JPS60165622A - Transmission type display element - Google Patents

Abstract

PURPOSE:To obtain a display of a bright image plane by providing a light condensing body having a micro-arrangement on the rear of a supporting substrate of a transmission type and photodetection type display element and condensing the incident light from the rear of the substrate to each picture element. CONSTITUTION:A light condensing body made of acrylic, etc. having a semicircular cylindrical micro-lens array 11 is provided on the surface of an element of a photodetection type and transmission type such as liquid crystal display, electrochromic display or the like on the side opposite to the surface provided with a thin film transistor 2, a drain electrode 3 and a gate electrode (display electrode) 5 on one transparent substrate 1. The rays 20, 21, 22 made incident on the lens array body 11 are concentrated through the substrate 1 on a display aperture part 12, i.e., display electrode 5. The display image of, for example, the display element which is provided with a common electrode 7 and a color filter 8 on a counter substrate 6 and is sealed therein with a liquid crystal 10 is displayed brightly. The lens arrangement may be an array consisting of spherical lenses or a lens array made into a V-shaped groove type or trapezoidal shape.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a transmissive type light-receiving display element capable of displaying a bright screen.

(Prior Art) Currently, the CRT (CGTHOD Ray Tube) is used as a display device for displaying characters, graphics, television images, etc.
, cathode ray tubes) are mainly used, but CRTs have the disadvantage of being bulky, and various thin display devices have been proposed to replace them, and some have been put into practical use. These display elements can be classified into light-emitting and light-receiving types. Light-emitting buttons include plasma displays, fluorescent display tubes, electroluminescent displays, light-emitting diode displays, etc., and light-receiving buttons include liquid crystal displays and electrochromic buttons. Displays, electrophoretic displays, electro-optic crystal displays, etc. Each of these thin display elements has its own advantages and disadvantages, but in general, light-emitting display elements provide a bright display but require a high driving voltage.
On the other hand, although light-receiving display elements generally consume less power, they have the disadvantage that the display is difficult to see in dark places because they are light-receiving types that do not emit light themselves. There is. For this reason, light-receiving display elements are designed to incorporate a reflective structure to capture a large amount of ambient light, but even so, the display is hardly visible under weak ambient light. Therefore, in many cases, a light-receiving display element is provided with an illumination light source behind it. However, when a light source for illumination is provided, its power consumption is large, and the advantage of low power consumption of the light-receiving display element is lost. Therefore, in order to reduce power consumption as much as possible and obtain display brightness comparable to that of light-emitting display elements, K is to use the incident light from the illumination light source as effectively as possible for display in transmissive display elements. is essential. Conventionally, as a means of achieving this, for example, a fluorescent light is irradiated from the edge of a transparent substrate of a liquid crystal display element, and the incident light from the fluorescent light is repeatedly reflected inside the transparent substrate and effectively illuminates the entire display surface. was taken. (Proceedings of the 3rd Liquid Crystal Symposium, p. 24, 1977) However, even with these efforts, light-receiving display elements still cannot provide sufficiently bright displays with low power consumption. This is the current situation. For example, an active matrix type liquid crystal display element (3) with a built-in color filter, which is attracting attention as a thin display element with a large display capacity comparable to CRTKs and the possibility of color display, has a luminance of 400 nits at 4W. Even with a standard light source, only 20 nits of brightness can be obtained on the display screen, which is inferior to a 1.5-inch color CRT that consumes 4W and has a power consumption of 10 nits. However, the present inventors have devised a light-receiving type display element with a novel structure that can effectively utilize ambient light or incident light from an illumination light source for display, resulting in the present invention.

(Object of the Invention) An object of the present invention is to provide a light-receiving display element capable of displaying a bright screen.

(Structure of the Invention) The transmissive display element of the present invention uses at least one transparent body as a support substrate for a display substance, and performs display by controlling incident light from behind the support substrate by the display substance. It is a transmission type display element, and is characterized in that a light condenser having a microlens array is placed on the back side of the support substrate.

(4)- (Example 1) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing the structure of one supporting substrate used in an embodiment KK of a transmissive display element of the present invention. In Fig. 1, 1 is a glass substrate with a thickness of 1.1 mm, and 2 is a TPT (Th1n Fit) made of amorphous silicon.
3 is an Mo drain electrode, 4 is an MO gate electrode, and 5 is an indium oxide pixel electrode (transparent electrode).

Although not clearly shown in the figure, the intersection of the drain electrode 3 and the gate electrode 4 is isolated by a silicon dioxide insulating film. FIG. 2 is a schematic diagram showing the structure of an embodiment of the transmissive display element of the present invention formed using the support substrate shown in FIG. FIG. In FIG. 2, 1 is the glass substrate of FIG. 1, and 2, 3, and 5 are TPTs formed on the glass substrate 1, respectively.

These are the drain electrode and the pixel electrode. 6 is the same thickness as 1
．． It is a 1 mm 2 glass substrate, on which are provided an indium oxide common electrode 7 formed over the entire surface and a dot-shaped color filter 8 formed at a position corresponding to the pixel electrode 5. Three types of color filters 8, red, blue, and green, are arranged alternately. Two glass substrates 1 and 6 are adhesively fixed around the periphery with an epoxy adhesive 9, and the gap between them is filled with a liquid crystal material 10 containing a black dichroic dye, forming a so-called guest-host active matrix. It constitutes a liquid crystal display element with a built-in color filter. Further, on the back side of the glass substrate 1, an acrylic light condenser 11 having a "cylindrical-shaped" microlens array is placed side by side.

In this embodiment, the liquid crystal material is the display material, and the transparent bodies serving as supporting substrates for the display material are two glass substrates. The liquid crystal material is the gate electrode 4. Drain electrode 3. Depending on the voltage waveform selectively applied to the common electrode 7, a well-known guest-host type electro-optic effect is exhibited. That is, on the "on pixel" almost all incident light from behind the glass substrate 1 is transmitted, and on the "off pixel" almost all incident light from behind the glass substrate 1 is absorbed and not transmitted.

The transmitted light appears to be colored by the color filter formed corresponding to each pixel electrode, so in the end, red and red on a black background appear.
Color display using blue, green, and a mixture thereof is realized.

(Actions and Effects of the Invention) Here, the effect of the condenser 11 having a microlens array will be described as a third effect.
This will be explained using figures. FIG. 3 is a diagram depicting a portion of the glass substrate 1 and the condenser 11 in FIG. 2 to approximately exact scale, and 12 is a state in which the liquid crystal material transmits incident light on the "on pixel". , which indicates the area of the so-called opening. That is, as shown in FIG. 1, the incident light is controlled by the electro-optic effect of the guest-host type liquid crystal material.
The so-called pixel region is only the region of the pixel electrode 5 in FIG. 1, and the other regions are always in a state of blocking incident light. In this embodiment, the area occupied by the pixel electrode in FIG. 1 is about 60% of the total area, and the length of the opening 12 in FIG. 3 is 180 μm, and the interval between the openings is 70 μm. In FIG. 3, of the incident light from behind the glass substrate 1, 20 light beams (7) travel straight through the opening 12 and effectively contribute to the display. Further, the incident light that takes the optical path 21 or 22 is refracted by the microlens array formed on the back surface of the condenser 11, passes through the aperture 12, and effectively contributes to display. That is, in the transmissive display element of this embodiment, all incident light passes through the aperture 12 within the plane of FIG. 3 and effectively contributes to display. however,
In the conventional structure without the condenser 11, as shown by the broken line in FIG. 3, the incident light 21.22 also travels straight as 31.32, reaches the non-aperture, and does not contribute to the display. In this example, when an illumination light source with a brightness of 400 nits is installed behind the light condenser 11, a display brightness of 28 nits is obtained, and when no light condenser is installed, the display brightness is 200 nits.
A noticeable improvement was seen compared to the Nitsuto, and a brighter screen display was realized. Of course, even when no special illumination light source was installed, the transmissive display element of this example provided a brighter screen display than that of the conventional structure. In addition, in this example, since a collection of semi-cylindrical microlens arrays (phase light body) was used, the direction parallel to the semi-cylindrical lenses (the first
Although the light focusing effect on the aperture ratio in the direction perpendicular to AA' within the plane of the figure could not be obtained, the effect was further improved by making the microlens array a hemispherical microlens arrangement, and this example The display brightness of 28 nits is improved by I/C1 by about 33 nits.

(Embodiments 2 and 3) FIGS. 4 and 5 are cross-sectional views showing the shape of a condenser having a microlens array in other embodiments of the present invention, and the one in FIG. "Shape", Figure 5 1
It is a trapezoidal microlens. Even in these embodiments, the same effect as the "semi-cylindrical" microlens shown in Fig. 2 can be obtained, and a brighter screen display can be obtained than with the conventionally structured transmissive display element. Ta. In addition,
In the above embodiments, the case of a so-called active matrix type liquid crystal display element with a built-in color filter has been described.
← n 4 % v no -ep near-1= 紫ζ,
, 1 Nomi Fuichi'-W & W no'J Uno' Akebono-Nonosaku mode is not limited to the guest host type.
However, in an active matrix method in which a switching element is connected to each pixel to operate a display material such as a liquid crystal material, the effect of the present invention is extremely pronounced because the switching element significantly reduces the aperture ratio of the display screen. . Furthermore, even in a liquid crystal display element having a structure in which a color filter array is installed at a position corresponding to each pixel, the color filter selects the incident light in terms of wavelength and significantly reduces the amount of transmitted light, that is, the brightness, so the present invention is effective. is extremely pronounced.

(Example 4) FIG. 6 shows an example in which an ELECTRIC μmic material is used as the display material. In this case, only one support substrate may be used. The figure shows one example, 41 is a glass substrate, 42 is a polysilicon T-43 is a Mo drain electrode,
45 is a tin oxide pixel electrode, 50 is an ichtungsten oxide layer as a display material, 52 is magnesium fluoride m as an ion conductive layer, 47 is a tin oxide common electrode, and 51 is a "semi-cylindrical shape" provided behind the glass substrate 41. This is an acrylic light condenser with a microlens array. In this example, the same effects as in the above-mentioned example were obtained.

The display material may be a material other than those shown in the above examples, for example, a known electrochromic material, an electro-optic crystal represented by a material known by the name PLZT, or a material such as garnet. It goes without saying that the present invention is also effective when a magneto-optic crystal or the like is used.

As described above, according to the present invention, a light-receiving display element capable of displaying a bright screen can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of one supporting substrate in an embodiment of the present invention, in which 1 is a glass substrate, 2 is a thin film transistor, 3 is a drain electrode, 4 is a gate electrode, and 5 is a pixel electrode. FIG. 2 is a cross-sectional view showing the structure of an embodiment of the present invention using the support substrate shown in FIG. 1, in which 1, 2, 3, and 5 are the same as in FIG. A counter electrode, 8 a color filter, 9 an adhesive, 10 a display material, and 11 a light condenser having a microlens array. FIG. 3 is a diagram for explaining the effect of the embodiment of FIG. 2, and 1.11 is a diagram of the second embodiment.
Same as the figure, 12 is the display aperture, 20.21.22 is the optical path of the incident light, 31.32 is the condenser 1 shown for comparison.
1 is the optical path of the incident light in a conventional structure without 1. 4 and 5 are cross-sectional views of a condenser having a microlens array used in another embodiment of the present invention. FIG. 6 is a diagram showing an example in which an electrochromic material is used as the display material. Sengo Patent Attorney Shinsai Mukami 1 Kusai 3 Zusen 6 Leap 1 Wawa

Claims (1)

[Claims] A system comprising a supporting substrate made of at least one transparent body or a plurality of transparent bodies and a bottom indicator material supported by the supporting substrate, and displaying by controlling incident light from the back of the supporting substrate with the display material. 1. A transmissive display element characterized in that a light condenser having a microlens array is disposed on the back surface of the support substrate.