CN1381753A

CN1381753A - Method for modulating protection light

Info

Publication number: CN1381753A
Application number: CN 01107963
Authority: CN
Inventors: 蒋正旺
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-04-17
Filing date: 2001-04-17
Publication date: 2002-11-27

Abstract

A method for modulating the light beams of projection display is disclosed. A light beam is emitted from an optically denser medium to an optically thinner medium (such as air) and its incident angle is greater than or equal to the full-reflecting critical angle. The full reflection takes place at the interface between two media. When liquid or liquid drop is in contact with the reflecting interface, the reflection does not occur. The liquid or liquid drop can be iosolated from the said interface by lattice net and can be driven by electric field to control the reflection of light beam.

Description

A kind of new Projection Display light modulating method

Present technique belongs to projection display technique.

In the shadow casting technique, except that CRT projector used the projection cathode-ray tube Display projector, LCD shadow casting technique, DLP shadow casting technique all needed projecting beam is modulated now.

Liquid crystal technology adopts the liquid crystal optical switch in the liquid crystal board to carry out light modulation, controls average logical light quantity with the length between the logical light time and realizes the gradation of image level.

The DLP technology adopts the micro mirror photoswitch in the dmd panel to carry out light modulation, also controls average logical light quantity with the length between the logical light time and realizes that gray scale shows.

The present technique purpose provides a kind of new Projection Display light modulating method.

Present technique be with light by optically denser medium directive optically thinner medium (as air), and make incident angle more than or equal to the light total reflection critical angle.Total reflection will take place at two medium interface places in light.Light reflected back optically denser medium is gone out by projection again.

When be in light thinning medium this on one side, and the refractive index liquid equal with light substantia compacta or drop be when contacting with the interface, light just can penetrate in liquid or the drop.If add light absorbent within it or in its back light absorbent is arranged, light will be absorbed, no longer reflection.

As seen above device can be as photoswitch.It is the core of this technology, and a lot of photoswitches combine, and adopts the average logical fader control gray-level that length is controlled each switch between the logical light time of control, just can carry out image and show.

For making these photoswitches, can be on the reflecting interface of light thinning medium in normal direction, by liquid repellent not infiltrating material produce a lot of cross bar rulings, as isolating aperture plate.To near liquid lamella graduation come apart from this interface, or drop will be kept apart.Liquid or drop in each grid are corresponding with a photoswitch.

For making controlling liquid or drop well, with normal direction towards the interfacial separation of light thinning medium with contact, can adopt:

1. by electric field force control.Can make electric charge on liquid or the drop band, when electric field force meets the demands, can order about they and interfacial separation, when electric field changes direction, order about them again and contact with the interface.

2. by surface tension of liquid and electric field force control.

When aperture plate is enough close, lean on the not mesh lines repulsion of the formation of infiltrating material of liquid repellent, and the surface tension of liquid self, liquid will not see through aperture plate, not contact with interfacial separation, and when driving with electric field force, liquid sees through aperture plate and contacts with the interface.

For making each photoswitch can both be met the electric field of requirement, can make each photoswitch all corresponding with LCD panel or dmd panel on similar frame storage storage.

Embodiment: as Fig. 1, be a new-type projected light modulation panel of making by above know-why, 1. be on the substrate with similar thin-film transistor circuit of liquid crystal technology and electrode.2. be separation layer 3. be refractive index equate with optically denser medium photoswitch liquid 4. gridline 5. reflecting interface 6. optically denser medium 7. with 8. anti-reflection film of the transparency electrode of refractive indexes such as optically denser medium

This light modulation panel adopt 1. 8., be and similar electrode structure of active LCD panel and active matrix frame memory circuit.

Fig. 2 is an active matrix frame memory circuit composition diagram. it constitutes a matrix by the directions X scanning utmost point and Y direction signal electrode. as shown in Figure 3, X, Y electrode intersection point place constitute a display pixel cells by a photoswitch and a thin film transistor (TFT) (TFT) switch.Apply strobe pulse voltage on the line scanning electrode successively, be used for encouraging each TFT pipe conducting of this row.The row signal drive circuit is added to signal pulse on the signal electrode with sweep gate impulsive synchronization ground.Signal electrode is attached in the TFT drain electrode, and signal pulse is charged to photoswitch electric capacity through the TFT of conducting.To next line period, scanning impulse moves to the next line scan electrode, and originally Hang all TFT end, make electric charge (voltage) on the electric capacity protect selected next time till.

In per frame period, information refreshes once at regular intervals on each unit of storer, to control the make-and-break time width of each photoswitch, controls the mean flow rate of each projected pixel, and then makes entire image obtain the gray-level that needs.

Claims

A kind of new-type Projection Display light modulating method is characterized in that:

By optically denser medium directive optically thinner medium (as air), and make incident angle light more than or equal to the light total reflection critical angle.Total reflection will take place at two medium interface places in light.Light reflected back optically denser medium is gone out by projection again.

When be in light thinning medium this on one side, and the liquid that equates of refractive index and optically denser medium or drop be when contacting with the interface, light just can penetrate in liquid or the drop, no longer reflects.