JP3293602B2 - Reflective liquid crystal display device using optical function element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention uses an optical functional element
And a method of manufacturing the liquid crystal display device .

[0002]

2. Description of the Related Art Liquid crystal displays, which are representative of light receiving type display elements, include a transmission type in which a backlight is placed behind, and a reflection type in which a reflection plate is placed behind and external light is illuminated.

Since the liquid crystal can be driven by a low voltage of several volts, the reflection type liquid crystal element consumes very low power. In a reflection type liquid crystal, an aluminum or silver scattering reflection plate is arranged behind the liquid crystal layer on the back surface. In a black and white reflection type liquid crystal such as a wristwatch, a scattering reflection plate with a polarizing plate is stuck outside the glass.

Conventionally, irregularities 31 as shown in FIG. 3 are formed on a substrate 30 with a molten resist or the like, and a metal reflection film such as aluminum is formed thereon to form a scattering reflection plate 32. As described above, the parallel light is reflected on the scattering reflector 32 by the arrows 33 to 3.
When the light is incident as shown in FIG. 5, the reflected light is scattered as shown by arrows 33 to 35, but the reflected light is distributed with respect to the incident light, centering on the arrow 34 which is substantially in the regular reflection direction. When the scattered incident angle changes, the center of the distribution of the outgoing angle also changes.

FIG. 4 is a distribution diagram showing a distribution of light emitted from the scattering reflector. The vertical axis is the output light intensity, the horizontal axis is the output angle,
When the incident angle is -20 degrees, the emitted light distribution is 41, and the distribution is centered on the regular reflection direction of 20 degrees, but the incident angle is -45 degrees.
When it reaches the degree, the emitted light distribution moves substantially in parallel as indicated by 42 and distributes around 45 degrees.

As described above, in the conventional reflector, when the incident angle changes, the center of the distribution of the emitted light also moves. In reflective LCDs, light enters from various angles, such as ceiling illumination and reflection from walls.With conventional reflectors, illumination near the specular direction mainly reaches the observer. The contribution of illumination incident from the direction is small. A method is also disclosed in which the center of the emitted light distribution is shifted from the specular reflection direction to prevent the illumination from being reflected, but even in this case, if the incident angle changes, the center of the emitted light distribution basically moves. Does not change to

[0007]

A conventional reflection type liquid crystal using a reflection plate, especially a reflection type color liquid crystal using a color filter, has a low transmittance, so that a liquid crystal panel is arranged in the direction of illumination so that it looks dark and bright. There is a problem that it is difficult to see unless the angles are adjusted.

A first reflection type liquid crystal display device according to the present invention for solving the above-mentioned problems comprises a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and one of the pair of substrates. Provided with an optical functional element provided, the optical functional element is arranged in an array, and a light-collecting element for collecting incident light, and a light-collecting element arranged in an array and collected by the light-collecting element. A deflection element comprising a curved mirror whose radius of curvature is greater than the radius of curvature of the microlens and changes the direction of the light, and the light condensing position of the light condensed by the light condensing element differs depending on the incident angle of the incident light, By changing the deflection angle of the deflecting element according to the incident angle of the light condensed on the deflecting element, the outgoing angles for the incident light from various directions are collected in a predetermined direction. A second reflective liquid crystal display device according to the present invention that solves the above problems includes a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and an optical function element. A light-collecting element comprising microlenses arranged in an array for condensing incident light on one of the substrates is provided, and the light-collecting element is arranged in an array so as to be substantially parallel to the light-collecting element. The direction of the light condensed by the optical element is changed, and a deflection element consisting of a curved mirror whose radius of curvature is larger than the radius of curvature of the microlens is provided on the other substrate, and condensed by the condensing element according to the incident angle of the incident light. The converging position of the collected light is different, and the deflection angle of the deflecting element is made different according to the incident angle of the light condensed on the deflecting element, so that the outgoing angle with respect to the incident light from various directions is in a predetermined direction. Characterized by gathering A method of manufacturing a reflection type liquid crystal display device according to the present invention that solves the above-mentioned problem is to provide a curved mirror arranged in an array by providing a curved projection on one substrate and then providing a reflection film on the projection. Then, apply a molten resist on the curved mirror, form a projection pattern just above the curved mirror, and melt the resist to form an array so that it is almost parallel to the light-collecting element. The liquid crystal is interposed between the microlenses and the other substrate after the microlenses are arranged and the radius of curvature is smaller than the radius of curvature of the curved mirror.

[0009]

(Embodiment) A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a sectional view for explaining one embodiment of a liquid crystal element according to the present invention. TFT on substrate 1
The silicon dioxide film 3 covering the array 2 is etched with dilute hydrofluoric acid through a resist with a fine hole to form a concave lens-shaped depression, and an aluminum film 5 is formed thereon.
The curved mirrors 6 were arranged in an array. The diameter of the mirror is 5 microns and the radius of curvature is 6 microns. A melt resist for forming a microlens was applied, and after patterning, it was melted by heating to form a convex lens 7 directly above the curved mirror 6. The radius of curvature of the convex lens 7 is 3 microns.
The refractive index of the resist constituting the convex lens is 1.67.

On top of this, an acrylic resist 8 having a refractive index of 1.42 is applied and smoothed, an ITO film 9 is formed by sputtering, connected to a TFT, and an I
The TO was etched. One such substrate 1 and I
A counter substrate 11 provided with a common electrode 10 of TO was bonded to each surface after an alignment treatment, and a liquid crystal 12 was injected to form a liquid crystal element 13.

When the obliquely incident light 14 enters the liquid crystal element, the light condensed by the convex lens 7 impinges on the inclined portion of the curved mirror 6, and the emitted light 15 becomes diffused light. Is deflected to On the other hand, the front light 16 entering from the front of the panel is condensed by the convex lens 7 at the center of the curved mirror, and the emitted light 17 is also diffused light, but the main emission direction is also the front.

[0013] Incident angle of incident light (angle with respect to the substrate normal)
Becomes larger, the light condensed by the convex lens hits the end of the curved mirror with a larger inclination, and the deflection angle becomes larger.

FIG. 2 shows a convex lens 7 and a curved mirror 6.
FIG. Since the incident light from the illumination is almost parallel light, it is shown by a solid line 18, a dotted line 19, and an alternate long and short dash line 20. The incident light is a solid line 1 passing through the center 21 of the curved surface of the convex lens.
8 and strikes the mirror. Since the radius of curvature of the curved mirror is twice that of the convex lens, the incident light of the solid line 18 is
It is almost reflected to the front. The light indicated by the dotted line 19 and the dashed line 20 is diffused to both sides of the solid line 18 and emitted. Thus, by combining the convex lens and the curved mirror and increasing the curvature of the curved mirror from the curvature of the convex lens,
The emission direction can be substantially aligned with the front direction. Even if the emission direction is not exactly aligned with the front direction due to the aberration of the lens, the distribution of the emission direction of the illumination light incident from all directions is collected in the observation direction.

As described above, in the liquid crystal element of the present invention, it is possible to collect incident light from widely distributed illumination in the front direction, which is the observation direction, and adjust the orientation of the panel to the illumination as in the related art. A display that is less complicated and brighter than the conventional example can be realized.

When a resin lens is formed in a liquid crystal element, the relationship between the curvature of the curved mirror and the curvature of the convex lens is preferably about twice or slightly more than twice that of the present embodiment. When the focal length of the convex lens becomes short, for example, when the convex lens is in contact with the lens, the positional relationship between the curved mirror and the convex lens should be changed, and the present invention is not limited to the numerical values of the present embodiment. Also, both the lens and the mirror need not be formed on one substrate, but the lens may be provided on the counter substrate side. Further, the lens is not limited to the convex lens, but may be a lens using a chirped diffraction grating.

In this embodiment, a reflective liquid crystal which is particularly effective has been described. However, a transmissive liquid crystal using a backlight can also be used. In this case, it is possible to condense the backlight using a concave mirror as a light condensing element, deflect the light by a prism, and align the emission directions.

The combination of the light-condensing element and the deflecting element used in the liquid crystal element of the present invention is an optical functional element that is effective as a means for aligning the direction of the light emission angle in addition to the liquid crystal element.
A display such as a printed matter or an object using this instead of paper can be considered.

[0019]

According to the liquid crystal display device of the present invention, incident light incident from various angles can be collected in a fixed outgoing direction. Thereby, a bright and easy-to-use reflective liquid crystal panel can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal element according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a liquid crystal element and an optical functional element according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional reflector.

FIG. 4 is a diagram showing scattering characteristics of a conventional reflector.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 TFT array 3 silicon dioxide film 5 aluminum film 6 curved mirror 7 convex lens 8 resist 9 ITO film 10 common electrode 11 counter substrate 12 liquid crystal 13 liquid crystal element 14 incident light 15, 17 outgoing light 16 front light

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-211329 (JP, A) JP-A-7-72478 (JP, A) JP-A-6-265702 (JP, A) JP-A-7-724 5464 (JP, A) JP-A-10-333131 (JP, A) JP-A-11-2807 (JP, A) JP-A-5-66720 (JP, A) JP-A-8-241051 (JP, A) WO 96/16348 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1335 G02F 1/1343 G09F 13/16

Claims (3)

(57) [Claims] 1. A pair of substrates, sandwiched between the pair of substrates.
Liquid crystal layer, on one of the pair of substrates
-Type liquid crystal display device provided with an optical function element provided in the device
A is, the optical functional element is made of a microlens are arranged in an array, input
A condensing element for condensing the emitted light, and an array arranged so as to be substantially parallel to the condensing element.
When the direction of the light collected by the light collecting element is changed,
Both have a radius of curvature larger than the radius of curvature of the microlens
A deflecting element comprising a curved mirror, which is focused by the focusing element according to the incident angle of the incident light.
The light condensing position is different, and the deflection angle of the deflection element is deflected.
To make it different according to the incident angle of the light collected on the element
From various directions incident from the other substrate side
The emission angle for light is collected in a predetermined direction.
Reflective liquid crystal display device. 2. A method according to claim 1 , wherein said pair of substrates are sandwiched between said pair of substrates.
Reflective liquid crystal display device having a liquid crystal layer
A location, the optical functional element, light converging incident light on one substrate of the pair of substrates
Light collection consisting of micro lenses arranged in an array
Devices, and arranged in an array so as to be substantially parallel to the light-collecting device.
When the direction of the light collected by the light collecting element is changed,
Both have a radius of curvature larger than the radius of curvature of the microlens
Deflection element consisting of a curved mirror on the other substrate
Then, the light was collected by the light collecting element according to the incident angle of the incident light.
The light condensing position is different, and the deflection angle of the deflection element is deflected.
To make it different according to the incident angle of the light collected on the element
From various directions incident from the other substrate side
The emission angle for light is collected in a predetermined direction.
Reflective liquid crystal display device . 3. After providing the music planar projections on one substrate, arranged in an array by providing a reflection film on the protrusion
Forming a curved mirror, further applying a melt-type resist on the curved mirror, forming a projection pattern directly above the curved mirror, and then melting the resist.
To form an array so that it is almost parallel to the light-collecting element
Are arranged and the radius of curvature is smaller than the radius of curvature of the curved mirror.
After forming the Saima microlenses, manufacturing method of the reflection-type liquid crystal display device characterized by sandwiching a liquid crystal between the other substrate.