CN203250067U - Digital projection device based on non-telecentric optical path - Google Patents

Abstract

The utility model discloses a digital projection device based on a non-telecentric optical path. The digital projection device comprises a digital micromirror wafer, a projection lens, a light guide tube, a first reflector and a second reflector, wherein the digital micromirror wafer and the projection lens are oppositely arranged, and the light guide tube, the first reflector and the second reflector are set according to a certain incident angle. After being emitted from the light guide tube, light is reflected by the first reflector and the second reflector, thereafter is projected on the digital micromirror wafer; after being reflected by the digital micromirror wafer, the light is imaged on a projection screen; the first reflector is a plane reflector; and the second reflector is a hyperboloid reflector. According to the digital projection device based on the non-telecentric optical path of the utility model, the hyperboloid reflector is adopted as the second reflector, and therefore, optical efficiency, contrast ratio and uniformity can be improved, and the realization of high brightness and miniaturization of the projection device can be facilitated.

Description

Digital projection device based on non-telecentric beam path

Technical field

The utility model relates to a kind of digital projection device, relates in particular to a kind of digital projection device based on non-telecentric beam path.

Background technology

DLP is the abbreviation of " Digital Light Procession ", is digital light and processes, and that is to say that this technology is first the digital processing of signal of video signal process, and then light is projected.The principle of DLP is that light that light source is launched shines on digital micro-mirror wafer (DMD) chip after through one section optical processing, by the DMD reflection and through projection lens imaging on projection screen.

In modern DLP optical projection, the one chip projection display system is divided into the heart far away and two kinds of structures of the non-heart far away.In the core structure far away, the emergent pupil of illuminator (entrance pupil of projection objective) is positioned at DMD device surface infinite distance or enough on the position far away, the chief ray that shines on each DMD small reflector is parallel to each other.As shown in Figure 1, digital micro-mirror wafer 1 and projection lens 2 are oppositely arranged, light pipe 3 and the first catoptron 4, the second catoptron 6 are certain angle of inclination and arrange, light is incident upon on the digital micro-mirror wafer 1 after by the first catoptron 4 and the reflection of the second catoptron 6 from light pipe 3 outgoing, through projection lens 2 imaging on projection screen, adopt total reflection prism (TIR) to distinguish illumination path and signal light path as the second catoptron in the system after being reflected by digital micro-mirror wafer 1 again.

A major defect of telecentric light optical texture is to introduce complexity and the cost that the TIR prism has not only increased system, and the reflection on each surface of prism also can reduce the utilization factor of system's luminous energy.And the interval is little between illuminating bundle, bright attitude light beam, dark attitude light beam and the plane reflection light beam, and useless parasitic light easily enters projection objective and causes that system contrast descends.For improving contrast, usually need to sacrifice certain capacity usage ratio.Can cause the increase of projection objective bore when system adopts eccentric design in addition, cause the total system volume to increase.

In the non-core structure far away, the emergent pupil of illumination path is positioned near on the position on dmd chip surface, requires equally the position of projection objective entrance pupil and the emergent pupil of illuminator to be complementary.The design quality of the second catoptron 6 directly has influence on the projection indexs such as optics utilization factor, contrast and homogeneity of final complete machine.The second catoptron 6 general spheric reflection or elliptical areas of adopting reflect in the existing non-core structure far away, are that optical aberration is large, distortion is serious, the volume of its element own is larger and adopt this dual mode to have drawback.It is fan-shaped that larger distortion can cause above the final arrival dmd chip light spot shape to occur.In order to address this is that, the common way in the industry is that whole facula area is increased, but this can cause larger light energy losses again.

The utility model content

Technical problem to be solved in the utility model provides a kind of digital projection device based on non-telecentric beam path, can improve optics utilization factor, contrast and homogeneity, is conducive to projection arrangement and realizes high brightness, microminiaturization.

The utility model is to solve the problems of the technologies described above the technical scheme that adopts to provide a kind of digital projection device based on non-telecentric beam path, comprise the digital micro-mirror wafer, projection lens, light pipe, the first catoptron and the second catoptron, described digital micro-mirror wafer and projection lens are oppositely arranged, described light pipe and the first catoptron, the second catoptron is by certain incident angle setting, light is incident upon on the digital micro-mirror wafer after by the first catoptron and the second mirror reflects from light pipe incident, again by after the digital micro-mirror wafer reflection through projection lens imaging on projection screen, wherein, described the first catoptron is plane mirror, and described the second catoptron is hyperboloidal mirror.

The above-mentioned digital projection device based on non-telecentric beam path, wherein, the surface equation of described hyperboloidal mirror is:

$z=\frac{{\mathrm{<figure-callout\; id="2"\; label="cr"\; filenames="HDA00003056792500012.png"\; state="\{\{state\}\}">cr</figure-callout>}}^2}{1+\sqrt{1-(1+k)}{c}^2{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00003056792500012.png"\; state="\{\{state\}\}">r</figure-callout>}}^2};$

K=-e ²Perhaps $k=(1-e^2)*\frac{a^2}{b^2};$

K is the light cone coefficient of curved surface, and e is eccentricity, and c is the high-order term coefficient, and a, b are hyp half real axis, and r is radius-of-curvature.

The above-mentioned digital projection device based on non-telecentric beam path wherein, also is provided with relay lens behind the described light pipe.

The utility model contrast prior art has following beneficial effect: the digital projection device based on non-telecentric beam path that the utility model provides, be the second catoptron by adopting hyperboloidal mirror, thereby improve optics utilization factor, contrast and homogeneity, be conducive to projection arrangement and realize high brightness, microminiaturization.

Description of drawings

Fig. 1 is existing digital projection device structural representation based on telecentric beam path;

Fig. 2 is that the utility model is based on the digital projection device structural representation of non-telecentric beam path;

Fig. 3 is that the utility model is based on digital projection device mid-focal length and the numerical aperture Relations Among schematic diagram of non-telecentric beam path;

Fig. 4 is that the utility model is based on digital projection device structure mid-focal length and the focal length Relations Among schematic diagram of non-telecentric beam path.

Among the figure:

1 digital micro-mirror wafer, 2 projection lens, 3 light pipes

4 first catoptrons, 5 relay lenss, 6 second catoptrons

Embodiment

The utility model will be further described below in conjunction with drawings and Examples.

Fig. 2 is that the utility model is based on the digital projection device structural representation of non-telecentric beam path.

See also Fig. 2, the digital projection device based on non-telecentric beam path that the utility model provides comprises digital micro-mirror wafer 1, projection lens 2, light pipe 3, the first catoptron 4 and the second catoptron 6, described digital micro-mirror wafer 1 and projection lens 2 are oppositely arranged, described light pipe 3 and the first catoptron 4, the second catoptron 6 is by certain incident angle setting, such as at XYZ three dimensions, the second catoptron 6 is 0 ° of placement at the XY face, the second catoptron 6 is 6.979 ° of placements at the YZ face, XZ is by 5.596 ° of placements, so that light is incident upon on the digital micro-mirror wafer 1 after by the first catoptron 4 and the reflection of the second catoptron 6 from light pipe 3 outgoing, again by after digital micro-mirror wafer 1 reflection through projection lens 2 imaging on projection screen, wherein, described the first catoptron 4 is plane mirror, and described the second catoptron 6 is hyperboloidal mirror.Also can be provided with relay lens 5 behind the described light pipe 3.Described hyperboloidal mirror preferably adopts the one-shot forming of pressure injection mode, has that the process-cycle is short, cost is low, the yields advantages of higher.

Position as the plane in the perfect optical system logitudinal magnification is the function of object plane position, functional relation is Gauss formula and Newton's formula, when object plane is made the mobile dx of a trace or dl along optical axis, its as the plane just mobile one accordingly apart from dx ' or dl '.Magnification by

Try to achieve

Focal length ltanU=h=l ' the tanU ' of system

(x+f)tanU=(x′+f′)tanU′

X and x ' Relations Among

x=-f(y/y′)

x′=-f′(y′/y)

fytanU=f′y′tanU′

Relation between focal length and the numerical aperture, wherein U is the object space aperture angle, object distance represents with x, image distance x ', sign is determined take corresponding focus as initial point, if consistent with the light transmition direction to the direction of propagation of A ' to A or F ' by F, then for just, otherwise for negative.As shown in Figure 3, focal length and focal length Relations Among are as shown in Figure 4.When thereby the index that will reach according to whole illuminator after system's focal length, magnification and structure are determined is calculated, optimized and analyze by the respective optical design software.

Because of the circular cone coefficient k=-e ², perhaps

Wherein e is eccentricity, because the eccentricity of conic section and axial length relation:

Wherein c is that high-order term coefficient a is hyp half real axis, and k is curved surface light cone coefficient.

Therefore, the preferred aspheric fundamental equation of hyperboloidal mirror is:

Final design draws radius-of-curvature and curved surface light cone coefficient.

What the utility model provided adopts the design of hyperboloidal mirror based on the digital projection device of non-telecentric beam path, and relatively conventional sphere or the elliptical area of adopting of its aberration reduces greatly.Difference and angular magnification that the reason that common distortion produces mainly contains the stop position cause.Its distortion is:

$q^{\&prime;}=\frac{{{\mathrm{\&delta;y}}_z}^{\&prime;}}{y^{\&prime;}}\&times;100\%=\frac{\stackrel{\&OverBar;}{\mathrm{\&beta;}}-\mathrm{\&beta;}}{\mathrm{\&beta;}}\&times;100\%$

δ y wherein _z' be Gauss's image planes height, y ' is desirable image height,

Be the vertical axle enlargement ratio of the reality of maximum field of view; β is the desirable axle enlargement ratio that hangs down of optical system.Because distortion only has relation with object height y or field angle, change along with the change of y, when the distortion correction at maximum field of view place arrives zero,, improved and adopted other modes in the industry and form the illumination hot spot and have the fan-shaped problem that causes luminous energy that greater loss is arranged on shine DMD the time less than 5% at the maximum deformation quantity at 0.707 visual field place.And the utility model hyperboloidal mirror is found processing and dress error requirements lower by theoretical and practical set, relatively adopts sphere and other modes to realize more guaranteeing yield and stability when volume production in the industry.

Although the utility model discloses as above with preferred embodiment; so it is not to limit the utility model; any those skilled in the art; within not breaking away from spirit and scope of the present utility model; when doing a little modification and perfect, therefore protection domain of the present utility model is worked as with being as the criterion that claims were defined.

Claims (3)

1. digital projection device based on non-telecentric beam path, comprise digital micro-mirror wafer (1), projection lens (2), light pipe (3), the first catoptron (4) and the second catoptron (6), described digital micro-mirror wafer (1) and projection lens (2) are oppositely arranged, described light pipe (3) and the first catoptron (4), the second catoptron (6) is by certain incident angle setting, light is incident upon on the digital micro-mirror wafer (1) after by the reflection of the first catoptron (4) and the second catoptron (6) from light pipe (3) outgoing, again by after digital micro-mirror wafer (1) reflection through projection lens (2) imaging on projection screen, it is characterized in that, described the first catoptron (4) is plane mirror, and described the second catoptron (6) is hyperboloidal mirror.

2. the digital projection device based on non-telecentric beam path as claimed in claim 1 is characterized in that, the surface equation of described hyperboloidal mirror is:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-(1+k)}{c}^2{r}^2};$

K=-e ²Perhaps $k=(1-e^2)*\frac{a^2}{b^2};$

K is the light cone coefficient of curved surface, and e is eccentricity, and c is the high-order term coefficient, and a, b are hyp half real axis, and r is radius-of-curvature.

3. the digital projection device based on non-telecentric beam path as claimed in claim 1 or 2 is characterized in that, also is provided with relay lens (5) behind the described light pipe (3).

Images