CN1882865A - High-density spatial light modulator - Google Patents

Abstract

In one embodiment, a high-density spatial light modulator (300) includes a substrate (402) having a reflective surface (404) and a reflective ribbon (304) over the reflective surface. The ribbon (304) may have one or more openings, such as rectangular slots (308). The openings allow light to pass through the ribbon and impinge on the reflective surface. Deflecting the ribbon (304) towards the substrate (402) thus allows for dynamically-controllable diffraction of incident light. The spatial light modulator pixel requires less space than a conventional light modulator, thus allowing for relatively large pixel count within a manufacturable device size. Other embodiments are also disclosed.

Description

High-density spatial light modulator

The cross reference of related application

No. the 60/506624th, the U.S. Provisional Application that the present invention claimed inventor Jahja I.Trisnadi and Clinton B.Carlisle submitted on September 26th, 2003, name is called the right of " spatial light modulator (Spatial light modulator) ".The instructions of above-mentioned U.S. Provisional Application all is incorporated herein by reference.

Technical field

The present invention relates generally to photomodulator, especially but not exclusively relate to spatial light modulator based on MEMS (micro electro mechanical system) (micro electromechnical system MEMS).

Background technology

Generally speaking, it is known utilizing the spatial light modulator of MEMS (micro electro mechanical system) (MEMS) technology manufacturing.The example of this photomodulator comprises the Grating Light Valve that can obtain from the Silicon Light Machines Corporation of California Sani Wei Er ^TM(GLV ^TM) photomodulator.Hereinafter will with GLV ^TMThe device that the photomodulator type is identical is called " belt photomodulator ".The belt photomodulator has been described in the following description book, it is the part of this provisional application, and can in following patent, find: No. the 5311360th, people's such as Bloom United States Patent (USP), name is called " method and apparatus (Method andApparatus for Modulating a Light Beam) that is used for modulated beam of light "; No. the 5841579th, people's such as Bloom United States Patent (USP), name is called " flat diffraction grating light valve (Flat Diffraction GratingLight Valve) "; No. the 5661592nd, people's such as Bornstein United States Patent (USP), name is called " method and apparatus (Method of Making and anApparatus for a Flat Diffraction Grating Light Valve) that is used to make flat diffraction grating light valve "; No. the 6215579th, people's such as Bloom United States Patent (USP), name are called " method and apparatus (Method and Apparatus for Modulating an IncidentBeam for Forming a Two Dimensional Image) that is used to modulate the incident beam that forms two dimensional image ".Aforesaid four pieces of american documentation literatures are incorporated herein by reference in this article.The belt photomodulator can obtain utilizing in various application, comprises optic network, video and printing.

Fig. 1 and 2 has represented the synoptic diagram of conventional belt photomodulator structure.In Fig. 1, each band 102 with reflection horizon 103 can have reflection horizon 106 towards substrate 104 electrostatic deflection on the substrate 104, thereby forms the diffraction grating with adjustable diffracted intensity.In Fig. 2, but active deflection band 202 and static on-deflectable band 204 are staggered, thereby have also formed the addressable diffraction grating with adjustable diffracted intensity.In Fig. 2, substrate 208 need not to have reflective surface layer.Band 102 among Fig. 1 and gap 108 (band-gap) to 110 or Fig. 2 in active band 202 and static band 204 (band-band) constituted the diffraction cycle to 206.One or more cycles can be carried out addressing as " pixel ".Can address pixel with by the diffraction modulating the incident light.Therefore, pixel energy is enough in demonstration or prints such as image as unit.

Although conventional spatial light modulator can be used for multiple high-resolution applications satisfactorily, also there is the emerging application that may need higher pixel resolution.The example of these emerging application comprises the high resolving power printing of ultrahigh resolution display, maskless lithography, printed circuit board (PCB) and flat-panel monitor and other application in a large number.Also have many existing application that can utilize the high resolution space photomodulator to be significantly improved, for example laser printer.

Summary of the invention

In one embodiment, a kind of high-density spatial light modulator comprises substrate with reflecting surface and the reflection band that is positioned on the reflecting surface.This band can have one or more openings, for example rectangular slot.Opening can make light pass through band, and incides on the reflecting surface.Therefore, make band can make dynamically diffraction controllably of incident light towards substrate deflection.Spatial light modulator pixel needs less space than conventional photomodulator, thereby can obtain bigger pixel count.

Comprise present disclosure whole of respective drawings and claim by reading, these and other feature of the present invention is conspicuous for those of ordinary skills.

Description of drawings

Fig. 1 has schematically illustrated conventional belt photomodulator structure.

Fig. 2 has schematically illustrated another kind of conventional belt photomodulator structure.

Fig. 3 has schematically illustrated the top view according to the high density belt photomodulator of the embodiment of the invention.

Fig. 4 has schematically illustrated the central cross section figure of the belt photomodulator of Fig. 3.

In different accompanying drawings, use same reference numerals to represent same or analogous parts.Unless each accompanying drawing is dated especially, otherwise needn't proportionally draw.

Embodiment

In this manual, provide many specific details, the example of device, parts and method for example is can understand embodiments of the invention up hill and dale.Yet, persons of ordinary skill in the art will recognize that the present invention can also can realize under the situation of neither one or a plurality of above-mentioned specific detail.In other cases, do not represent or describe known details, to avoid making feature of the present invention smudgy.

The present invention relates to a kind of diffraction spatial light modulator.Although utilize linear belt photomodulator to describe embodiments of the invention as an example, should be appreciated that to the invention is not restricted to this, and also can be used for the spatial light modulator of other type.

Fig. 3 and 4 has represented the synoptic diagram according to the high density of the embodiment of the invention or high pixel count, linearity, diffraction space belt photomodulator 300.Fig. 3 has represented the top view of the embodiment of photomodulator 300, and Fig. 4 has represented by cut the cross-sectional view of this embodiment of viewed photomodulator 300 along line illumination 302 shown in Figure 3.Photomodulator 300 can have several to thousands of, or more reflects band, but has only represented 4 bands 304 in order to clearly demonstrate.The end of each band 304 can utilize binding post 306 or other device to fix.Substrate below band 304 and the band preferably has reflective upper surface, and is separated by the clearance.In the example of Fig. 4, the reflection horizon 404 that the upper surface of substrate 402 covers on being shown and having.Each band 304 preferably also has this reflection horizon (as illustrated in fig. 1 and 2) on the surface thereon.Each band has one or more openings of rectangular slot 308 forms.Slit 308 can make that part illumination is bright to be labeled as the shadow region of " line illumination ", thereby shines the reflection horizon 404 of the substrate 402 under the band 304.In a preferred embodiment, this spatial light modulator 300 is arranged such that: a) the area reflectivity product that causes owing to the reflection horizon on the band, and b) since band in and band between the area reflectivity product approximately equal that opening caused.Utilize with the conventional belt photomodulator process of manufacturing in the similar MEMS treatment technology that adopts, can produce photomodulator 300.

The middle body of reflection band 304 (in being between the fixed part) can make it towards substrate deflection owing to for example electrostatic force.Make band 304 deflections change distance between the reflection horizon 404 of the upper surface of band 304 and substrate 402, thereby changed the path length difference that shines the light on them.So just make incident light obtain modulation by diffraction.

In photomodulator 300, the diffraction cycle " Λ " comprises a strip face and an opening.Addressable pixel " P " has " N " individual cycle/pixel (being P=N Λ).In the example of Fig. 3 and 4, each pixel has three cycles.Notice that the gap 310 between the band has identical effect with slit 308.Therefore, strip width " W " is provided by equation W=P-(Λ/2).Photomodulator 300 can be according to zero level or first class mode work.Under zero mode, collect the zero level composition of light, and by this optical diffraction being become one-level and more senior the acquisition modulate.Under first class mode, collect the modulated one-level composition of light.Yet, because the cycle of photomodulator 300 may only be several wavelength, so angle of diffraction can be very big.Therefore, preferably handle photomodulator 300 with zero mode.

Distance " H " is the distance between the reflection horizon of the reflective upper surface of band and substrate.If H=(odd-integral number) (λ/4), wherein " λ " is the incident light wavelength, and photomodulator 300 is generally OFF so.In other words, deflection state is not a diffraction, thus discarded light, corresponding to the dark pixel under the zero mode.If H=(even-integral number) (λ/4), this photomodulator 300 is generally ON so.That is to say that deflection state is not reflection, corresponding to the bright pixel under the zero mode.Can close (snap down) because band surpasses under the situation of H/3 in deflection, then Zui Xiao even-integral number and odd-integral number multiplier preferably are respectively 4 and 5.Can add height nargin δ to distance H, to allow even calibration.In other words, the photomodulator 300 that is generally OFF can be configured to H=M (λ/4)+δ, wherein M is not less than 5 odd-integral number (being M=5 or 7 or 9 or 11 etc.), and the photomodulator 300 that is generally ON can be configured to H=M (λ/4)+δ, and wherein M is not less than 4 even-integral number (being M=4 or 6 or 8 or 10 etc.).

As particular instance, Λ=1 micron (μ m), and N=3 cycle/pixel, thus obtain P=3 μ m (i.e. 1 μ m * 3).Gap between slit width and the band equals (Λ/2) or 0.5 μ m (i.e. 1 μ m/2) respectively.Strip width W is 2.5 μ m (i.e. 3 μ m-(1 μ m/2)).For the light source of wavelength X=0.5 μ m, the photomodulator that is generally OFF can have the distance H (odd-integral number=7) of the distance H of 0.625 μ m (odd-integral number=5) or 0.875 μ m.For 10,000 (10000) individual pixels, circuit small pieces is only long for about 30mm (10000 * 3 μ m).

For the ribbon structure of～λ, can adopt omnidirectional's amount diffraction analysis to come the working condition of optimised devices, and solve with the interactive polarization of the light field of this structure and influence.Equally, the drive electronics of each pixel can be integrated on the same silicon chip as ribbon structure, thereby obtain very high pixel count and meticulous pixel separation.

A kind of big pixel count, diffraction, spatial light modulator are disclosed.This modulator can be configured to linear array, alternatively is configured to two-dimensional array.Although specific embodiment is provided, be to be understood that these embodiment are used to illustrate, and unrestricted.Those of ordinary skills are after having read present disclosure, and many additional embodiments all will be very well-known.

Claims (21)

1. MEMS spatial light modulator comprises:

Substrate with reflecting surface;

Band on the reflecting surface, this band has reflecting surface, and middle body also have one or more openings be used to make light by and incide reflecting surface;

Wherein can make this band towards substrate deflection, so that according to controlled manner diffraction incident light.

2. photomodulator according to claim 1 wherein can utilize electrostatic force to make the bar belt deflector.

3. photomodulator according to claim 1, wherein this photomodulator is configured to controllably make the quarter-wave of the about light of bar belt deflector.

4. photomodulator according to claim 1 also comprises second band that can make it towards reflecting surface deflection.

5. photomodulator according to claim 4, wherein the gap between two bands has identical distance with the width of band split shed.

6. photomodulator according to claim 1, wherein each opening comprises slit.

7. photomodulator according to claim 6, wherein this slit is rectangle basically.

8. photomodulator according to claim 1, wherein the width of each opening equals two distances between the opening.

9. photomodulator according to claim 1 is wherein controlled to represent single pixel this band.

10. photomodulator according to claim 1, wherein the not deflected height of band is approximately equal to the quarter-wave of light and the product of an integer.

11. photomodulator according to claim 10, wherein this integer is at least and avoids the close minimum number of situation of band when making the bar belt deflector.

12. photomodulator according to claim 11, wherein this minimum number is 4.

13. photomodulator according to claim 10, wherein this integer is an odd number, and at this band diffraction light during deflection not.

14. photomodulator according to claim 10, wherein this integer is an even number, and at this band specular light during deflection not.

15. a high-density spatial light modulator comprises:

Substrate;

But be configured in the deflection band device array on the substrate;

One or more openings in each band device;

Opening between the adjacent ribbons device;

Reflection horizon on each band device;

At least be configured in the reflection horizon on the substrate under the described opening; And

Wherein this spatial light modulator is arranged such that: a) the area reflectivity product and the b in the reflection horizon on the band) in the band and the area reflectivity product approximately equal of the opening between the band.

16. spatial light modulator according to claim 15, wherein this array comprises linear array.

17. spatial light modulator according to claim 15, wherein this array comprises two-dimensional array.

18. spatial light modulator according to claim 16, wherein the cycle of the band device in this linear array is per 3 millimeters or littler band device.

19. spatial light modulator according to claim 16, wherein this array comprises 10000 band devices in single circuit small pieces, and wherein each band device is corresponding to controllable pixel.

20. the method for a spatial modulation light, this method comprises:

The light of certain wavelength is incided on the band device array on the substrate;

Controllably make the deflection of band device,

Wherein this substrate comprises reflecting surface, and

Wherein each band device comprises reflecting surface, and comprises also that at middle body one or more openings are to be used to that light is passed through.

21. method according to claim 20, wherein single at least band device is corresponding to independent controllable pixel.