JPH06109999A - Analogue scanning converter of dmd - Google Patents

Abstract

PURPOSE: To provide an analog scanning converter by a deformable mirror device(DMD). CONSTITUTION: A scanning converter system is provided with a shift register 32 for receiving at least one system of serial input data from an input device 30, a converter 34 converting the data from serial to parallel connected to the shift register 32 and the DMD 36 connected to the converter 34 converting the data from the serial to parallel for forming an irradiation pattern almost the same as images received in the input device when a light source is reflected from the DMD.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to analog scan converters, and more particularly to constructing analog scan converters using deformable mirror devices (DMDs).

[0002]

BACKGROUND OF THE INVENTION Without intending to limit the scope of this invention, its background will be described in connection with systems utilizing IR sensors. Conventional devices that rely on linear IR sensors are being replaced with systems using multi-line sensors. These sensors have higher resolution and S /
The N-ratio aggregates are correspondingly higher, which reduces the problems associated with aliasing. Normally, these sensors have only the number of pixels required to scan the vertical dimension of the scene due to the complexity of manufacturing. The scene data sent out by shifting from these vertical sensors is naturally in the form of a vertical raster. However, the human eye is accustomed to seeing horizontal raster images. Therefore, such sensors generally require a scan converter to recreate the IR image in the visible region for human viewing. Typical, high dynamic range digital scan converters for accomplishing this task are expensive, bulky, heavy and consume a significant amount of power.

DMDs have several attractive features. The mirror element has a high reflectivity over a wide optical bandwidth. Therefore, light modulation from UV to IR can be performed.
Pixel response times are typically 10-20 μs and pixels can be operated in analog or digital modes. DMD by simple structural modification of the mirror
Can act as either an amplitude-dominant or phase-dominant modulator. DMDs can also be fabricated monolithically on low voltage, high density address circuits. The low power consumption of DMDs allows high frame rates (typically 5kHz and above) without the adverse effects of heating.

There are numerous DMD pixel structures, each designed for a particular application. They can be distinguished by deformation modes such as twist or cantilever, pixel shape, and hinge support structure.

[0005]

SUMMARY OF THE INVENTION The present invention discloses a scan converter system, a shift register receiving at least one stream of serial input data from an input device, and a serial to parallel connected to the shift register. And the DMD connected to the series to parallel converter,
The DMD produces an illumination pattern that is substantially the same as the image received at the input device when the light source is reflected from the DMD. The DMD images to a solid state detector, the detector is a CCD, the detector processes the image from the DMD and outputs the image from the detector in a different order than when the image was input to the detector. It is preferable to be able to do so. Alternatively, the DMD can be imaged on the back side of the scanning mirror and the image from the back side of the mirror can be optically projected to produce an image that is nearly identical to the image received at the input device. The DMD is preferably a torsion beam DMD. Examples of input devices are IR sensors or computers. The shift register, serial to parallel converter and DMD are preferably in a monolithic integrated circuit.

The invention is also a scan converter system in which at least one shift register receives at least one stream of serial input data from an input device and at least one serial to parallel converter coupled to the shift register. And at least one comparator whose input is connected to the output of the converter from series to parallel and whose other input is connected to the lamp voltage, and at least one DMD which is connected to the comparator, from the DMD to the light source. It provides a DMD that, when reflected, produces an illumination pattern that is substantially the same as the image received at the input device.
The comparator is a ramp comparator, shift register, serial to parallel converter, comparator and DM
Preferably D is in a monolithic integrated circuit.

The present invention also discloses a method of forming a scan converter system, generally receiving at least one stream of serial input data from an input device, converting the stream of serial data to parallel data, and DMD the parallel data. To produce an illumination pattern that is substantially the same as the image received at the input device when the light source is reflected from the DMD.

Referring now to the drawings, in which like reference numerals and characters refer to like parts throughout the drawings throughout, unless otherwise specified.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENT In a conventional IR system (FIG. 1), the input image 10 is focused by suitable optics 24 into the plane of an IR detector 12 configured as a row of discrete pixels. Of course, only one row of the image 10 can be detected at a predetermined time. Thus, one element of the imager is a mirror 14 that is pivotally mounted about its central axis, and by appropriately rotating the mirror 14, any desired row of the image 10 is directed to the detector 12. It can be focused.

The signals from each individual sensor element in detector 12 are connected to separate light emitting elements (typically LEDs) on linear array 16. This array 16
Visible light emitted by the mirror 14 is reflected by the backside 18 of the scanning mirror 14, and an observer 20 viewing the backside 18 of the mirror through a suitable optical system 22 views the scene 10 with the mirror 14 over the IR detector 12. When scanning, watch the input IR scene 10 play. Each individual connection path typically includes an amplifier which adjusts offset and linearity to compensate for pixel-to-pixel sensitivity and emission variations in both the detector and the emissive element. You can do it.

High-end IR sensors are usually composed of a plurality of rows of pixel elements rather than one row. By adding much more pixel elements to each detector, the number of output connections becomes very large. Such interconnects are often the cause of yield loss during manufacturing and field failures. Therefore, these high-end sensors often give priority to the serial shift register output for each column of pixels and discard the parallel pixel output. Connecting such a series output to an array of LEDs requires a complex arrangement, such as a monolithic LED board, which can either be a series-to-parallel converter or a separate series-to-parallel converter chip. It requires a complex hybrid substrate with a large number of single row LED arrays packaged on top of it. These types of cost-effective LED arrays are beyond the current state of the art, thus necessitating different types of displays. A canonical solution is shown in FIG. 2, which was to digitize multiple parallel or serial outputs 72 of a multi-line IR sensor 74 and store them in a digital video memory 70. Thereafter, the video memory 70 is read in series to drive the CRT display 76, or in parallel to drive a hybrid array of linear LED elements 78.

In the embodiment described below, the twist D
You can use MD. As shown in FIGS. 3 and 4, a twisted DMD pixel generally has a thick reflective beam 50 suspended above an air gap / spacer 52 and a sturdy support with two thin tensioned twist hinges 56 under tension. Alternatively, it is configured to be connected to the support layer 54. Address electrode 5 under beam 50
When 8 is biased, the twist hinge 56 twists and the beam 50
It rotates about the axis of one hinge 56 and rides on the landing electrode 60 below it. This structure is formed entirely on a substrate 62 of a material such as silicon. FIG. 4 shows some examples of hinges that can be used in twisted DMDs.

First to the display problem of high-end IR devices
The solution according to the preferred embodiment of the invention is shown in FIG.
The DMD chip 28 has an IR sensor device 3 having a chip structure.
It can be made to be almost the opposite of the structure of 0. Multiple analog serial shift registers 32 may be made on chip 28 or, if desired, may be external to the DMD chip. Its number and length should match the number and length of the output shift registers in the IR sensor device 30. Each shift register 32 preferably feeds through a series to parallel converter 34 to as many DMD pixels 36 as there are feeds from the corresponding shift register in IR device 30. Each DMD pixel 36 (possibly apart from the overall scale factor)
It can be an array similar to the array of pixels of R device 30. Thus, the visible (or other wavelength) light source reflected from the DMD produces almost the same illumination pattern as was incident on the sensor 30 in the IR spectrum.

In the second preferred embodiment, the reconstructed image is projected onto the backside 18 of the scanning mirror 14 shown in FIG. 1 and is visible in reflection from it. The operation of a conventional IR device can be reproduced without the expense of either a digital scan converter or a complex LED assembly.

Intensity can be encoded in the reflected image in several ways. One method is analog modulation. If the outputs of the DMD's analog shift register / serial to parallel converters 32, 34 are directly connected to the address electrodes below the pixel 36, each pixel 3
The deflection of 6 is proportional to the analog signal and therefore to the intensity of the input IR light. Using this degree of tilt of the DMD,
Analog light modulation is usually performed by using a dark field optical system.

In a dark field device, the DMD can be aligned so that the light reflected from the fully tilted DMD pixel is completely within the aperture of the display optics. The optical system is designed with a limited aperture so that the light reflected from the non-deflected pixels is completely outside this aperture. Of course, at an intermediate position, the amount of light reflected by this optical aperture is also an intermediate amount, thus creating an intermediate level of brightness in the plane of the projected image.

Another method of encoding intensity is pulse width modulation. The accuracy with which an image is reproduced based on analog modulation is related to the linearity and uniformity of the tilt angle of the DMD pixels and the proper apodization of the projection optics. Using pulse width modulation with the dark field optics described above eliminates both of these problems.

In the third preferred embodiment shown in FIG. 6, instead of driving the DMD pixel 36 directly from the output of the shift register / serial to parallel converters 32, 34, a slope comparator amplifier 38 (or the same). Any functional comparator type circuit) can be placed between the output of each shift register / serial to parallel converter 32, 34 and the corresponding address electrode of the DMD 36.

At the end of each series-to-parallel conversion, three things happen, as shown in FIG. The analog output of the shift register / serial to parallel converters 32, 34 (FIG. 6) is applied to one input 40 of the comparator at each DMD pixel 36 to provide the pixel at each pixel 36 location. The drive amplifier 42 is switched on to drive each pixel 36 to a fully tilted position, and the voltage common to the other input 44 of all comparators is detected from the lowest shift register signal level that can be detected. Start the ramp to the highest possible shift register signal level.

The rate of this ramp causes the ramp to reach its maximum voltage when the scanline time is complete. The output of the comparator 38 is connected to the input of the pixel drive amplifier 42 so that when each comparator 38 toggles, the output of the associated pixel drive amplifier 42 drops to zero and the associated DMD pixel 36 tilts. Try to return to the state where it is not. Thus, the amount of time a given pixel spends tilting during one scan line time (and thus the amount of light that this pixel provides to the display image during this scan line time) is calculated from the shift register / series. It is directly proportional to the voltage delivered to this pixel 36 by the converters 32, 34 in parallel.

If it is desired to have a separate display device (ie a display device which does not rely on the scanning performed by the back side of the input scanning mirror), either modulation scheme is used to mimic the operation of a digital scan converter. You can As an example of the function of this scan converter, the DMD can be imaged on the top row of an area array CCD (or other solid state) detector. At the end of each scanline time, CC
The charge generated in D can be shifted down one row in a manner similar to systole of the heart. The entire input image is CC
This sequence is advanced through the video frame time until it is stored in D. When that happens, the CCD can be read directly into the video of the CRT or other display device. The DMD can be imaged on the CCD in various ways. Multiple DMDs and CCDs can be combined and their outputs electronically manipulated to accomplish complex optical processing tasks.

Conversely, a linear DMD modulator can be used to generate a display from an image stored in, for example, a CCD or digital frame memory. The serial analog data stream may be taken directly from the CCD or taken from the frame memory via a digital-to-analog converter, but with IR detection initially. It is input to the analog shift register described as being supplied from the device. After this, normal IR
The scanning mirror is driven in the same way as the scanning mirror of the device is driven, and the image projected line by line from the DMD is viewed by reflection from the mirror surface.

If digital data is readily available, or if digital operation is considered preferable,
It is easy to use the DMD in digital mode. This digital mode requires the production of a unique DMD similar in structure to that described above. N
For a digital data stream with bit resolution, make N input shift registers in a linear DMD. Each shift register represents a digital bit of different resolution, most significant bit to least significant bit. Each shift register directly addresses its own row of DMD elements. The elements in each row are activated at the beginning of each scan line time. The most significant bitline is turned off in the middle of the scanline time, the next most significant at 1/4 of the scanline time, the third at 1/8 and so on. Thus, each pixel in each row of the image is illuminated by N pixels, each pixel illuminating for a period proportional to its weight in the binary sum. Thus, the total N
The binary light amplitude of the bit is obtained.

This binary irradiation weighting can be more easily realized by spatial weighting rather than temporal weighting. As previously mentioned, an N-bit binary data stream drives N input shift registers. However, in this scheme, each pixel along the shift register is spatially weighted. For example, in a device with 7-bit resolution, the most significant bit shift register drives 64 pixels at each DMD location. The next most significant bit drives 32 pixels. Next, say 16 pieces. This method does not require temporal resolution of less than scan line time because it weights the given percentage of irradiation by the percentage of available reflective area rather than the percentage of available time. These two methods of binary illumination weighting (time and space) may be combined.
As a result, the resolution of the pixel is further increased due to the increased dynamic range of the combined method.

The DMD can be used to be a display in many different embodiments. The DMD can be configured with the proper optics to act as a scan converter with reduced size, weight, cost and power budgets.
Further, the resulting DMD device, regardless of its source, can be displayed for viewing any stored digital image or analog data stream.

Above, some preferred embodiments have been described in detail. It should be understood that the scope of the present invention includes embodiments different from the ones described so far, which are also included in the scope of the claims. For example, the input device is IR
Although mentioned as a sensor, the input may come from many different sources such as a television signal or a computer. Although dark field optics have been described in connection with the use of this device, Schlieren optics or other suitable optics can be used. Similarly, the DMD may be used to display the image directly, or it may be sent to another detector for manipulation prior to display. In interpreting the scope of this invention, it is to be understood that the words used are not intended to be exhaustive in all cases.

Although the present invention has been described with reference to embodiments, this description should not be construed as limiting the invention.
From the above description, those skilled in the art can easily think of various modifications of the embodiment and other embodiments of the present invention. Therefore, it is to be understood that the appended claims are intended to cover such modifications or embodiments.

With respect to the above description, the following items will be further disclosed. (1) At least one of serial input data from the input device
A shift register for receiving two streams, a serial-to-parallel converter connected to the shift register, and a DMD connected to the serial-to-parallel converter, when a light source is reflected from the DMD. , A DMD in which an illumination pattern is created that is substantially identical to the image received by the input device.

(2) In the apparatus described in item (1),
A device in which a detector processes an image from a DMD so that the image is output from the detector in a different order than when the image was input to the detector.

(3) at least one shift register for receiving at least one stream of serial input data from an input device, at least one series-to-parallel converter connected to the shift register, and at least one comparator. An input of the comparator is connected to an output of the converter from the series to parallel, and another input is a comparator connected to a ramp voltage and at least one DMD connected to the comparator, A DM that produces an illumination pattern that is substantially the same as the image received by the input device when the light source is reflected.
A scan converter device including D.

(4) In the apparatus described in item (3),
A device wherein the comparator is a ramp comparator.

(5) The device as described in the item (1) or (3), in which the DMD forms an image on a solid-state detector.

(6) In the device described in the item (5),
A device whose detector is a CCD.

(7) In the device described in item (5),
A device in which a detector processes an image from a DMD so that the image is output from the detector in a different order than when the image was input to the detector.

(8) In the device described in (1) or (3), the DMD is a torsion beam DM.
A device that is D.

(9) The device described in the item (3), in which the DMD forms an image on the back side of the scanning mirror.

(10) The device described in the item (9), wherein the image from the back side of the mirror is optically projected to produce an image substantially the same as the image received by the input device.

(11) The apparatus according to item (1) or (3), wherein the input device is an IR sensor.

(12) In the device described in (1) or (3), the input device is a computer.

(13) The device according to item (1) or (3), wherein the shift register, the serial-to-parallel converter, the comparator and the DMD are in a monolithic integrated circuit.

(14) Receiving at least one stream of serial input data from an input device, converting the stream of serial data to parallel data, and sending the parallel data to a DMD in a method of forming a scan converter device. According to which, when the light source is reflected from the DMD, an illumination pattern is created that is approximately the same as the image received at the input device.

(15) The present invention discloses a scan converter system, wherein a shift register 32 receives at least one stream of serial input data from an input device 30, and a serial to parallel converter connected to the shift register 32. 34, and a DMD 36 connected to a series-to-parallel converter 34 that produces an illumination pattern that is substantially the same as the image received at the input device when the light source is reflected from the DMD.

(C) Copyright, * M * Texas Instruments Incorporated, 1991. A portion of the disclosure of this patent document contains material which is subject to copyright and masking protection. The owner of the copyright and mask work does not object to the facsimile reproduction of the patent document or the patent disclosure by anyone, as long as it appears in the Patent and Trademark Office patent file or record, but otherwise. , Reserve all copyrights and masking rights in any form.

[Brief description of drawings]

FIG. 1 is a diagram of a conventional IR image forming apparatus.

FIG. 2 is a block diagram of an electronic portion of a high-class IR image forming device.

FIG. 3 is a diagram of a twisted DMD.

FIG. 4 is a plan view showing an example of hinges of various twisted DMDs.

FIG. 5 is a diagram showing a first preferred embodiment of the present invention.

FIG. 6 is a diagram showing a third preferred embodiment of the present invention using pulse width modulation.

7 is a block diagram of a portion of the apparatus shown in FIG.

[Explanation of symbols]

 28 DMD Chip 30 IR Sensor Device 32 Shift Register 34 Serial to Parallel Converter 36 DMD

Claims (1)

[Claims] 1. A shift register for receiving at least one stream of serial input data from an input device, a serial-to-parallel converter connected to the shift register, and a serial-to-parallel converter. A DMD, which is a DMD, wherein a DMD produces an illumination pattern substantially the same as the image received by the input device when a light source is reflected from the DMD.