JPH0416825A - Optical shutter array - Google Patents

Abstract

PURPOSE:To increase the quantity of transmitted light by providing microlenses which converge parallel light on an optical modulation part on the incidence side of light for respective picture elements and microlenses which make diverged light into parallel light on the projection side. CONSTITUTION:The light is converged by the microlenses 16 of a microlens array 14 corresponding to the respective picture elements on the optical modulation part which is driven by the liquid crystal driving element 9 and transparent electrode 11 of a liquid crystal cell 10 sandwiched between glass substrates 12 and 13, and light which is modulated by an optical shutter 5 is diverged light, so the microlens array 15 provided on the projection side makes the diverged light into the parallel light 2 in picture element units. Namely, light is converged and modulated by each optical shutter 5 and the diverged light is made into the parallel light. Thus, the definition is made high and even when the area of the optical modulation part becomes small as compared with the picture element pitch, the optical shutter array which has high transmissivity and is bright is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides optical gloss for matrix liquid crystal panels, etc.
This invention relates to optical shutter arrays used in projection display devices and the like.

[Summary of the invention]

The present invention realizes an optical shutter array that can form a bright image with little loss of incident light and little temperature rise in an optical shutter array used in a projection display device or the like.

[Conventional technology]

2U! is an example of a conventional optical shutter array that functions as a light modulator and is composed of liquid crystal cells in which pixels are arranged in a matrix. Jfa+, (shown in bl). Figure 2 (al is a diagram showing the configuration of the optical system of a projection display device using a conventional optical shutter array, Figure 2 fb) shows one pixel of the conventional optical shutter array. It is a figure.The incident light 1 to the optical shutter is parallel light, and the output light 2 is enlarged and projected onto the screen 4 by the projection lens 3.At this time, the optical shutter array 5 is an active matrix type liquid crystal cell. Usually configured.

Each liquid crystal display has hundreds of lines arranged in a matrix in the vertical and horizontal directions, each corresponding to the number of scanning lines of the TV.

In order to obtain high display quality, an active matrix type shutter array in which each pixel is provided with a thin film transistor 6 as a switching element is generally used. Each pixel includes a thin film transistor 6, which is a switching element, and a gate electrode 7, which is used for addressing the pixel. It consists of a signal electrode 8 for inputting signals, a transparent electrode 9 for driving the liquid crystal, and the like. The number of pixels provided on each shutter is the number of color pixels projected onto the screen. To increase the resolution of this projection display device, reduce the size of the unit pixel and increase the number of pixels on the shutter, or increase the area of the shutter.
There are methods such as increasing the number of pixels that can be formed on the shutter. In the former method, the resolution of photolithography or the minimum pattern size that can be created in the process is below a certain value (for example, if the minimum line width is 5 microns, the size of a unit pixel is approximately several tens of microns). It is difficult to achieve a minimum pixel size (minimum pixel size), and - for boat fishing, the surface area (aperture ratio) of the portion 9 that modulates the pixel light becomes small as shown in FIG. The latter method is proportional to the number of pixels,
The cost of the shutter and optical components increases as the Noyanotarsa 1z becomes larger. Although it is possible to reduce the pixel size by reducing the area of the part where light modulation is performed, in this case, the amount of transmitted light decreases and the brightness of the screen on the screen 12 decreases.

[Problem to be solved by the invention]

Therefore, this invention was made to solve these drawbacks of the conventional technology.
The present invention provides a projection display device that can provide a bright screen.

[Means to solve the problem]

In order to solve the above problems, the present invention focuses and modulates light for each optical shutter, and then converts the diverging light into parallel light again.

C Effect] By condensing the incident light, all of the incident light passes through the transparent part without passing through the unfavorable bright part of each shutter. After the shutter i3 passes, by making the light parallel again, the transmittance of the optical shutter array for the incident parallel light can be brought close to 100%, and a bright screen can be obtained.

〔Example〕

FIG. 1 (al, ODl shows an embodiment of the present invention. FIG. ial shows the configuration of a projection display device optical system using the optical shutter array of the present invention, and FIG. 2 (b shows an embodiment of the present invention. FIG. 3 is a diagram showing pixels of the optical shutter array of the present invention.The projection display device using the optical shutter array of the present invention is
Similar to the projection display device explained in the figure, parallel light 1 from the light source
■ The liquid crystal drive electrode 9 and the transparent electrode 11 of the liquid crystal cell IO sandwiched between the glass substrate I213 and the individual microlenses 16 corresponding to each of the 14 pixels of the microlens array.
The light is focused on a light modulation section driven by . Each microlens 16 is a convex lens or Fresnel lens formed on a substrate such as plastic or glass, and is realized by forming a spherical or convex surface on the substrate. The focal point distance of each microlens is set to be approximately the distance from the microlens to the optical shutter.

■ The focused light is modulated by a light shutter 5 made of liquid crystal.

(2) Since the modulated light is diverging light, it is converted into parallel light 2 for each pixel by the microlens array 15 provided on the exit side. In this case, the microlens 17 is a convex lens or a Fresnel lens formed on a substrate such as plastic or glass, as described above. The emitted light 2, which has become parallel light, is enlarged and projected onto a screen 4 by a projection lens 3.

If the optical fiber array 5 is made of a field-effect liquid crystal with a 9Q-degree twist, the incident light is normally polarized light, and a polarizing plate serving as an analyzer is provided on the output side as well. The polarizing plate is placed in one place along the path of the incident light. It is sufficient to install it at any one of the J light return paths.

〔Effect of the invention〕

As shown in the above embodiments, according to the present invention C=, even if the area of the light modulation section is made smaller than the pixel pitch due to high definition, a bright light glitter array with a high transmission rate can be realized. Furthermore, since the light absorbed by the glossy array is also reduced, temperature rise can be suppressed, resulting in significant effects such as improved reliability and expanded operating temperature range.

[Brief explanation of drawings]

FIG. 1 (al is a diagram showing the configuration of an optical system of a projection type display device using the optical shutter array of the present invention, FIG. 1 fb) is a diagram showing the cross-sectional structure of a pixel of the optical shutter array of the present invention. , FIG. 2 (al is a diagram showing the configuration of an optical system of a projection type display device using a conventional optical shutter array, and FIG. 2 (bl is a diagram showing the cross-sectional structure of a pixel in a conventional optical shutter array) 1...Incoming light 2...Outgoing light 3...Projection lens 4...Screen 5...Optical shutter array 6...Thin film transistor 7...Gate electrode 8...Signal IT Pole 9...Liquid crystal driving electrode lO...Liquid crystal cell 11...Transparent electrodes 12, 13...Glass substrate 15...Microlens array 17...Microlens applicant Seiko Electronics Co., Ltd. Agent Patent Attorney Keinosuke Hayashi

Claims (1)

[Claims] For each pixel of the optical shutter, which is composed of liquid crystal cells arranged in a matrix, each pixel of the optical shutter has a microlens on the light incidence side that focuses parallel light onto the light modulation section.
An optical shutter array characterized in that each microlens is provided on the output side to convert diverging light into parallel light.