CN1756988A - A display device and an illumination system therefor - Google Patents

According to defined invention in the

1, can partly realize above-mentioned at least and other target.Therefore, the present invention has instructed a kind of like this display device, this display device comprises: display panel and illuminator, described display panel comprises electro-optical material layer, first light transmissive substrate of the electrode of arranging with row and column is equipped with at pixel region, second light transmissive substrate, described electro-optical material layer is clipped between described first and second layers, described illuminator is disposed on second substrate side away from described electro-optical material layer, this illuminator comprises the optical waveguide of light transparent materials, described optical waveguide has the exit facet towards described display panel, it is characterized in that described illuminator also comprises matrix-addressable light-management member, all like matrix-addressable output coupling units.Like this, the light of light source generation just can be distributed on the display panel in more effective mode.Therefore, the contrast of display can be improved, and the part that can realize lighting device strengthens and weaken the part.Compatibly, described matrix-addressable light-management member comprises liquid crystal material layer, row electrode layer and row electrode layer, and described liquid crystal material layer is clipped between described row electrode layer and the described row electrode layer, and preferred described liquid crystal material layer is made of liquid crystal gel material.Term " liquid crystal gel material " should be understood to a kind of like this material in this article, this material is to apply after voltage makes that monomer-polymer changes high scattering state into from pellucidity, the material that the photopolymerization by liquid crystal and polyfunctional group liquid crystal monomer under the situation that light trigger exists forms.Preferred described illuminator also comprises a light source, described light source is disposed in one side at least of described matrix-addressable output coupling unit, the observer of display device sees as described, be arranged in the dorsal part of described matrix-addressable output coupling unit, or the observer of display device sees as described, is arranged in the front side of described matrix-addressable output coupling unit.

1 comprises

2 and

3 substantially.

As shown in Figure 1,

2 comprises electro-optically active material (such as liquid crystal material) layer 4 substantially.Under the situation that is liquid crystal layer, the ferroelectric effect that the work of described layer commutates and is listed as (IPS) or is used to modulate its glazing incident polarised direction to row (VAN), light compensated birefringence (OCB), plate inscribe based on for example twisted nematic (TN), STN Super TN (STN), homeotropic alignment.Described electro-optically active layer 4 is clipped between first and

5,6.In addition, described display panel is subdivided into voxel model, described electrode substantial transparent by a plurality of forward and backward electrodes (7,8) (for example, being arranged in the electrode in the matrix pixel style on described

5 and

6).Preferably use driven with active matrix in this case.

5 and

6 are made by light transmitting material, and same as above,

7 also is light transmissive and can be made by for example tin indium oxide (ITO).By connecting

9,10,

7,8 is connected to

11 to provide an electric driving voltage on described

7,8, and described driving voltage is by described

11 controls.In addition, display panel also comprises the

12 and

13 with known way own usually.

Illuminator 3 (see figure 2)s that the present invention relates generally to comprise

14 substantially, and compatibly comprise four end faces (end face) 16, and described

14 has the

15 that is configured to towards described display panel 2.Light source 17 (all like excellent type fluorescent lights) is disposed on the one side at least of described

16, and the light by described

16 described light emitted is configured to be coupled to waveguiding structure 14.Be equipped with reflectance coating etc. can for the

14 all faces except input coupling (incoupling)

16 and

15, penetrate waveguide to prevent the position that light is never expected.

According to the first embodiment of the present invention, described

14 consists essentially of liquid

18, and this liquid crystal material layer is clipped between

19 and second waveguide substrate 20.By on described

18, applying voltage, can between pellucidity and scattering state, modulate liquid crystal material.In addition, by before a plurality of and back

21 and 22 described waveguides be subdivided into voxel model, described before and back

21 and 22 be disposed in the matrix pixel style on described

19 and described second waveguide substrate 20.Therefore, said structure has constituted matrix-addressable light-management member, and the pixel of liquid

19 is changed between transmissive state and scattering state by addressing

21,22, when being in described transmissive state, pixel only transmission subsequently in

14 by the light of internal reflection, and when being in scattering state, therefore light allowed to pass the

15 of

14 towards

2 direction transmitted lights by the pixel scattering.In this example, matrix-addressable light-management member is the output coupling unit.But described lighting device comprises a plurality of light-management members, such as the operable output coupling unit of the present invention, reflection, scattering and redirection component.The resolution of waveguide pixel pattern can be preferably than big or big many of the resolution of

2 respective pixel patterns.Waveguide

21 and 22 is connected to

11 so that an electric driving voltage to be provided by connecting

23 and 24 on described

21 and 22, this driving voltage is by described

11 controls.Alternative scheme is to provide an independent driver element to drive described matrix waveguide.Preferred

21 and 22 is a band electrode, therefore can be known as row electrode and column electrode respectively.By the row and column electrode package being contained in the waveguiding structure and controlling the voltage that is applied on the electrode, can change the scattering number of times of scattering liquid crystal gel layer on the lighting device surf zone, and make waveguide light is projected to the position that needs.Therefore, by in display device, comprising such lighting device, a large amount of light can be injected the zone that will show the highlights branch on the indicator screen of display device, and light (or not having light) is injected the zone that will show the dark-part on the indicator screen of display device in a small amount.Therefore, can improve display high-high brightness and black level (thereby improving contrast).In addition, compare,, therefore can reduce power consumption because the dark-part that does not almost have light to be shown device absorbs with the prior art LCD.

Above-mentioned

14 can be glued or by other means fastened to a thicker photoconduction, for further strengthening brightness backlight, as mentioned above, can arrange reverberator or reflectance coating, arrange in the front side of waveguiding structure and be redirected sheet metal at the dorsal part of waveguiding structure.

At first, provide

60 that the image that shows on

2 is provided by picture material.Send picture material to

61, in described

61, which part of image is bright to find out, which part is dark to analyze described picture material.Use this information, control described

3 and display panel 2.Therefore, analyzed picture material is transferred into display

62, this display

62 is set makes its control be applied to signal on the

7,8.Analyzed picture material is transferred into

63 equally, in this

63, picture material is processed and may be converted into illuminator pixel form, and the

21,22 that is transferred into

3 subsequently is to control its scattering.But the backlight intensity of illuminator means in a certain zone of other area change relatively, and the gray-scale value of the image that will show at

2 also needs to change, and the change of described gray-scale value can realize by display

62.

Disclosed in WO 02/21042 as picture,

3 can combine the function of highlight with scanning backlight according to the present invention.For example hypothesis is lighted delegation at every turn, just can realize above-mentioned function combination.Because liquid crystal gel material is more faster than common LC material response, therefore use the standard passive matrix addressing can realize line scanning.Be in the state of opening (on) in the capable addressing time of only being expert at, rather than the root-mean-square value (RMS) of signal is responded.Because row by sequential addressing, therefore can be lighted delegation at every turn.

Described drive arrangement is relevant with the processing details of material behavior and scattering liquid crystal gel material, will introduce more in detail below.Fig. 4 shows described lighting device or typical electro-optical response curve backlight.The absolute value of voltage difference between the row and column electromotive force that described liquid crystal gel material applies in response to driver element 11.Liquid crystal gel material has the response time of 1ms level.As Fig. 4 as can be seen, there is a threshold voltage, material substantially transparent when being lower than this threshold voltage, and the output of the light of

3 is low.The same with the ordinary passive matrix addressing, this threshold value can be used for selecting row.In this case, can use the row of 60V to select voltage, and column signal can change (be in the state of opening (on), be in closed condition) at-30V to the scope the between+30V at 30 o'clock at+30 o'clock.If capable selected, then the pixel bias voltage is 30V to the maximum, and when selecting row, the pixel bias voltage can change between 30V to 90V.Fig. 5 schematically shows this driving method.

Hereinafter use description to the addressing scheme of a kind of modification of above-mentioned open display device.By increasing capable select time the light output of described

3 is increased.Can realize the increase of row select time by the strobe pulse of overlapping continuous row, and not reduce the resolution of matrix structure, see Fig. 6.But, do like this or some consequences arranged.Owing at a time in time selected row, therefore no longer may give the value of each pixel any desired more than delegation.If use identical row or data-driven as mentioned above, then lighting device or backlight on the optical mode that illustrates will trail along column direction (smear).The number of hangover depends on the number of the row of selecting simultaneously.But, because this situation just has influence on lighting device, do not have the whole display device that influences, therefore consider this hangover situation of luminance gain or acceptable.In addition, by pre-service (for example) lighting device lighting pattern, can offset hangover to a certain extent along column direction by high-pass filtering along column direction.

Display device 31 consists essentially of

32 and

33.

Described

32 is basic identical with the display panel in the above-mentioned example, thereby no longer does detailed description herein.

33 comprises

25 and

26 substantially.Described

25 can be the standard form that produces constant polarisation level (bias light level).Described

26 be arranged in described

25 and

32 between.In this case, described

26 consists essentially of electro-optically active layer 34 (seeing Fig. 8, such as liquid crystal layer), and this electro-optically

34 is addressed by the preceding and rear electrode that has above described in detail.Described electro-optically active layer with respective addressed device is clipped between first and

35,36.Said structure comprises matrix-addressable light-management member.Therefore, the electro-optically

34 of described

26 is configured to modulate the light that is penetrated by

25, and described

35,36 be used to reuse have the light that does not need polarization or be transmitted to be shown image that device shows " dark;; the light of part, as shown in Figure 8.Like this, can improve efficient backlight.Fig. 9 schematically shows the driving of the type display device.Herein, display image on described display device.For example, the information about image that will be shown (being picture material) by the acceptance such as vision signal that

60 is provided from picture material.Thereafter, picture material is transmitted to

61, is used for the picture material of the bright and/or dark-part of analysis image.Thereafter utilize this graphical analysis information to form and handled picture signal, this has been handled picture signal and has been transmitted to display

2, and this graphical analysis information is configured to control the image demonstration of display panel 2.In addition, also utilize graphical analysis information to form 2D backlight information signal in the

62, this 2D backlight information signal is set makes it according to the transmission about the information Control backlight modulator of the bright and/or dark-part of image that will show.In addition, this 2D backlight information signal also is transferred into the bias level modulator 64 that is used to modulate bias level signal, and the bias level that this bias level modulator 64 makes its control

25 is set.

Figure 10 discloses an alternate embodiments.Herein, described

41 comprises

42 and illuminator 43 substantially.

Described

42 is basic identical with the display panel in the foregoing description, thereby will not be described in detail herein.

Illuminator 43 comprises the basic

45 that is used for bias level illumination and substantially substantially with the scattering modulator panel of opening in 45 minutes backlight 44.Described

45 are clipped between described

42 and the

44 basically.

Described

45, consist essentially of

46, described

46 has

47,

48, and compatibly comprises four

49, arrange described

47 towards described

42, arrange that described

48 is towards described modulator panel 44.At least one end face along described

49 is arranged light source 50 (all like excellent type fluorescent lights), and the light that is provided with by described light emitted makes it be coupled to waveguiding

46 by described end face 49.All faces of

46 except that input

49,

47,48 all can be equipped with reflectance coating etc., penetrate waveguide with the position that stops light never to be expected.Described

46 can have a conical in shape, also can be equipped with

57 grades to obtain to be used for the reflective-mode that is fit to of waveguide.

Constitute the

44 of matrix-addressable light-management member, consist essentially of the liquid crystal

51 that is clipped between

52 and second substrate 53.In addition, described

44 is subdivided into voxel model by before a plurality of and the rear electrode (not shown) again such as band electrode, described a plurality of before and rear electrode be arranged to matrix pixel style on described

52 and second substrate 53.The same, the resolution of described scattering modulator panel voxel model is littler or much smaller than

42 corresponding resolution.In addition, described illuminator also is equipped with

56, arranges that this

56 is clipped between described

56 and

45

44.

Hereinafter will introduce the function of present embodiment.Light is passed

49 and is entered

46 by

50

46 inside, light by pyramidal structure and

57 by internal reflection so that light only passes basically towards

48 of

44 penetrates.As above

44 to make some pixels be in transparent mode according to the image that will be shown

42 demonstrations, some pixels are in backscatter mode.Therefore, the light that enters transparent pixels will pass transparent pixels by transmission, be reflected by

56 then, get back in the waveguiding structure.On the other hand, the light that enters the scattering pixel will be scattered along the direction of waveguiding structure and do not reflected by

56.

The embodiment of Figure 11 corresponds essentially to disclosed embodiment among Fig. 3, thereby will no longer repeat the basic function of display herein.But according to present embodiment, described display also comprises lamp driver/light source power modulator 29.Power for the lamp by lamp driver 29

3 must produce needed signal.Analysis will be shown the image that panel shows, and draws intensity level backlight thus.The illuminated

63 of described subsequently intensity level is divided into the modulation signal and the light source power modulation of the scattering power of modulation middle LC gel backlight.For fully accurately, can require to comprise feedback loop, this feedback loop comprises one or more measurement actual lamp outputs and the optical sensor 28 that compares with needed output.Figure 11 schematically shows described process.Optical sensor 28 detected signals are set it is fed back to described lamp driver 29, described lamp driver 29 also is connected to receive the information from illuminator control module 63.Therefore, the power that offers pixel will change according to the picture material that is shown by pixel.Therefore, change light source power when just being addressed, can improve the contrast of display by segmented backlight.(just in scattering) power source will have power pi when section i just is being addressed, and when section j during just in scattering power source have power pj.According to the needed brightness regulation power of section I pi, the average power of

3 lamp should be steady state value.By present embodiment, can realize having contrast raising, peak brightness raising, the better display device of colouristic properties.

1. a display device (1) comprising:

-display panel (2), described display panel (2) has electro-optical material layer (4); First light transmissive substrate (5) of the electrode of arranging with row and column (7) is equipped with at pixel region; Second light transmissive substrate (6), described electro-optical material layer (4) be clipped between described first and second substrates (5,6) and

-illuminator (3), described illuminator (3) is disposed in the last side away from described electro-optical material layer (4) of second substrate (6), described illuminator comprises the optical waveguide (14) of light transparent materials, and described optical waveguide (14) has the exit facet (15) towards described display panel (2)

It is characterized in that,

Described illuminator (3) also comprises matrix-addressable light-management member (27).

2. the described display device of claim 1, wherein said matrix-addressable light-management member is the output coupling unit (27) that comprises liquid crystal material layer (18), row electrode layer (21) and row electrode layer (22), and described liquid crystal material layer (18) is clipped between described row electrode layer (21) and the described row electrode layer (22).

3. the described display device of claim 2, wherein said liquid crystal material layer (18) is made of liquid crystal gel material.

4. each described display device of aforementioned claim, wherein illuminator (3) also comprises light source (17), described light source (17) is disposed in one side at least of described matrix-addressable output coupling unit (27), the observer of display device sees as described, be arranged in the dorsal part of described matrix-addressable output coupling unit (27), or the observer of display device sees as described, is arranged in the front side of described matrix-addressable output coupling unit (27).

5. each described display device of aforementioned claim, also comprise driver element (11), this driver element (11) makes the image that its analysis will show on described display panel bright and dark-part is set, determine the light illumination mode that will be shown by described display device in view of the above, and produce the drive signal that is fit to substantially simultaneously and give the saltus step of not expecting in illumination that described display panel (2) produces because of light illumination mode with compensation or the color.

6. the described display device of claim 5, wherein said driver element (11) is configured to the addressing strobe pulse is offered the continuous substantially addressing band of illuminator electrode, make that for this reason the select time ratio of described strobe pulse is long divided by the frame time of addressing band quantity, thereby will make the strobe pulse of sequential addressing band overlapping.

7. the described display device of claim 5, wherein said driver element (11) is configured to provide simultaneously the two or more addressing bands of addressing strobe pulse to described illuminator electrode.

8. each described display device of aforementioned claim also comprises the bias level modulator (64) of the bias level that is configured to control described illuminator.

9. each described display device of aforementioned claim also comprises the light source power modulator (29) of the light source power that is used to modulate described illuminator (3), and this modulation depends on the shown light illumination mode of described lighting device.

10. the described display device of claim 9 wherein saidly comprises a kind of in cold-cathode fluorescence lamp, hot-cathode fluorescent lamp, white luminous diode or the combination of colorful light-emitting diode with modulated light source.

11. each described illuminator of aforementioned claim 1-10 is applicable to aforementioned each described display device of right claim 1-10.

12. the method for each described driving display device of aforementioned claim 1-10 may further comprise the steps:

-analysis will be shown the bright and dark-part of the image of panel (2) demonstration,

-will become to be suitable for the resolution of described lighting device (3) about the information translation of the bright and dark-part of analyzed image,

-will send lighting device (3) about the information of analyzed image to,

-will convert the resolution that is fit to described display panel (2) about the activation bit of described lighting device (3) to, one of the color that causes by light illumination mode with compensation and brightness do not expect saltus step and

-by the described information-driven lighting device (3) that has been converted.