JP2002221720A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device, which directs the light from a light source of the side light system to the back of a liquid crystal display panel through a light guide plate, with light weight and at a low price by simplifying the structure. SOLUTION: The liquid crystal display device is constructed by fixing the light guide plate 12 and the liquid crystal display device 15 to a lower holding case 1 with a predetermined positional relationship therebetween with engaging projections 2a and 2b, which are integrally formed with the lower holding case 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used for a viewfinder device of a video camera or an electronic still camera, and more particularly to simplifying a structure including a sidelight type backlight. It has features. Here, the liquid crystal display device means a device that includes a light source such as a light emitting element and a display device (light modulating means) such as a liquid crystal display panel that is not of a self-luminous type, and both are integrated. Such a liquid crystal display device can be used for various display devices such as a video camera, an electronic still camera, and a pocket television.

[0002]

2. Description of the Related Art Video equipment such as a video camera using a viewfinder is required to be small and light in weight and low in power consumption from the viewpoint of portability and operability. The small size and the light weight limit the capacity of the battery that can be mounted, and as a result, the demand for lower power consumption becomes stronger. Therefore, the viewfinder is also required to have low power consumption. However, even if a low power consumption liquid crystal display panel is used, if the power for the backlight is large, the power consumption will not be reduced as a whole. For example, in a viewfinder using a liquid crystal display panel having an effective display area of 0.5 inches, a liquid crystal display and a driving circuit are 0.3 W, a backlight light source using a high-frequency lighting circuit is about 0.4 W, and a total of 0.7 W is used. Power consumption. Therefore, it is desired to reduce the power consumption of the lighting device constituting the viewfinder.

As a method of realizing low power consumption of a backlight light source, there is a side light type configuration using a light guide plate as a light source with a light emitting element not requiring a high frequency lighting circuit. FIG. 4 shows an example of the appearance of a conventional viewfinder. FIG. 5 shows a cross-sectional structure. In the body 40, the liquid crystal display panel 15 and a side light type backlight 52 are held and stored in a holding frame 41. An eyepiece ring 50 is stored in the body 40, and a magnifying lens 20 is disposed inside the eyepiece ring. By adjusting the degree of insertion of the eyepiece ring, the focus can be adjusted in accordance with the eyesight of the observer.

FIG. 6 shows a configuration of a conventional side light type backlight light source 52. 6, reference numeral 70 denotes a metal holding frame, 11 denotes a reflecting material, 12 denotes a light guide plate, 17 denotes a light source, and 74 denotes optical sheets. The metal holding frame 70 allows the reflecting material 11, the light guide plate 12, the light source 17, the optical This is a structure in which the sheets 74 are integrated and fixed. For the optical sheets 74, one or more prism sheets are selected as necessary for the purpose of increasing the directivity of a diffused sheet created by embossing or the like or light diffused by the diffused sheet. Used. Normally, a white LED or the like is used as the light source 17, and a wiring (not shown) for emitting the LED is required between the light source 17 and a circuit board.

[0005] The backlight light source 52 having the above-described structure.
Is integrated with the liquid crystal display panel 15 by the holding frame 41 as shown in FIG. This liquid crystal display panel is also connected to the liquid crystal drive circuit board.

[0006]

As described above, the conventional backlight is assembled as one part by the metal holding frame 70 as the backlight 52, and the assembled backlight 52 is placed in a predetermined positional relationship with the liquid crystal display panel 15. Thus, the holding frame 41 is used for integration.
That is, after the reflector 11, the light guide plate 12, the light source 17, and the optical sheet 74 are held by the metal holding frame 70,
The metal holding frame 70 is fixed to the holding frame 41, which is not preferable as a viewfinder for which reduction in size and weight is desired. An object of the present invention is to provide a small and lightweight liquid crystal display device of a sidelight system.

[0007]

In order to solve the above-mentioned problems, a liquid crystal display device according to the present invention irradiates light from a sidelight type light source to a rear surface of a liquid crystal display panel via a light guide plate. In the above, the light guide plate and the liquid crystal display panel are both directly held in the same holding case, and the light guide plate and the liquid crystal display panel are held directly in the holding case, so that in the conventional pre-process, The backlight device thus produced is assembled together with the liquid crystal display panel in a holding case to be connected to the liquid crystal display device.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The liquid crystal display device according to claim 1 of the present invention is a liquid crystal display device for irradiating light from a side light type light source to a rear surface of a liquid crystal display panel via a light guide plate. A liquid crystal display device characterized in that both the light plate and the liquid crystal display panel are directly held in the same holding case. Conventionally, the backlight is assembled as one part by a metal holding frame or the like as the backlight, and the assembled backlight is The light has been integrated with the liquid crystal display panel by a holding frame so as to have a predetermined positional relationship. That is, the reflector, the light guide plate, the light source, the optical sheet, and the like are held by the metal holding frame, and then the metal holding frame is fixed to the holding frame. This is preferable as a viewfinder for which a reduction in size and weight is desired. However, according to the present invention, since the backlight can be assembled on the same holding case, a small and lightweight liquid crystal display device can be provided. According to a second aspect of the present invention, in the liquid crystal display device, the positions of the light guide plate and the liquid crystal display panel in the holding case are regulated by engagement projections formed integrally with the holding case. 2. The liquid crystal display device according to claim 1, wherein the mounting positions of the light guide plate and the liquid crystal display panel are regulated by the engagement protrusions formed integrally with the holding case, so that the positional relationship between the two is easily achieved. Can be regulated in a predetermined relationship. The liquid crystal display device according to claim 3 of the present invention, wherein the holding case includes a box-shaped lower holding case having one side surface and an upper surface opened, and an upper holding case covering the upper surface opening of the lower holding case. 2. The liquid crystal display device according to claim 1, wherein a side wall of the lower holding case that faces the open side surface is formed in a shape along the shape of the light guide plate. 3. However, since the light guide plate is formed in a shape following the shape of the light guide plate, the light guide plate can be easily and stably attached.

According to a fourth aspect of the present invention, there is provided a liquid crystal display device comprising:
The liquid crystal display device according to claim 3, wherein the light guide plate is pressed and fixed to a side wall facing an open side surface of the lower holding case via a reflective material,
The light guide plate can be easily and reliably attached to a predetermined position.

[0010] The liquid crystal display device according to claim 5 of the present invention,
4. The liquid crystal display device according to claim 3, wherein an open side surface of the lower holding case is sealed with a light transmissive material, and the inside of the holding case is sealed after assembly. Therefore, the liquid crystal display panel and the like are not contaminated by foreign substances such as dust. 7. The liquid crystal display device according to claim 6, wherein the upper holding case irradiates the light guide plate when the upper holding case is arranged at a predetermined position covering the upper opening of the lower holding case. 4. A light source is disposed in the light source.
In the liquid crystal display device described above, since the light source is arranged in the upper holding case forming the holding case, the assembly such as the positional relationship between the light source and the light guide plate is facilitated.

According to a seventh aspect of the present invention, there is provided a liquid crystal display device comprising:
4. The liquid crystal display device according to claim 3, wherein a driving circuit for driving the liquid crystal display panel is provided in the upper holding case, and the driving circuit is mounted on the upper holding case fixed to the lower holding case. Is provided, which is close to the liquid crystal display panel in the holding case, which is convenient for miniaturization.

The liquid crystal display device according to claim 8 of the present invention,
4. The liquid crystal display device according to claim 3, wherein the upper holding case is also formed with an engagement protrusion for regulating positions of the light guide plate and the liquid crystal display panel. Is more certain.

According to a ninth aspect of the present invention, there is provided a liquid crystal display device comprising:
The upper holding case and the lower holding case are integrally formed with light shielding walls for preventing light emitted from the liquid crystal display panel from being reflected by the inner wall of the holding case and reaching the eyes of the observer. In the liquid crystal display device according to the third aspect, since the light shielding wall is formed integrally with the upper and lower holding cases, the manufacturing and assembling thereof is simplified.

The liquid crystal display device according to a tenth aspect of the present invention is characterized in that a light-reflecting surface is formed by using a reflective material on a side wall facing the open side surface of the lower holding case. The liquid crystal display device according to claim 3, wherein the side wall itself serves as a reflector, so that it is not necessary to provide a new reflector.

The liquid crystal display device according to claim 11 of the present invention reflects light from a light source provided on a circuit board fixed outside the side wall of the lower holding case and irradiates the light guide plate with the light. 4. The liquid crystal display device according to claim 3, wherein a plate is provided on the upper holding case, and the circuit board can be fixed to a side wall of the holding case. It will increase. (Embodiment 1) An embodiment of the present invention described in claims 1 to 10 of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view of main components of the present invention, and FIG. 2 is a cross-sectional view. 1 and 2, reference numeral 1 denotes a lower holding case made of a substantially square box-shaped synthetic resin material whose upper surface and one side surface are open, and a side surface 1a opposed to the open side surface is inclined downward. ing. further,
Inside the lower holding case 1, a U-shaped first engagement protrusion 2a, a second engagement protrusion 2b, a third engagement protrusion 2c and a fourth engagement The protrusions 2d are integrally formed so as to be parallel to each other at predetermined intervals. And the reflection material 1
1. The light guide plate 12 and the optical sheet 13 are inserted and held between the side surface 1a and the first engagement protrusion 2a.
At this time, the inclination of the side surface 1a has an inclination in consideration of the shape of the light guide plate 12, and the reflecting material 11 is configured to be in a state along the side surface. Further, the cushioning material 14
And the liquid crystal display panel 15 are inserted and held between the first engagement protrusion 2a and the second engagement protrusion 2b, and between the third engagement protrusion 2c and the fourth engagement protrusion 2d. The light transmissive material 16 is inserted and held. In this state, the upper holding case 3 is placed and fixed on the upper surface of the lower holding case 1. At this time,
On the lower surface of the upper holding case 3, the fifth, sixth, seventh, and eighth engaging protrusions 4a, 4a, 4b,
4c and 4d are formed to engage and hold the upper ends of the reflector 11, the light guide plate 12, the optical sheet 13, the buffer 14, the liquid crystal display panel 15, and the light transmitting material 16. A circuit board 18 is fixed to the upper surface of the upper holding case 3, and a light source 17 serving as a backlight light source is provided on the back surface of the circuit board 18. The upper end of the light guide plate 12 is illuminated through the through hole 5 formed in the holding case 3. Reference numeral 19 denotes a light shielding member provided so as to cover the light source 17 so that light from the light source 17 does not leak to the outside. Reference numeral 20 denotes an enlargement lens for enlarging an image on the liquid crystal display panel 15. Further, in the lower holding case 1 and the upper holding case 3, convex light shielding walls 22 and 23 are formed so that light rays from the liquid crystal display panel 15 are reflected on the side surface of the holding case and do not reach the observer's eyes 21. The light shielding walls 22 and 23 are desirably cut in a triangular shape at the tip in order to minimize the reflection. When the upper holding case 3 is placed and fixed on the lower holding case 1, the inside of the holding case is sealed, so that foreign matter is prevented from adhering to the liquid crystal display panel 15. The inclined side surface 1a becomes a surface for reflecting the light projected from the light source by using a reflective material for the holding case.
1 may be abolished. The fifth engaging projections 4a formed on the upper holding case 3 not only hold the leading end of the light guide plate 12, but also serve to efficiently project light from the light source 17 to the light guide plate 12. I have. As described above, according to the present embodiment, the components constituting the side light type backlight light source such as the light guide plate 12 and the liquid crystal display panel 15 can be directly incorporated into the same holding case, so that the configuration of the display device is achieved. Can be simplified.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view when the projection direction of the backlight light source is arranged in a direction perpendicular to the light guide plate, and portions similar to those in the above-described embodiment are denoted by the same reference numerals. The backlight light source is configured by refracting light projected from the circuit board 18 fixed to the outside of the side wall of the lower holding case 1 in the direction of the light guide plate 12 by the reflecting plate 30 provided in the upper holding case 3. You. In addition, by using a reflective material for the holding case, the above-described reflective plate 30 can be eliminated by using the inclined surface as a reflective surface. The configuration of the holding case may be a vertical division shown in FIG. 1 or a horizontal division.
The number of divided blocks may be one, or a configuration including a plurality of divided blocks may be used. Thus, the degree of freedom of the configuration of the display device can be further increased.

[0017]

As described above, according to the liquid crystal display device of the present invention, the backlight device, which has been conventionally incorporated in the metal holding frame, is taken into the holding case for holding the liquid crystal display panel. Thus, the configuration of the sidelight type backlight can be simplified.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a display device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the display device according to the embodiment.

FIG. 3 is a sectional view of a display device according to another embodiment of the present invention.

FIG. 4 is an external perspective view of a conventional general viewfinder.

FIG. 5 is a sectional view showing a basic configuration of a conventional viewfinder.

FIG. 6 is an exploded perspective view showing a sidelight type backlight light source using a light guide plate with a conventional light emitting element as a light source.

[Description of Signs] 1 Lower holding case 1a Side surface 2a First engaging protrusion 2b Second engaging protrusion 2c Third engaging protrusion 2d Fourth engaging protrusion 3 Upper holding case 4a Fifth engaging protrusion 4b Sixth engagement protrusion 4c Seventh engagement protrusion 4d Eighth engagement protrusion 5 Through hole 11 Reflector 12 Light guide plate 13 Optical sheet 14 Buffer material 15 Liquid crystal display panel 16 Light transmissive material 17 Light source 18 Circuit board Reference Signs List 19 light shielding material 20 magnifying lens 21 observer's eye 22, 23 light shielding wall 30 reflector 40 body 41 holding frame 50 eyepiece ring 52 backlight 70 metal holding frame 74 optical sheets

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H089 HA40 QA11 TA07 TA16 TA17 TA18 TA20 2H091 FA14Z FA23Z FA41Z FA50X LA11 5G435 AA17 BB12 BB15 EE02 EE27 FF03 FF08 GG23 GG26 KK03 LL14

Claims (11)

[Claims] 1. A liquid crystal display device that irradiates light from a side light type light source to a rear surface of a liquid crystal display panel via a light guide plate, wherein both the light guide plate and the liquid crystal display panel are directly held in the same holding case. A liquid crystal display device characterized by the above-mentioned. 2. The position of the light guide plate and the liquid crystal display panel in the holding case is regulated by engagement projections formed integrally with the holding case. Liquid crystal display device. 3. The holding case comprises a box-shaped lower holding case having one side surface and an upper surface opened respectively, and an upper holding case covering the upper surface opening of the lower holding case. The liquid crystal display device according to claim 1, wherein a side wall facing the formed side surface is formed in a shape along the shape of the light guide plate. 4. The liquid crystal display device according to claim 1, wherein the light guide plate is pressed and fixed to a side wall facing an open side surface of the lower holding case via a reflection material. 5. The liquid crystal display device according to claim 3, wherein an open side surface of the holding case is sealed with a light transmissive material. 6. A light source is arranged in the upper holding case at a position where the light guide plate is irradiated when the upper holding case is arranged at a predetermined position covering the upper surface opening of the lower holding case. The liquid crystal display device according to claim 3, wherein: 7. The liquid crystal display device according to claim 3, wherein a driving circuit for driving the liquid crystal display panel is provided in the upper holding case. 8. The liquid crystal display device according to claim 3, wherein said upper holding case is also provided with an engagement projection for regulating positions of said light guide plate and said liquid crystal display panel. 9. A light shielding wall for preventing light emitted from the liquid crystal display panel from being reflected by an inner wall of the holding case and reaching the eyes of an observer, the upper holding case and the lower holding case being integrally formed. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed. 10. The liquid crystal display device according to claim 3, wherein a reflective material is used on a side wall of the lower holding case facing the open side surface to reflect light. 11. Reflecting light from a light source provided on a circuit board fixed outside a side wall of the lower holding case,
4. The liquid crystal display device according to claim 3, wherein a reflection plate for irradiating the light guide plate is provided on the upper holding case.