD according to the present invention utilizes the light from the backlight 2 and the external light taken in from the outside at the same time, and efficiently transmits these lights by the LC.
It is possible to illuminate D1, which has an advantage that the bright liquid crystal screen of the LCD 1 can be seen even when shooting with a video camera outdoors in strong sunlight. Further, since the Fresnel lens 19 is formed on the outside light incident surface of the prism block 3, the amount of outside light can be effectively condensed to the LCD 1 side, and as a result, the sunlight is backlit when the image is taken by the video camera. It can be seen as an extremely bright liquid crystal screen even when it's time.

The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

In the embodiment, the use example in which the light of the backlight 2 and the outside light are simultaneously illuminated to the LCD 1 has been described. However, the backlight 2 is used in the outdoors where the sunlight is strong.
The LCD 1 may be illuminated by turning off the light and using only the external light. By doing so, the battery life can be extended. In this case, the brightness of the LCD is 2.5 times when the backlight and the outside light are used together, whereas the brightness is reduced to 1.5 times when the outside light alone is used, but it is practically possible.

Further, the Fresnel lens 19 of the prism block 4 allows the outside light of the sunlight in the case of backlight against the subject to be L.
Although the configuration is made so that the light can be concentrated on the CD1 side, it is also possible to use a Fresnel lens having a lens surface that allows external light from all directions to be condensed on the LCD1 side.

Further, instead of the Fresnel lens 19 of the prism block 4, as shown in FIG.
Even if the lens film sheet 45 having a light condensing function is attached to the flat surface 44, the same effect as described above can be obtained.

Further, the above-mentioned lens film sheet 45 may be attached to the upper surface of the Fresnel lens 19 of the prism block 4 as shown in FIG. 6, and by doing so, the lens film sheet 45 and the Fresnel lens 1 are attached.
The double condensing action with 9 can further enhance the condensing of external light on the LCD 1 side.

Further, the prism blocks 3 and 4 are shown in the case where the air gaps 43 are formed on the respective joint surfaces 3a and 4a. However, since the air gap 43 is not provided, the transmission efficiency of external light can be improved, and thus the prism blocks 3 and 4 are joined. Faces 3a, 4a
May be joined together. Alternatively, the prism blocks 3 and 4 may be integrally configured. By doing so, the external light incident from the Fresnel lens 19 can be effectively guided to the LCD side.

Further, although the LCD illumination mechanism of the present invention has been described as an LCD illumination mechanism of a video camera recorder, it can be widely applied as a liquid crystal display screen 1 illumination mechanism of a personal computer, a word processor or the like.

[0046]

As described above, the LC according to the present invention
The illumination mechanism D is a light source as a backlight arranged behind the LCD, a prism member arranged between the LCD and the light source, and external light incidence formed so as to correspond to at least one surface of the prism member. A surface of the prism member corresponding to the external light incident window is a light condensing surface for condensing the external light to the LCD side by the lens action, and the surface of the prism member corresponding to the light source is the external light incident window to the prism member. Since the light incident surface of the light source that also serves as a reflection surface of the external light incident on the inside is used and the surface of the prism member corresponding to the LCD is the light emitting surface of the light source and the external light, the light of the backlight and the external light are efficiently The effect is that the bright liquid crystal screen of the LCD can be seen when shooting with a video camera outdoors in strong sunlight.

Further, since the condensing surface is composed of the Fresnel lens, the external light can be condensed into the prism member by the lens condensing function of the Fresnel lens, and the external light can be effectively guided to the LCD side. .

Further, by providing a light transmitting member having a bright light diffusing surface with a small amount of dispersed light so as to face the light collecting surface of the prism member in the outside light incident window, the outside light is unevenly scattered on the entire light diffusing surface. However, the diffused light can be diffused as bright light, and the diffused light can be applied to the condensing surface of the prism member.

By forming a bright light diffusing surface with a small amount of dispersed light on the light exit surface of the prism member, external light is diffused as bright light without unevenness on the entire light diffusing surface, and this diffused light is applied to the LCD. can do.

The prism member is composed of a plurality of prism blocks, so that the light from the light source is LC
It can be effectively led to the D side.

Further, since the plurality of prism blocks are engaged with the prism holder by the engaging means to fix the positions of the prism blocks to each other, it is possible to easily set the air gap amount and the positional accuracy of the joint surfaces of the prism blocks. can do.

[Brief description of drawings]

FIG. 1 is a perspective view of a disassembled state of a viewfinder having an illumination mechanism of the present invention.

FIG. 2 is a cross-sectional view of an assembled state of a viewfinder having an illumination mechanism of the present invention.

FIG. 3 is a configuration diagram of an illumination mechanism that is a main part of the present invention.

FIG. 4 is a side sectional view of a holding state of a prism block.

FIG. 5 is a configuration diagram of another example of the light collecting surface of the prism block.

FIG. 6 is a configuration diagram of another example of the light collecting surface of the prism block.

[Explanation of symbols]

 1 LCD 2 Backlight 3,4 Blism Block 3a, 4a Bonding Surface 5 Prism Member 6 Prism Holder 7, 10 Guide Protrusion 8, 11 Guide Groove 12 Light Incident Surface 13 Opening Window 16A Light Diffusing Surface 19 Fresnel Lens 19a Lens Surface 20 Outside light incident window 21, 32 Fan-side cabinet 22 Outside light transmitting member 22A Light diffusing surface 23 Upper lens barrel 24 Lower lens barrel 43 Air gap

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[Procedure amendment]

[Submission date] August 19, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

On the other hand, the light exit surface 16 of the prism block 3
Is formed on the bright light diffusing surface 16A with less scattered light, which reduces the scattering of light emitted from here. Similarly, the surface of the external light transmitting member 22 corresponding to the Fresnel lens 19 of the prism block 4 is also formed as a bright light diffusing surface 22A with little dispersed light. These light diffusing surfaces 16A and 22A are generally used as a finder screen of a camera, and are regularly arranged as an example.
Forming a micropattern on the surface with no edging edges
Is possible by. The light incident surface 12 of the prism block 3 also serves as a reflection surface of the light transmitted through the block 3.

Claims (6)

[Claims] 1. An illumination mechanism adapted to illuminate a display screen of an LCD (liquid crystal display device) with backlight light to illuminate the display screen of the LCD, wherein a light source as backlight light arranged behind the LCD. A prism member disposed between the LCD and the light source, and an external light incident window formed so as to correspond to at least one surface of the prism member. The prism member corresponds to the external light incident window of the prism member. The surface of the prism member corresponding to the light source is a reflection surface of the external light incident on the prism member through the external light incident window. The light incident surface of the light source which also serves as
An illumination mechanism for an LCD, wherein the surface corresponding to the CD is the light source and the light emission surface of the external light. 2. The illumination mechanism for an LCD according to claim 1, wherein the condensing surface is a Fresnel lens. 3. The light transmitting member having a bright light diffusing surface with little dispersed light so as to face the light collecting surface of the prism member, is provided in the outside light incident window. LCD illumination mechanism. 4. The illumination mechanism for an LCD according to claim 1, wherein a bright light diffusing surface with little dispersed light is formed on the light exit surface of the prism member. 5. The illumination mechanism for an LCD according to claim 1, wherein the prism member is formed by combining a plurality of prism blocks having a joint surface. 6. The illumination mechanism for an LCD according to claim 4, wherein the plurality of prism blocks are engaged with prism holders by engaging means to fix the positions of the prism blocks relative to each other.