Summary of the invention
The present invention makes in view of above-mentioned such problem, and its purpose is, provides a kind of and is using image modulation element to reduce the appropriate technology of image quality aggravation under as the situation of image forming source.
In order to realize purpose of the present invention, the invention is characterized in that in the both sides or a side of image-displaying member, the angle of visibility that the direction at the magnification field angle is provided for correction image light amplifies film.Amplifying film as this angle of visibility, can be the film upper-part of using for the view angle compensation of P ripple different with its refractive index of S ripple (promptly having a plurality of refractive indexes).
In addition, in the present invention, image-displaying member is reflective liquid crystal plate or mirror reflects type optical modulation element, and its reflecting surface is a uneven surface.
In addition, in the present invention, the light path from image-displaying member to described projecting lens, configuration is used for and will be become the scattering part of scattering by the light of the formed image of this image-displaying member.This scattering part also can be arranged near the image-displaying member.
At image-displaying member is under the situation of permeation type liquid crystal plate, any one or their combination in below can using as above-mentioned scattering part:
(1) has the emitting side dustproof glass of the fuzzy value bigger (haze) than light incident side dustproof glass;
(2) or the diffusion sheet pasted bonding with the emitting side dustproof glass;
(3) diffuser plate that between permeation type liquid crystal plate and emitting side polarization plates, disposes;
(4) has the emitting side polarization plates of the fuzzy value bigger than light incident side polarization plates;
(5) dichroic prism of synthetic red, blue, the green image that penetrates from a plurality of permeation type liquid crystal plates, with the plane of incidence or outgoing plane is bonding or the diffusion sheet of stickup.
In addition, be under the situation of reflective liquid crystal plate at image-displaying member, as above-mentioned scattering part, any one during use is following or their combination:
(1) is used to protect dustproof glass reflective liquid crystal plate, that have the fuzzy value bigger than the fuzzy value of general dustproof glass;
(2) with the diffusion sheet of dustproof glass surperficial bonding or stickup;
(3) with spectroscopical outgoing plane or the plane of incidence is bonding or the diffusion sheet pasted.
In addition, be to have under the situation of mirror reflects type modulator element of a plurality of catoptrons at image-displaying member, as above-mentioned scattering part, use dustproof glass with fuzzy value bigger than the fuzzy value of general dustproof glass.
According to the formation of the invention described above, using under the situation of image modulation element, can reduce the image quality aggravation that causes by for example spot fault etc.
Embodiment
Embodiments of the present invention are described with reference to the accompanying drawings.
Fig. 1 is a part of cross-sectional perspective view of image display device of the present invention.In Fig. 1, image forming source 1 is made of projection type Braun tube or reflection-type or permeation type liquid crystal plate, lamp optical systems such as image modulation element, lamp such as mirror reflects type optical modulation element etc. with a plurality of small catoptrons, shows compact image.Projecting lens 2 to back projection type screen 3, but because generally projector distance is long, in order to reduce the depth of image display device, is provided with catoptron 4 with described image projection in this light path.Framework 5 is is fixedly received and kept assigned position with these image forming sources 1, projecting lens 2, back projection type screen 3, catoptron 4.
Fig. 2 is the synoptic diagram of structure of the image forming source 1 of expression use permeation type liquid crystal plate of the present invention.Ejaculation light from as the lamp 6 of light source incides the multi lens array that is made of light incident side multi lens array 7a and emitting side multi lens array 7b, and homogenized.Then, make its polarization direction unanimity by optical splitter 8, this light beam converges by collector lens 9.Because first catoptron 10 is used for image forming source 1 integral miniaturization, so will change its working direction from the beam reflection of collector lens 9.The light that is reflected by first catoptron 10 incides on first collimation lens 11, and this first collimation lens 11 is used for the ejaculation light of lamp 6 is gone up and the focus coupling at panel (back description).First dichronic mirror 12 sees through from the red light in the light of first collimation lens 11 reflect blue light and green light.Second dichronic mirror 13 is through blue light that is reflected by this first dichronic mirror 12 and the blue light in the green light, reflects green.The relay lens that is made of the first relay lens 14a and the second relay lens 14b for described red light and green light, is arranged in the light path of blue light of optical path length.Between first and second relay lenss, second catoptron 15 is set, it will change its working direction through the blue light emission of second dichronic mirror 13.In red light path and blue light path, dispose the 3rd catoptron 16a, the 4th catoptron 16b respectively, change the working direction of red light and blue light respectively, guiding is red with liquid crystal board 18R and the blue liquid crystal board 18B that uses respectively.In red light path, green light path and blue light path, dispose the second collimation lens 17a, the 3rd collimation lens 17b, the 4th collimation lens 17c respectively, with described first collimation lens, carry out ejaculation light with lamp 6 and on panel (back description) face, carry out action with the focus coupling.Red, blue, the green light that reflects respectively by above-mentioned the 3rd catoptron 16a, second dichronic mirror 13, the 4th catoptron 16b incides each red liquid crystal board 18R, green with liquid crystal board 18G, the blue liquid crystal board 18B that uses that uses.Redness makes up the first light incident side polarization plates 19a and the first emitting side polarization plates 20a with liquid crystal board 18R, shows red image.Similarly, green makes up the second light incident side polarization plates 19b and the second emitting side polarization plates 20b with liquid crystal board 18G, shows green image, and blueness makes up the 3rd light incident side polarization plates 19c and the 3rd with liquid crystal board 18B and penetrates lateral deviation vibration plate 20, shows blue image.Each light that penetrates from emitting side polarization plates 20a~c incides the dichroic prism 21 as optical modulator component.Dichroic prism 21 comprises red reflective film 22 and blue light reflectance coating 23.Then, reflect by red reflective film 22, penetrate to projecting lens (not shown) direction A by the light beam of redness with liquid crystal board 18R.In addition, reflect by blue light reflectance coating 23, penetrate to the direction A of projecting lens by the light beam of blueness with liquid crystal board 18B.By the light beam of green,, penetrate to projecting lens direction A equally by red reflective film 22 and blue light reflectance coating 23 with liquid crystal board 18G.And framework 25 is accommodated in its inside with above-mentioned each optics.
Fig. 3 is the figure that only extracts from the synoptic diagram of the structure of representing image forming source of the present invention 1 shown in Figure 2 about the present invention's part.In Fig. 3, the same parts of the symbolic representation identical with Fig. 2.In addition, in Fig. 2, the separately expression of red light path, green light path, blue light path, but because three light paths are basic identical, so not special separately expression in Fig. 3.Liquid crystal board 18 is made of TFT substrate 25 and counter substrate 26, by light incident side dustproof glass 27 and 28 protections of emitting side dustproof glass.The 60th, first angle of visibility that is provided with between liquid crystal board 18 and light incident side polarization plates 19 amplifies film, and the 61st, second angle of visibility that is provided with between described liquid crystal board 18 and emitting side polarization plates 20 amplifies film.First angle of visibility amplifies film 60, second angle of visibility, and to amplify film 61 for example be to apply collar plate shape (Discotic) liquid-crystal compounds on transparent support, carries out crosslinkedly, and generally, the angle of visibility that is used for the direct viewing type liquid crystal board amplifies, or equal product.
In order to improve contrast performance, has such example in the prior art: use coating collar plate shape liquid-crystal compounds on transparent support equally, carry out the crosslinked film that improves contrast.It is such technology, promptly utilizes the film that improves contrast respectively for the character of S ripple with its refractive index of P ripple different (indicatrixs), improves the orthogonality of the S ripple and the P ripple of liquid crystal board, improves contrast performance.But, use this technology also can improve contrast performance, but can not reduce the spot fault.This be because, in the projection type optical system, liquid crystal board needn't carry out the magnification field angling, it is important improving contrast performance, therefore, the film at the magnification field angle originally developed for the magnification field angle is used to improve contrast performance uses.The film at magnification field angle can be an identical materials with the film that improves contrast, but make in wide its contrast of angle of visibility scope nonreversible with respect to the film of making the magnification field angle, the film that making improves contrast makes the orthogonality of improving the S ripple and the P ripple of liquid crystal board in the Narrow Field Of Vision angular region, is inequality.That is, the film at employed magnification field angle is not a direction of improving contrast among the present invention, but revises light improving the angle of visibility direction.Importantly, improve the film of contrast, the light that does not leak tilted direction in complete black picture is cut by revision board like that, and is relative therewith, and the film correction image light at magnification field of the present invention angle makes that in complete white picture the light with tilted direction passes through revision board.
As one embodiment of the invention shown in Figure 3, if the film 60,61 that the magnification field angle is set a side or both sides (being the light incident side or the light emitting side of liquid crystal board 18) of liquid crystal board 18, the angle of visibility of liquid crystal board 18 is amplified, can relax the collimation of the ejaculation light of liquid crystal board 18.Therefore, as according to the present invention, can reduce the spot fault that is taken place by back projection type screen 3.
Fig. 4 is other embodiments of the invention.In Fig. 4, the same parts of the symbolic representation identical with Fig. 3.As aforementioned, liquid crystal board 18 is made of TFT substrate 25 and counter substrate 26, is protected by the dustproof glass 27 of light incident side and the dustproof glass 28 of emitting side.In the present embodiment, be characterised in that the fuzzy value of emitting side dustproof glass 28 is bigger than the fuzzy value of light incident side dustproof glass 27, these emitting side dustproof glass 28 usefulness are acted on scattering part with the image light scattering.Generally, to penetrate the transmitance of its dustproof glass all high in incident.But, under the situation that described spot fault takes place, also can establish the fuzzy value of emitting side dustproof glass 28 bigger as the present invention.
By like this, big through the scattering of light degree of liquid crystal board 18, can reduce the spot fault that is taken place by back projection type screen 3.The reason that can reduce the spot fault that is taken place by back projection type screen 3 is, incides the direction into the light of the diffusion material of the back projection type screen 3 of the reason of spot fault, upset by the generation source, is difficult to mutual interference.The spot fault also may take place at this emitting side dustproof glass 28, but since very near with the distance of the image displaying part of liquid crystal board, so almost no problem.But because polarization has been upset in scattering, so the contrast deterioration of image.Therefore, need obtain the balance that reduces spot fault and contrast deterioration, determine the fuzzy value of emitting side dustproof glass 28 simultaneously.In above-mentioned document 2 and 3 disclosed prior aries, only take some countermeasures, but, will the scattering of image light of spot fault own take place, make to break away from spot fault, more remarkable effect as the present invention in the screen side that the spot fault directly takes place.In order to strengthen the fuzzy value of emitting side dustproof glass 28, use and disperse the glass material of diffusion material to make, also can in bonding agent, disperse low refractive material simply, utilize spray-on process to apply it, on emitting side dustproof glass 28, make film.
Fig. 5 is other embodiments of the invention.In Fig. 5, the same parts of the symbolic representation identical with Fig. 4.Generally, because liquid crystal board 18 provides as universal component, so resemble the situation that special requirement has difficulties Fig. 4.In such, can resemble as shown in Figure 5, in the surperficial bonding of the emitting side dustproof glass 28 of liquid crystal board 18 or paste diffusion sheet 29 and use.If the cooling for liquid crystal board 18 has problem, make to have certain intensity in the diffusion sheet 29, be arranged between liquid crystal board 18 and the emitting side polarization plates 20 as other parts, also have same effect.
Fig. 6 is the figure of expression other embodiment of the present invention.In Fig. 6, the same parts of the symbolic representation identical with Fig. 4.In the present invention, be characterised in that the fuzzy value of emitting side polarization plates 20 is bigger than the fuzzy value of light incident side polarization plates 19, these emitting side polarization plates 20 usefulness are acted on dispersion image scattering of light parts.If mix diffusion material in polarization plates, its degree of polarization worsens, and does not increase but advantage is a component count.Also can be illustrated as Fig. 5, polarization plates and diffusion sheet are fitted.In this case, polarization plates is arranged on light incident side, diffusion sheet is arranged on emitting side, polarized light is not upset.
Fig. 7 is the figure of expression other embodiment of the present invention.In Fig. 7, the same parts of the symbolic representation identical with Fig. 4.In the present embodiment, be characterised in that, at the plane of incidence of dichroic prism 21, bonding or paste diffusion sheet 30 as scattering part.Diffusion layer leaves liquid crystal board 18, and resolution worsens, but because diffusion layer is in the outside of two polarization plates, so advantage is do not have to worsen contrast because polarized light is upset in the scattering that diffusion material causes.Make diffusion sheet 30 have certain intensity, be arranged between emitting side polarization plates 20 and the dichroic prism 21, also have identical effect as other parts.
Fig. 8 is the figure of expression other embodiment of the present invention.In Fig. 8, the same parts of the symbolic representation identical with Fig. 4.In the present embodiment, be characterised in that, at the outgoing plane of dichroic prism 21, bonding or paste diffusion sheet 31 as scattering part.Because diffusion layer further leaves liquid crystal board 18, so resolution worsens more, but the outgoing plane of dichroic prism 21 is general by red light, green light, blue light, so diffusion sheet 31 can be one.Make diffusion sheet 31 have certain intensity, be provided with as other parts and also have identical invention effect.
Fig. 9 is the figure of expression other embodiment of the present invention, is the synoptic diagram of expression as other structure of the image forming source 1 of image-displaying member use reflective liquid crystal plate.Ejaculation light from as the lamp 6 of light source incides the multi lens array that is made of light incident side multi lens array 7a and emitting side multi lens array 7b, and homogenized.Light beam from multi lens array passes through spectroscope 8, and its polarized light is consistent with the S polarized light, converges by collector lens 9 afterwards.Because first catoptron 10 and second catoptron 32 are used for the integral body of miniaturization image forming source 1, so will change its working direction from the beam reflection of collector lens 9.By the light that first catoptron 10 and second catoptron 32 are reflected, incide on first collimation lens 33, this first collimation lens 33 is used for the ejaculation light of lamp 6 is gone up and the focus coupling at panel (back description).Dichronic mirror 34 reflections see through blue light and green light from the red light in the light of first collimation lens 33.See through in the blue light and green light of this dichronic mirror 34, only blue light is the P polarized light by the first wavelength selectivity wavelength plate 35 from S polarized light polarisation transformation.The green light of S polarized light and polarisation transformation are the blue light of P polarized light, incide in first prism spectroscope 36.The green light of first prism spectroscope, 36 reflection S polarized lights, guiding green light reflective liquid crystal plate 38G, through the blue light of P polarized light, the blue reflective liquid crystal plate 38B that uses of guiding.On the other hand, the red light of the S polarized light that is reflected by described dichronic mirror 34 is by second prism spectroscope 37 secondary reflection again, the red reflective liquid crystal plate 38R that uses of guiding.
Optical modulator component 39 is to synthesize the prism spectroscope of using the image light of reflective liquid crystal plate 38B from redness with reflective liquid crystal plate 38R, the green reflective liquid crystal plate 38G of using and blueness.On the outgoing plane of second prism spectroscope 37,1/2 wavelength plate 40 is set.Incide in the red light of red light with the S polarized light of reflective liquid crystal plate 38R, image light is transformed to the P polarized light, sees through second prism spectroscope 37, is transformed to the S polarized light by above-mentioned 1/2 wavelength plate 40, incides prism spectroscope 39.The red light of prism spectroscope 39 reflection incidents penetrates to the B direction.In addition, incide in the green light of green light with the S polarized light of reflective liquid crystal plate 38G, image light is transformed to the P polarized light, sees through first prism spectroscope 36, also sees through prism spectroscope 39, penetrates to the B direction.Incide in the green light of blue light with the P polarized light of reflective liquid crystal plate 38B, image light is transformed to the S polarized light, by the reflection of first prism spectroscope 36, be that the second wavelength selectivity wavelength plate 41 of P polarized light is transformed to the P polarized light from S polarized light polarisation transformation by blue light only.Be transformed to the blue light of P polarized light, see through prism spectroscope 39, penetrate to the B direction.And framework 42 is accommodated in its inside with above-mentioned each optics.
Figure 10 is the figure that schematically shows the structure of employed reflective liquid crystal plate 38 in the embodiment of Fig. 9.In Fig. 9, red light with reflective liquid crystal plate 38G, blue light reflective liquid crystal plate 38B, has been used 3 with reflective liquid crystal plate 38R, green light, but 3 all basic identical, so not special the differentiation represented in Figure 10.In Figure 10, reflective liquid crystal plate 38 is made of display part 43 and transparency electrode 44, by dustproof glass 45 protections.Display part 43 is by silicon wafer 64, constituted catoptron 63, the liquid crystal 62 of surperficial asperitiesization.Generally, high more its performance of the reflectivity of catoptron 63 is good more, so catoptron 63 mirror-polishing as much as possible.But, under the situation that described spot fault takes place, as the present invention, with the surperficial asperitiesization of catoptron 63.By like this, big from the scattering of light change of reflective liquid crystal plate 38 ejaculations, can reduce the spot fault that is taken place by back projection type screen 3.
Figure 11 is the figure that only extracts from embodiment shown in Figure 9 about the present invention's part.In Figure 11, the same parts of the symbolic representation identical with Fig. 9.Respectively by display part 43R, 43G, 43B, transparency electrode 44R, 44G, 44B constitute red light, are protected by dustproof glass 45R, 45G, 45B with reflective liquid crystal plate 38B with reflective liquid crystal plate 38G, blue light with reflective liquid crystal plate 38R, green light.In the present embodiment, it is characterized in that the fuzzy value of this dustproof glass 45R, 45G, 45B is bigger than the fuzzy value of general dustproof glass, this dustproof glass 45R, 45G, 45B are used as scattering part.Strengthen the method for the fuzzy value of dustproof glass 45R, 45G, 45B, be for example to use to disperse the glass material of diffusion material to make, in bonding agent, disperse low refractive material on one side simply, utilize spray-on process to apply, the method for film forming on dustproof glass 45R, 45G, 45B.
Figure 12 is the figure of expression other embodiment of the present invention.In Figure 12, the same parts of the symbolic representation identical with Figure 11.Generally, has this situation, because reflective liquid crystal plate 38 provides as universal component, so resemble Figure 10 and special requirement as shown in Figure 11 is difficult.In such, as shown in Figure 12, can be on the surface of dustproof glass 45R, the 45G of reflective liquid crystal plate 38R, 38G, 38B, 45B bonding or paste diffusion sheet 46R, 46G, 46B use.Promptly in the present embodiment, be characterised in that, diffusion sheet 46R, 46G, 46B are used as scattering part.If aspect the cooling of reflective liquid crystal plate 38 problem is being arranged, also can make diffusion sheet 46R, 46G, 46B have certain intensity like this, as other parts, be arranged between reflective liquid crystal plate 38 and the prism spectroscope 36,37.Such formation also obtains the effect same with above-mentioned embodiment.
Figure 13 is the figure of other embodiment of the present invention.In Figure 13, the same parts of the symbolic representation identical with Figure 11.In the present embodiment, will be arranged on the emitting side of prism spectroscope 36,37 as the diffusion sheet 47 of scattering part.Because diffusion layer is in the back of the prism spectroscope 36,37 of separate picture light and unwanted light, so compare with the embodiment of Figure 12, has improved contrast performance.But diffusion layer leaves reflective liquid crystal plate 38, and resolution worsens.In the present embodiment, at the outgoing plane of 1/2 wavelength plate 40 and the bonding or stickup diffusion sheet 47 of outgoing plane of the second wavelength selectivity wavelength plate 41, also has identical effect but be arranged on plane of incidence side.In addition, make to have certain intensity in the diffusion sheet 47, also have identical effect as other parts setting.
Figure 14 is the figure of expression other embodiment of the present invention.In Figure 14, the same parts of the symbolic representation identical with Figure 11.Present embodiment is characterised in that, uses diffusion sheet 48 as scattering part, and this diffusion sheet 48 is bonding or paste on the outgoing plane of prism spectroscope 39.Because diffusion layer is in separate picture light and does not need the prism spectroscope 36,37 of light and the back of prism spectroscope 39, so compare with the embodiment of Figure 13, has further improved contrast performance.But, because diffusion layer is away from reflective liquid crystal plate 38, so resolution further worsens.
Various embodiment from Figure 10 to Figure 14 have been described above, but contrast performance, resolution, number of components etc. respectively there are relative merits, can investigate combination property and decide so which is implemented.
Figure 15 is that the synoptic diagram of mirror reflects type optical modulation element as embodiments of the present invention under the situation of the image-displaying member of image forming source 1 used in expression.Light beam from lamp 6 carries out homogenising by light pipe 49.Separate periodically by colour filter 50 from the light of light pipe 49 and to switch to redness, green, blue light.The light that is switched by colour filter 50 passes through collector lens 51, reflects by the catoptron 52 that is used for miniaturization image forming source 1 integral body, changes its working direction, guiding mirror reflects type optical modulation element 53.This mirror reflects type optical modulation element 53 is protected by dustproof glass 54, the bonding or stickup diffusion sheet 55 on its surface.Framework 56 is used to take in above-mentioned optics.Present embodiment is characterised in that with dustproof glass 54 or diffusion sheet 55, perhaps their combination is as scattering part.The mirror reflects type optical modulation element 53 of present embodiment, owing to do not use polarized light, diffusion sheet can be arranged on arbitrary position of the ejaculation direction of mirror reflects type optical modulation element 53, but as shown in Figure 15, is simple in the surperficial bonding of dustproof glass 54 or stickup.Though do not illustrate, each pixel all is made of tiny mirror in the mirror reflects type optical modulation element 53, so can asperitiesization carry out in the surface of each tiny mirror.Such formation is being used for the manufacturing of special requirement, and it is inconvenient carrying out correspondence, but owing to reduced by 2 scatterings, so at first reduced the deterioration of contrast performance.In addition, resolution does not worsen yet.
Above, be illustrated about in image-displaying member, using the situation of permeation type liquid crystal plate, reflective liquid crystal plate, mirror reflects type optical modulation element, but other image-displaying member is followed the principle that the spot fault reduces too.Therefore, under the situation of using other image-displaying member, be also contained in the scope of the present invention.