JPH0743740A - Optical active matrix display - Google Patents

Abstract

PURPOSE:To easily input an address light to each optical waveguide of optical active matrix, to constitute the device so that the number of parts is extremely few and manufacturing cost is inexpensive, not to be affected so much by mechanical variation, and to improve stability of operation. CONSTITUTION:Many optical waveguides of an optical waveguide array substrate 10 are formed so that their end planes can be seen through a transparent substrate. The direction of a light beam emitted from a laser optical system 20 is varied by a rotary polygon mirror 22, an angle of a reflected light beam is varied by a telecentric optical system 28 consisting of a toric lens, the light beam is made incident on an end plane of the light waveguide independently of the scanning direction. A lens array 30 in which convex lenses 32 are arranged is preferably provided at positions corresponding to each light waveguide at end planes of light waveguides in optical active matrix. Interlace scanning also can be performed by using the lens array provided with lens groups of an odd side and an even side at the upper and the lower part and two light beams.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical active matrix display using an optical scanning device having a rotary polygon mirror. This is a technology particularly suitable for a large area liquid crystal display, and for example, various AV equipment, O
It can be widely used for A equipment.

[0002]

2. Description of the Related Art Active matrix drive liquid crystal displays are becoming the mainstream of liquid crystal displays because of their high display quality. And such a display device,
With the demand for large capacity, the number of picture elements is 400 × 600 to 1000 ×
It is required to increase to 1000 or more, and the display screen size is also required to be larger from 10 inch (254 mm) diagonal to 20 inch (508 mm) diagonal or more. There is.

However, a thin film transistor (TFT) that constitutes an active matrix has a complicated manufacturing process, and defects are likely to occur mainly in an overlapping portion of wirings, so that the yield is low and it is difficult to reduce the cost. There is. The solution to this problem is to increase the number of picture elements,
It becomes more difficult as the display screen size increases. Further, when the display screen size is increased, the length of the wiring becomes longer, the wiring resistance increases accordingly, and there is a problem that the signal waveform is delayed due to the wiring resistance and the stray capacitance.

As a technique capable of solving such a problem,
An optical active matrix shown in FIGS. 10 and 11 has been proposed (JP-A-1-173016, etc.). This is because a large number of parallel optical waveguides 102 are formed in a glass substrate 101.
And a large number of photoconductive materials 103 are disposed on the optical waveguide 102 so as to be in contact with the light path lacking the cladding portion, and a part of the light passing through the optical waveguide 102 is formed on the photoconductive material 103. It is configured to be incident on 103. Each photoconductive material 103 controls ON / OFF between the metal thin film line 104 and the metal thin film line 105, and these constitute the optical switch element 106. The metal thin film line 105 is used for each pixel electrode 107 that forms a pixel for liquid crystal display.
And an electric signal of an image for liquid crystal display is applied to the other metal thin film line 104, and the optical switch element 10 is connected.
An electric signal of the image is applied to the picture element electrode 107 via 6.

In FIG. 11, the metal thin film line 104 is formed in the horizontal direction, and the optical waveguide 102 is formed in the vertical direction.
When light enters the optical waveguide 102, the optical waveguide 102
The upper optical switch element 106 is turned on, and the electric signal carried on the metal thin film line 104 is applied to the picture element electrode 107 to control the orientation of the liquid crystal. For example, assuming that light sequentially enters from the optical waveguide 102 at the left end in FIG. 11, and the light now passes through the optical waveguide 102 at the left end, all the optical switch elements 10 provided on this optical waveguide 102.
6 is turned on, and the optical switch elements 1 in the other columns are
06 is an off state. At that time, if an image signal (electrical signal corresponding to picture element information) is applied to the metal thin film line 104, the electric signal is applied to the picture element electrode 107 in the left column of FIG. 11 to control the alignment of the internal liquid crystal. . The same applies to the right column, and by repeating this, image signals are sequentially applied to all the pixel electrodes 107 and the alignment of the liquid crystal is controlled to display an image.

In such an optical active matrix, it is necessary to sequentially enter light into each optical waveguide. Therefore, it has been considered to individually form a light emitting element (for example, a light emitting diode, a laser diode, or an electroluminescent element) for each optical waveguide.

Apart from that, as a conventional technique for scanning light, there is a method of scanning a light beam from a laser, which is a light source, with an optical system such as a rotating polygon mirror, as seen in a laser printer or the like. In the laser printer, as shown in FIG. 12, a single laser beam 120 narrowed down to, for example, about 100 μm is applied to a rotating polygon mirror 121, and the reflected light is condensed on the surface of the photosensitive drum 123 by a converging lens 122. In this way, the laser beam scans the scanning surface of the photosensitive drum 123 as the rotary polygon mirror 121 rotates at high speed.

[0008]

However, if the light emitting element is arranged for each optical waveguide as described above, a normal liquid crystal display requires several hundred or more light emitting elements. Therefore, not only the uniformity of the light emission intensity of each light emitting element becomes a problem, but also its attachment becomes complicated, and the scanning light source is inevitably expensive. Further, since each light emitting element has to be individually controlled in time series, the control circuit becomes complicated.

On the other hand, in the above-described optical scanning system used in a laser printer, the laser light is subjected to light intensity modulation in accordance with desired display information, and the fθ lens used as a converging lens is a photosensitive drum. Although it is used for condensing on the surface, there is a feature that it is not necessary to strictly control the angle of the principal ray incident on the surface of the photosensitive drum. Therefore, even if these conventionally known light sources and optical systems are simply combined with the above-mentioned optical active matrix display, it is impossible to present a uniform display, as will be apparent from the detailed description given later.

A main object of the present invention is to solve the above-mentioned technical problems and to optimize the optical system so that light from a small number of light sources can be easily and effectively addressed to each optical waveguide of the optical active matrix. It is an object of the present invention to provide an optical active matrix display of a rotary polygon mirror scanning system including the above. Another object of the present invention is to provide an optical active matrix display capable of highly efficiently inputting scanned address light to each optical waveguide of the optical active matrix and preventing display crosstalk. is there.

Still another object of the present invention is to easily and separately provide address light to each optical waveguide of odd-numbered columns and optical waveguides of even-numbered columns of an optical active matrix so that an interlaced scanning system by light can be performed. It is to provide an optical active matrix display that can be input.

Another object of the present invention is to provide an optical active matrix display which controls the writing of image information by using a detection output of a light beam as a trigger signal for synchronization of an optical signal and an electric signal. Still another object of the present invention is to control the electric power supplied to the light source so that the intensity of the light beam addressed to each optical waveguide becomes substantially constant, stabilize the characteristics of the optical switch element, and achieve a high-quality display. It is to provide an optical active matrix display that enables the above.

[0013]

According to the present invention, a large number of optical waveguides arranged in one direction in a plane of a transparent substrate, and linear electrodes for applying image signals arranged so as to intersect the optical waveguides are provided. Picture element electrodes arranged in an array for image display,
An array of optical switch elements, which are located near the intersections of the optical waveguides and the linear electrodes and connect the linear electrodes and the pixel electrodes, are provided, and the light passing through the optical waveguides is incident on the optical switch elements. It is premised on an optical active matrix having a configuration in which the optical switch element is changed from an off state to an on state. In order to achieve the above object, in the present invention,
The optical waveguides are formed so that their end faces appear on the transparent substrate, and the light source that emits the light beam, the rotary polygon mirror that changes the direction of the light beam, and the rotary polygon mirror are taken out. The optical scanning device includes a lens system that changes the angle of the light beam so that the light beam is incident on the end face of the optical waveguide regardless of the scanning direction.

Here, the angle θ formed by the chief ray of the light beam incident on each optical waveguide of the transparent substrate with respect to the end face of the transparent substrate is substantially constant (particularly preferably about 90 degrees). Then, design the optical system. Further, a lens array having lenses arranged at positions corresponding to the individual optical waveguides is provided on the end surface of the optical waveguide in the optical active matrix, and the light beam passing through the lens array is focused near the end surface of the optical waveguide. It is preferable to configure. This lens may be a normal convex lens, a Fresnel lens, or the like. Also in this case, the optical system is designed such that the angle θ formed by the principal ray of the light beam incident on each lens of the lens array with respect to the end face of the lens array is substantially constant (almost 90 degrees).

Further, in the present invention, the optical waveguides are formed so that their end faces appear on the transparent substrate.
A light source that emits a light beam of a book, a rotating polygon mirror that changes the direction of the light beam, and an angle of the light beam extracted from the rotating polygon mirror to change the angle of the light beam so that the light beam does not depend on the scanning direction. The optical scanning device includes a lens system that is directed toward the end face of the waveguide, and a lens array that is located at the end face of the optical waveguide and that condenses a light beam near the end face of the optical waveguide.
The lens array is provided with two stages of an odd-numbered lens group in which lenses are arranged at positions corresponding to the respective odd-numbered optical waveguides and an even-side lens group in which lenses are arranged at positions corresponding to the even-numbered optical waveguides. The light beams for scanning the odd-numbered lens groups enter the optical waveguides in the odd columns and the light beams for scanning the lens groups in the even columns alternately enter the optical waveguides in the even columns.

In these, it is preferable that a photodetector is provided at a position on the lens array or the transparent substrate on the light beam scanning start side, and the writing of image information is controlled by using the output from the photodetector as a trigger signal. Further, by providing a photo-detecting element array in which the photo-detecting elements are respectively located on the exit side end faces of the optical waveguides of the optical active matrix, the power supplied to the light source can be controlled so that the photocurrent of each photo-detecting element becomes almost constant. .

[0017]

The direction of the light beam emitted from the light source is well controlled and goes to the rotary polygon mirror. The rotating polygonal mirror continuously changes the direction of reflected light by its rotation and scans the light beam in a fan shape. The light beam is incident on the end face of the optical waveguide of the optical active matrix by the lens system. In that case, the lens system refracts the light beam so as to be substantially perpendicular to the end face of the optical waveguide regardless of the scanning direction. In the present invention, since the end surface of the optical waveguide is configured to appear on the transparent substrate, the light beam enters the end surface of the optical waveguide and enters the optical waveguide. By making the angle between the principal ray of the light beam and the transparent substrate substantially constant, the amount of light entering the optical waveguide becomes constant, and uniform display can be obtained. In particular, if the angle is set to about 90 degrees, high efficiency can be obtained.

Further, when a lens array having lenses corresponding to the respective optical waveguides is provided on the end face of the optical waveguide, the incident light beam is condensed by the respective lenses, thereby improving the light utilization efficiency. Further, the lens array always fulfills the function of condensing the light beam at a fixed point even if the scanning position of the light beam changes due to mechanical fluctuation or the like. As a result, it becomes less susceptible to mechanical or temperature changes, and the operation of the optical active matrix display becomes extremely stable. Furthermore,
Providing a light-shielding layer on the incident side of the light beam to the optical waveguide can prevent display crosstalk.

Further, in the present invention, two light beams are alternately emitted from the light source, one light beam scans the lens groups on the odd side to sequentially enter the optical waveguides in the odd rows, and the other light beam is The even-numbered lens groups are scanned to sequentially enter the optical waveguides of the even-numbered columns. Interlace scanning is realized by the lens array having two kinds of lens groups arranged in two stages in this way.

In the present invention, the output from the photo-detecting element provided at the position on the light beam scanning start side of the lens array or transparent substrate serves as a trigger signal to control the writing of image information. Further, the display quality is improved by controlling the electric power supplied to the light source so that the optical signal of the photo-detecting element array provided on the emission side end face of each optical waveguide of the optical active matrix becomes substantially constant.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram showing an embodiment of an optical active matrix display according to the present invention.
Further, FIG. 2 is a partial explanatory view thereof, showing the state of incidence of a light beam on the optical waveguide.

First, an example of the optical waveguide array substrate 10 used in the optical active matrix display according to the present invention will be described. 3 is a basic configuration diagram, and FIG. 4 is a sectional view taken along line AA. Note that in FIG. 3, the glass substrate, the transparent electrode, the liquid crystal layer, and the sealing material are omitted for clarity. As shown in FIGS. 3 and 4, a plurality of optical waveguides Y ₁ ,
_{Y 2, ..., Y n-} 1, Y n and arranged in the Y direction, a plurality of linear electrodes X ₁ so as to intersect on these, X _2, ..., X
_m-1 and X _m are arranged in the X direction. Optical waveguides Y ₁ , Y ₂ ,
..., Y _n-1 , Y _n and the linear electrodes X ₁ , X ₂ , ..., X _m-1 ,
X _m and the pixel electrode 2 for driving a display medium such as a liquid crystal are formed on the same plane, and linear electrodes X ₁ , X ₂ ,
The optical switch element 1 is positioned so as to connect the pixel electrodes 2 with X _m−1 , X _m . The transparent electrode 3 is provided on the other glass substrate 5b, and both glass substrates 5a and 5b are provided.
The liquid crystal layer 7 is sealed between the sealing material 9 and the sealing material 9. In the present invention, the optical waveguide Y ₁ formed on the glass substrate 5a,
, Y _n are formed such that the end faces of the multiple arrays of the optical waveguides Y ₁ , ..., Y _n appear on the end face of the glass substrate 5a (see FIG. 2).

In the present embodiment, the optical scanning device shown in FIG.
A laser optical system 20, a rotary polygon mirror 22,
It is provided with two reflecting mirrors 24 and 26 and a telecentric optical system (hereinafter, simply referred to as “telecentric optical system”) 28 including a toric lens. Further, as shown in FIGS. 2 and 4, the lens array 30 is installed on the end surface of the optical waveguide array substrate 10. The light beam 40 emitted from the laser optical system 20 is reflected by the rotary polygon mirror 22 rotating at a constant speed by a motor or the like, and the reflected light beam continuously changes (scans) in a fan shape. The direction of scanning is indicated by arrow S. This light beam is reflected by the two reflecting mirrors 24, 2
It is reflected at 6, changes its direction, and enters the telecentric optical system 28. The telecentric optical system 28 refracts the light beam, but performs a function of correcting the refracted and emitted light beam so as to be substantially perpendicular to the end surface of the lens array 30 without depending on scanning. Therefore, the light beam enters the lens array 30 almost vertically from the start to the end of scanning. The lens array 30 is
This incident light is condensed at a predetermined position on the end face of the optical waveguide array substrate 10. Each of the lenses 32 includes an optical waveguide Y ₁ ,
,, Y _n are arranged at positions corresponding to each one.

The optical beam passing through the telecentric optical system 28, as shown in FIG. 2, bent by the convex lens 32 produced in the lens array 30, the optical waveguide Y _1, ..., Y
incident on _n . Each convex lens 32 has a function of condensing the scanned light beam and narrowing it down to a predetermined incident point of the corresponding optical waveguide Y ₁ , ..., Y _n . At that time, the position of the focal point does not change even during the scanning. By providing the lens array 30 in this way, even if the position of the light beam on the incident surface of the optical waveguide fluctuates, the light beam enters a certain converging point, so that there is a mechanical or temperature fluctuation and in terms of accuracy. It is possible to easily avoid problems.

When the light beam 40 enters the optical waveguides Y ₁ , ..., Y _n and irradiates the optical switch element 1, the electrical resistance of the optical switch element 1 is reduced and the image signal from the linear electrode X ₁ is transmitted. It is applied to the picture element electrode 2, which changes the alignment state of the liquid crystal. Therefore, the light beam 40 is directed to the optical waveguide Y ₁
Sequentially scanned to Y _n from the linear electrodes X ₁ an electrical signal in response thereto, ..., is applied to the X _m, light the optical waveguide Y _1, ..., a period in which guided the Y _n, the optical Since the optical switching element 1 on the waveguide is turned on, the electric signals from the linear electrodes X ₁ , ..., X _m are transmitted to the picture element electrodes 2 respectively.
Applied to. That is, the optical waveguide Y ₁ in place of the electric gate signals of the thin film transistor element, ..., the optical signals passing through Y _n, an optical switching element connected to the optical waveguide 1
It will be sequentially switched for each column. As a light source,
In addition to the semiconductor laser, an infrared laser or an ultraviolet laser may be used as long as it has a sensitivity wavelength of the photoconductor layer that is the optical switch element 1.

The optical waveguide array substrate shown in FIG. 3 can be manufactured, for example, as shown in FIG. First, a groove is formed on the glass substrate 5c using a blade. The width of the groove depends on the cladding diameter of the optical fiber Z to be used, but is 5 μm to 500 μm.
It is about m. The pitch of the grooves depends on the size and resolution of the panel, but is preferably 150 μm to 800 μm, and more preferably 300 μm to 600 μm. The cross-sectional shape of the groove is V-shaped here, but the shape of the bottom may be flat or semicircular. The groove processing method may be chemical processing by an etching method. The optical fibers Z are arranged in the formed grooves, the ultraviolet curable resin 11 is applied, another glass substrate 5a is placed, and then ultraviolet rays are irradiated to be cured. In the optical fiber Z, the central core 12 is surrounded by the clad 13,
The light-shielding film 14 covers the outermost periphery. Next, polishing is performed from the glass substrate 5c side, and optical polishing is performed until a part of the light propagating through the optical fiber Z leaks.

The optical waveguides Y ₁ , ..., Y _n and the linear electrodes X ₁ ,
A photoconductor layer to be the optical switch element 1 is formed at the intersection of X _m . This photoconductor layer is formed by forming a hydrogenated amorphous silicon (a-Si: H) film by using a plasma chemical vapor deposition method, and patterning it by etching. As the photoconductor layer, a hydrogenated amorphous silicon germanium (a-SiGe: H) film, a hydrogenated amorphous silicon carbide (a-SiC: H) film, a hydrogenated amorphous silicon oxide (corresponding to the wavelength of a light source to be used is used. a-SiO: H) film, hydrogenated amorphous silicon nitride (a-SiN: H)
A membrane or the like can also be used. Then, the linear electrodes X ₁ , ..., X
_{As m} , aluminum or the like is formed by an electron beam evaporation method and patterned by etching to be formed. In addition to this, a metal such as molybdenum or indium-tin oxide may be used as the linear electrode.

On the other hand, the pixel electrode 2 is formed by depositing indium-tin oxide by sputtering and patterning by etching. An alignment layer 6a is formed on these layers.
The alignment layer 6a is formed by rubbing a polyimide film formed by a spinner. The alignment layer 6a may be formed by a printing method. The transparent electrode 3 is provided on the other glass substrate 5b. The transparent electrode 3 is formed by depositing indium-tin oxide by a sputtering method. This transparent electrode 3
A light-shielding layer 4 is formed on the upper surface of the light-shielding layer 4 so as to match the pattern of the optical switch element 1 formed of a photoconductor layer formed on the opposing glass substrate. The light shielding layer 4 is formed by manufacturing aluminum by an electron beam vapor deposition method and etching it. As the light shielding layer 4, a metal such as molybdenum or an organic or inorganic pigment dispersion resin may be used. Here, the transparent electrode 3
Although formed on the upper surface, it may be formed on the back surface of the glass substrate 5b. Further, an alignment layer 6b is formed on these. This alignment layer 6b is also made by rubbing a polyimide film. Between both glass substrates 5a and 5b on which each layer is formed in this manner,
Spacers (not shown) are dispersed and bonded together with the sealing material 9 interposed therebetween. In the meantime, liquid crystal is vacuum-injected to form the liquid crystal layer 7. The liquid crystal layer 7 has a thickness of about 5 μm, and the display mode is a normally white type of twisted nematic (TN). As the liquid crystal material, for example, a PC manufactured by Merck
There is an H liquid crystal ZLI-1565. The lens array 30 is attached to the liquid crystal panel with the optical waveguide array manufactured as described above.

By the way, as shown in FIGS. 2 and 4, in this embodiment, the convex lens 3 on the incident side end surface of the lens array 30 is used.
A light shielding layer 34 is provided between the two. This is a light beam
When moving from one convex lens to the next convex lens, the light blocking layer 3
This is because without 4 there is a possibility that light will be instantaneously distributed to the two adjacent optical waveguides. Therefore, by providing the light shielding layer 34, the light beams are prevented from entering the two optical waveguides at the same time. For this purpose, the light shielding layer 34 is
Its width must be larger than the diameter of the light beam.
Although the light shielding layer is provided on the lens array 30 here, the present invention is not limited to this, and it may be provided at any effective position between the rotary polygon mirror and the optical waveguide array substrate.
For example, it may be provided between the lens array 30 and the optical waveguide array substrate 10.

Now, such a lens array 30 can be manufactured by, for example, the following ion exchange method. A metal film is formed on a glass substrate containing an alkali such as sodium, and minute openings (holes) are provided therein. By immersing this in a solution containing ions such as thallium, the alkali ions in the glass substrate at the opening of the metal film replace the thallium ions. The portion replaced with this thallium ion has a higher refractive index than the other portions. When the ion exchange time is lengthened, the exchange proceeds one after another, and a region having a hemispherical refractive index rise is formed around the opening of the metal film. This area functions as a convex lens. The place where the lens is formed can be freely controlled by the position of the hole formed in the metal film.

FIG. 6 is an overall configuration diagram showing another embodiment of the optical active matrix display according to the present invention. Further, FIG. 7 is a detailed explanatory view of the lens array, and FIG. 8 is an explanatory view of a coupled state of the optical waveguide array substrate and the lens array, showing an incident state of the light beam on the optical waveguide. The optical waveguide array substrate 10 on which a large number of optical waveguides are formed may basically have the same structure as that shown in FIGS. 3 and 4 described in the above embodiment. Therefore, in order to simplify the description, the detailed description of the optical waveguide array substrate 10 is omitted. However, also in this embodiment, as shown in FIG. 8, the optical waveguide 4 formed on the transparent substrate 42 is formed.
4 is formed so that the end faces of the multiple arrays of the optical waveguides 44 appear on the transparent substrate 42.

The optical scanning device includes a semiconductor laser optical system 50 for emitting two light beams, a rotary polygon mirror 52, two reflecting mirrors 54 and 56, and a telecentric optical system 58.
And a lens array 60. From the semiconductor laser optical system 50, two light beams 70o and 70e on the odd side and the even side are emitted alternately at different timings. Both light beams are reflected by the rotating polygon mirror 52 rotating at a constant speed by a motor or the like, and the light beams continuously change (scan) in a fan shape. The direction of scanning is indicated by arrow S. These light beams are reflected by the two reflecting mirrors 54 and 56, change their directions, and enter the telecentric optical system 58 at vertically different positions. Telecentric optical system 58
Refracts the light beam, and performs a function of correcting the refracted and emitted light beam so as to be substantially perpendicular to the lens array 60 without depending on scanning. So the light beam is
From the start to the end of scanning, the light enters the lens array 60 almost vertically.

In this lens array 60, an odd-numbered lens group in which odd-numbered lenses 62o are arranged at positions corresponding to odd-numbered optical waveguides, and an even-side lens 62e are arranged in positions corresponding to even-numbered optical waveguides. Equipped with an even number side lens group,
They are provided in upper and lower two stages. The details are as shown in FIG. Here, A is a plan view and B is its xx sectional view. The odd lenses 62o and the even lenses 62e are semi-circular convex lenses, which are regularly and alternately arranged on the transparent substrate 64 so that their condensing points (Fo, Fe) are on a straight line. To do. And
The lens array 60 is mounted on the optical waveguide array substrate 1 so that the respective condensing points coincide with the light incident positions on the end faces of the respective optical waveguides.
Bind to 0 (see FIG. 8). As a result, the odd-sided light beam 70o for scanning the odd-sided lens group is bent by the odd-sided lens 62o to enter the optical waveguide of the odd-numbered row, and the even-sided light beam 70e for scanning the even-sided lens group is
The light is bent by the even side lens 62e and enters the optical waveguides in the even rows. In FIG. 7A, laser scanning lines in odd fields are indicated by reference numeral 80o, and laser scanning lines in even fields are indicated by reference numeral 80e.

The light incident on the optical waveguide 44 propagates inside and contributes to the operation of the liquid crystal display as described in connection with the above embodiment. As described above, each convex lens 62
o and 62e serve to collect the scanned light beam and narrow it down to a predetermined incident point of the corresponding optical waveguide 44.
At that time, the position of the focal point does not change even during the scanning. Even if the position of the scanning light beam on the lens array changes, the lens array 60 allows the light beam to enter a fixed condensing point, which facilitates mechanical or temperature fluctuations and accuracy problems. It is possible to avoid it.

In this apparatus, first, the semiconductor laser optical system 5
The odd-numbered laser of 0 is turned on, and scanning is performed by the rotary polygon mirror 52. This odd side light beam 70o scans on the laser scanning line 80o of the odd side field in FIG. As a result, the odd-numbered light beam 70o is focused on the focusing point Fo and sequentially enters the corresponding odd-numbered optical waveguides. In the next scan, the even side laser is turned on. The even side light beam 70e scans the laser scanning line 80e of the even side field, and the converging point Fe
And the light is sequentially incident on the corresponding even numbered optical waveguides.
Interlaced scanning is optically realized by alternately performing the above scanning.

By the way, between the odd-side convex lenses 62o on the incident side end surface of the lens array 60, and the even-side convex lens 6
It is preferable to provide a light shielding layer 66 between 2e. Providing a light-shielding layer can prevent light from being instantaneously distributed to two adjacent optical waveguides when the light beam moves from one convex lens to the next convex lens, and prevents display crosstalk. You can For this purpose, the light-shielding layer preferably has a width larger than the diameter of the light beam.

In particular, in the present invention according to the above-described embodiment, when the rotating polygon mirror scans the light beam, it is difficult to precisely control the timing at which the light beam is incident on each optical waveguide due to uneven rotation or the like. There is. In such a case, it is preferable to provide a light detection element at the light beam scanning start position of the lens array and monitor the light beam. It is also possible to increase the number of both lens groups of the lens array by one from the number of optical waveguides, and provide a photodetector on the end surface of the optical waveguide array substrate corresponding to the extra lenses. As a result, a signal can be detected by the photodetector at the start of scanning the light beam, and if it is regarded as a frame start signal of an image, precise timing control such as writing of image information becomes possible.

Another embodiment of the present invention is shown in FIG. The photodetector array 90 is provided on the end face of the optical waveguide array substrate 10 on the emission side.
To provide. This photo-detecting element array 90 is provided for each optical waveguide 4
4 at the positions corresponding to the end faces of the light emitting side.
This is a structure in which two are arranged. The light amount of the scanning light beam varies due to displacement due to mechanical precision, temperature variation, and the like. Therefore, it is possible to install a light receiving element that monitors the light beam in the vicinity of the semiconductor laser and control the laser drive current so that the output is constant, but the light incident on the optical waveguide is caused by other mechanical factors. It may be fluctuating. With the above configuration, the light passing through each optical waveguide is incident on each corresponding photodetecting element 92, and the photocurrent due to the received light can be extracted to the outside. The current supplied to the semiconductor laser is controlled so that this photocurrent is substantially constant for all optical waveguide outputs. As a result, fluctuations due to various factors can be compensated, the amount of light incident on the optical waveguide can be controlled to a constant value, and addressing with light can be reliably performed.

Although the two reflecting mirrors are combined in each of the above-mentioned embodiments, they may be appropriately changed depending on the configuration of the optical system. Further, the lens array used in the present invention is not limited to the one manufactured as described above, and may be a lens formed by another method, for example, a Fresnel lens or a hologram.

[0040]

As described above, according to the present invention, the light beam is reflected by the rotary polygon mirror to be scanned and incident on the optical waveguide. Therefore, the number of parts is extremely small and the assembly is easy. In addition, it can be manufactured at low cost, and the stability of the operation is high because the adverse effect due to mechanical fluctuations is small.

Further, in the present invention, the light beam is scanned by being reflected by the rotary polygonal mirror, and is condensed by the lens array in which the odd-numbered lens group and the even-numbered lens group are arranged in two stages to collect the light on the odd-numbered side and the even-numbered side. By making it enter the optical waveguide,
Interlaced scanning can be easily realized by alternately performing scanning with two light beams.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an optical active matrix display according to the present invention.

FIG. 2 is a partially enlarged explanatory view thereof.

FIG. 3 is a basic configuration diagram showing an optical waveguide array substrate of an optical active matrix display according to the present invention.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a process diagram showing a method for manufacturing an optical waveguide array substrate of an optical active matrix display according to the present invention.

FIG. 6 is a schematic configuration diagram showing another embodiment of the optical active matrix display according to the present invention.

FIG. 7 is an enlarged explanatory diagram of a lens array.

FIG. 8 is an explanatory diagram showing a combined state of a lens array and an optical waveguide array substrate.

FIG. 9 is an explanatory diagram showing a mounting state of the photodetector array.

FIG. 10 is an enlarged cross-sectional view of a main part of a conventional optical active matrix.

FIG. 11 is a partially enlarged plan view of a conventional optical active matrix.

FIG. 12 is an explanatory diagram showing an optical scanning system of a conventional laser printer.

[Explanation of symbols]

1 Optical Switching Element 2 Picture Element Electrodes 5a, 5b, 5c Glass Substrate 7 Liquid Crystal Layer 10 Optical Waveguide Array Substrate 12 Transparent Substrate 14 Optical Waveguide 20 Laser Optical System 22 Rotating Polyhedral Mirror 24, 26 Reflector 28 Telecentric Optical System 30 Lens Array 32 Convex lens 34 Light-shielding layer X ₁ , ..., X _m Linear electrode Y ₁ , ..., Y _n Optical waveguide Z Optical fiber

Front page continuation (72) Inventor Yoshihiro Izumi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (11)

[Claims] 1. A plurality of optical waveguides arranged in one direction in a plane of a transparent substrate, linear electrodes for applying image signals arranged in a plurality so as to intersect the optical waveguides, and arranged in an array for image display. The array includes a picture element electrode and an array of optical switch elements that are located near the intersection of each optical waveguide and each linear electrode and connect the linear electrode and the pixel electrode. In an optical active matrix that changes the optical switch element from an off state to an on state by entering the switch element, the optical waveguides are formed so that their end faces appear on the transparent substrate and emit a light beam. Light source, a rotating polygonal mirror that changes the direction of the light beam, and a lens that changes the angle of the light beam reflected by the rotating polygonal mirror so that the light beam is incident on the end face of the optical waveguide regardless of the scanning direction. Optical active matrix display having an optical scanning device with a scanning system. 2. The optical active matrix according to claim 1, wherein the angle θ formed by the chief ray of the light beam incident on each optical waveguide of the transparent substrate with respect to the end face of the transparent substrate is substantially constant for each optical waveguide. display. 3. The angle θ according to claim 2, wherein the angle θ is approximately 90.
Optical active matrix display that is degree. 4. The lens array according to claim 1, wherein a lens array having lenses arranged at positions corresponding to individual optical waveguides is provided on an end face of the optical waveguide in the optical active matrix, and a light beam passing through the lens array is guided by a light beam. An optical active matrix display that focuses light near the end face of the waveguide. 5. The optical active matrix display according to claim 4, wherein an angle θ formed by a chief ray of a light beam incident on each lens of the lens array with respect to an end face of the lens array is substantially constant for each lens. 6. The light source according to claim 4 or 5, wherein the light source emits two light beams, and the lens array includes an odd-numbered lens group in which lenses are arranged at positions corresponding to the optical waveguides in the odd-numbered columns. The even-numbered lens groups in which lenses are arranged at positions corresponding to the optical waveguides in the even-numbered rows are provided in two stages, and the light beam for scanning the odd-numbered lens groups is provided in the odd-numbered optical waveguides and the even-numbered lens groups. An optical active matrix display in which the light beams for scanning light are alternately incident on the optical waveguides in even columns. 7. The optical active matrix display according to claim 1, wherein the lens system for allowing the light beam to enter the end face of the optical waveguide regardless of the scanning direction is composed of a telecentric optical system including a toric lens. 8. The optical active matrix display according to claim 1, wherein a light-shielding layer is provided on a portion of the end surface of the transparent substrate or the lens array on the incident side other than the light guide portion to the optical waveguide. 9. The optical active matrix display according to claim 8, wherein the width of the light shielding layer is larger than the diameter of the light beam incident thereon. 10. The light detecting element according to claim 1, wherein a light detecting element is provided at a position on the light beam scanning start side of the lens array or the transparent substrate, and writing of image information is controlled by using an output from the light detecting element as a trigger signal. Optical active matrix display. 11. The light detecting element array according to claim 1, wherein a light detecting element array is provided on the end face of each optical waveguide of the optical active matrix on the emission side, and the optical signal of each light detecting element is substantially constant. Active matrix display that controls the power supplied to the light source.