JP3596396B2 - Front light for reflective liquid crystal display device and reflective liquid crystal display device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a front light for a reflection type liquid crystal display device and a reflection type liquid crystal display device.
[0002]
[Prior art]
Liquid crystal display devices are frequently used as small and lightweight display devices. Although used as an electronic viewfinder in a small video camera, a conventionally used liquid crystal viewfinder is a transmission type liquid crystal display device.
[0003]
[Problems to be solved by the invention]
The present invention relates to a reflection-type liquid crystal display device and a front light for the reflection-type liquid crystal display device used therein, and the reflection-type liquid crystal display device must project illumination light onto the liquid crystal display element from the display surface side of the liquid crystal display element. No. SUMMARY OF THE INVENTION An object of the present invention is to prevent dust from entering a front light housing for a reflection type liquid crystal display device and into the reflection type liquid crystal display device, thereby improving the contrast of the reflection type liquid crystal display device.
[0004]
[Means for Solving the Problems]
At least a reflection type liquid crystal display device including a circuit board, a light emitting element mounted on the circuit board and emitting light on the upper surface of the circuit board, and a housing for positioning and fixing a light guide plate, a diffusion member, a polarizing plate, and a transflective sheet. Front light,
The light guide plate is incorporated in the housing so as to be located on the upper surface of the light emitting element, and light from the light emitting element is emitted from the front surface of the inner surface of the light guide plate, and the diffusing member and the polarizing plate are disposed on the light guide plate. Arranged on the front side of the inner surface, emits light parallel to the circuit board from the polarizing plate, and places the semi-transmissive reflection sheet in the housing so that reflected light is incident on the circuit board side in front of the parallel light. Incorporation, a window for viewing the reflective liquid crystal display element in a portion above the transflective reflective sheet of the housing, and a front light for a reflective liquid crystal display device having a transparent film provided on the window. .
[0005]
At least a circuit board, a liquid crystal display element mounted on the circuit board, a light emitting element mounted on the circuit board and emitting light on the upper surface of the circuit board, and a light guide plate, a diffusion member, a polarizing plate, and a transflective sheet are positioned. A reflective liquid crystal display device comprising a housing to be fixed,
The light guide plate is incorporated in the housing so as to be located on the upper surface of the light emitting element, and light is emitted from the light emitting element from the front surface of the inner surface of the light guide plate, and the diffusing member and the polarizing plate are formed of the light guide plate. The semi-transmissive reflection sheet is disposed on the front surface of the inner surface, emits light parallel to the circuit board from the polarizing plate, and the transflective reflection sheet is arranged such that reflected light is incident on the reflection type liquid crystal display element in front of the parallel light. A reflection type liquid crystal display device which is incorporated in a body and has a window for viewing the reflection type liquid crystal display element at a portion above the transflective reflection sheet of the housing, and a transparent film is provided on the window portion. .
[0006]
The transparent film is a polarizing plate having the same polarization characteristics as the polarizing plate provided on the transflective reflection sheet.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
1 is a front sectional view of a front light for a reflection type liquid crystal display device according to the present invention, FIG. 2 is a left side view, FIG. 3 is a right side view, and FIG. 4 is a bottom view. The front light includes a housing 1 having a window 2 for viewing the reflective liquid crystal display element, and a light guide member 3, a diffusion member 4, a polarizing plate 5, a transflective reflective sheet 6, and a transparent member incorporated in the housing 1. It is composed of a film 7.
[0008]
A transparent film 7 is adhered to the inside of the window 2 of the housing 1, and the transflective reflection sheet 6 is incorporated into the steps 8 and the grooves 9, 10 formed inside the housing 1. When the light guide member 3, the diffusion member 4, the polarizing plate 5, and the reflection member 11, which are integrated with the reflection member 11 wrapping the four surfaces of the light guide member 3, which is a rectangular parallelepiped, are incorporated into the concave portion 1 a formed in the housing 1. The front light is completed. A lens sheet may be laminated between the polarizing plate 5 and the diffusion member 4.
[0009]
5 is a front sectional view of a reflection type liquid crystal display device according to the present invention, FIG. 6 is a left side view, and FIG. 7 is a right side view. A reflective liquid crystal completed by mounting a front light on a front light fixing base 14 of a circuit board 12 on which a reflective liquid crystal display element 13, a light emitting element LED 15, and a front light fixing base 14 are mounted at predetermined positions. A display device.
[0010]
FIG. 8 is the same view as FIG. 5 and is a front sectional view of a front light for a reflective liquid crystal display according to the present invention. The reflection type liquid crystal display device is for viewing an image from an eye 16 direction shown in the drawing. Light (arrow (1)) from the light emitting element 15 is introduced into the light guide member 3 from the lower surface of the light guide member 3. The introduced light is diffused by the diffusion member 4 disposed on the front surface of the inner surface of the light guide member 3, and only linearly polarized light (hereinafter referred to as P wave) transmitted through the polarizing plate 5 proceeds in the direction of arrow {circle around (2)}. . The transflective reflection sheet 6 reflects P-waves, and the P-wave reflected by the transflective reflection sheet 6 proceeds to the arrow (3) and enters the transflective liquid crystal display element 13 so as to be transflective. The seat 6 is arranged.
[0011]
The reflection type liquid crystal display element 13 is arranged such that the P wave passes through the liquid crystal as it is when the power is off, and the P wave reflected by the reflection type liquid crystal display element 13 advances in the direction of arrow (4). The polarizing plate 6b of the transflective reflection sheet 6 is arranged so as not to transmit the P wave, and is in a black display state when the power is off.
[0012]
When the power of the reflective liquid crystal display element 13 is turned on, the P wave is polarized by the liquid crystal, and the polarized light that is polarized and reflected by the reflective liquid crystal display element 13 travels in the direction of arrow (4). Since the polarizing plate 6b of the semi-transmissive reflection sheet 6 is arranged so as to transmit the light reflected in the power-on state, it is in the white display state in the power-on state.
[0013]
The polarization direction of the polarizing plate and the arrangement / combination of the reflective liquid crystal display device are appropriately selected depending on the reflective liquid crystal display device.
[0014]
The transparent film 7 is for preventing dust from entering the inside of the housing 1 from the window 2, and can be attached to the outer surface of the housing 1.
[0015]
If a polarizing plate is used instead of a transparent film, the scattered light inside the housing is absorbed, and only the same polarized light as the reflected light from the reflective liquid crystal display element is transmitted by the polarizing plate. , White display is possible, and the contrast can be improved. At this time, it is needless to say that the polarization directions of the transflective reflection sheet and the polarizing plate need to be aligned.
[0016]
【The invention's effect】
Since a transparent film or a polarizing plate is provided on the window of the front light, dust can be prevented from entering the front light and the display surface of the liquid crystal display element.
[0017]
The contrast can be improved by using a polarizing plate instead of the transparent film.
[Brief description of the drawings]
1 is a front sectional view of a front light for a reflection type liquid crystal display device according to the present invention. FIG. 2 is a left side view. FIG. 3 is a right side view. FIG. 4 is a bottom view. FIG. 6 is a left side view. FIG. 7 is a right side view. FIG. 8 is a front sectional view of a front light for a reflective liquid crystal display device according to the present invention.
REFERENCE SIGNS LIST 1 housing 1a recess 2 window 3 light guiding member 4 diffusing member 5 polarizing plate 6 transflective reflecting sheet 6a reflecting plate 6b polarizing plate 7 transparent film 8 step 9 of housing 9 groove 10 groove 11 reflecting member 12 substrate 13 reflection Liquid crystal display element 14 base

Claims (4)

at least,
A circuit board,
A light emitting element mounted on the circuit board and emitting light on the upper surface of the circuit board,
A light guide plate, a diffusion member, a polarizing plate, a housing for positioning and fixing the transflective sheet, a front light for a reflection-type liquid crystal display device,
The light guide plate is incorporated in the housing so as to be located on the upper surface of the light emitting element, and light is emitted from the light emitting element from the front surface of the inner surface of the light guide plate, and the diffusing member and the polarizing plate are formed of the light guide plate. Arranged on the front side of the inner surface, emits light parallel to the circuit board from the polarizing plate, and places the transflective reflection sheet in the housing so that reflected light is incident on the circuit board side in front of the parallel light. A reflection type liquid crystal display device, wherein a window portion for viewing the reflection type liquid crystal display element is provided in an upper part of the transflective reflection sheet of the housing, and a transparent film is provided in the window portion. For front light. at least,
A circuit board,
A liquid crystal display element mounted on the circuit board;
A light emitting element mounted on the circuit board and emitting light on the upper surface of the circuit board,
A light guide plate, a diffusion member, a polarizing plate, a housing for positioning and fixing the transflective sheet, a reflective liquid crystal display device,
The light guide plate is incorporated in the housing so as to be located on the upper surface of the light emitting element, and light is emitted from the light emitting element from the front surface of the inner surface of the light guide plate, and the diffusing member and the polarizing plate are formed of the light guide plate. The transflective sheet is disposed on the front surface of the inner surface, emits light parallel to the circuit board from the polarizing plate, and the semi-transmissive reflective sheet is so arranged that reflected light is incident on the reflective liquid crystal display element in front of the parallel light. A reflection type, which is incorporated in a body and has a window for viewing a reflection type liquid crystal display element in a portion of the housing above the transflective reflection sheet, and a transparent film is provided on the window. Liquid crystal display. 2. The front light for a reflection type liquid crystal display device according to claim 1, wherein the transparent film is a polarizing plate. The reflective liquid crystal display device according to claim 2, wherein the transparent film is a polarizing plate.

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