Display device and control method for display device

Abstract

To provide a display device capable of efficiently detecting degradation of a liquid crystal panel.SOLUTION: A display device comprises: a light source; a liquid crystal panel including a display region on which light emitted from the light source is incident, the display region having a first substrate and a second substrate provided facing each other, and a liquid crystal layer between the first substrate and the second substrate, and a peripheral region in periphery of the display region; a light irradiation section that irradiates a portion of the liquid crystal layer overlapping the peripheral region with light of a first wavelength band, as viewed in a normal direction of the first substrate; and a light detection section that detects light of a long wavelength band longer than the first wavelength band emitted from the portion of the liquid crystal layer when the light irradiation section irradiates the portion of the liquid crystal layer with the light of the first wavelength band.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a display device and a method for controlling the display device. [Background technology]

[0002] In projection display devices, light emitted from a light source is irradiated onto a transmissive or reflective liquid crystal panel, and the transmitted or reflected light is modulated by the liquid crystal panel and projected onto a screen. Such display devices are prone to deterioration due to the high intensity of light emitted from the light source to the liquid crystal panel.

[0003] For example, Patent Document 1 describes a liquid crystal display device that uses an optical sensor to detect the chromaticity or illuminance of a light beam emitted from a liquid crystal panel, and controls a cooling means by determining the image quality state of an optical image based on the detection results. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-40016 Summary of the Invention [Problem to be solved by the invention]

[0005] In such display devices, it is desirable to efficiently detect deterioration of the liquid crystal panel. [Means for solving the problem]

[0006] One aspect of the display device according to the present invention is A light source and a liquid crystal panel having a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel including a display area into which light emitted from the light source is incident, and a peripheral area around the display area; a light irradiation unit that irradiates a portion of the liquid crystal layer that overlaps with the peripheral region when viewed from a normal direction of the first substrate with light in a first wavelength range; a light detection unit that detects light in a wavelength range longer than the first wavelength range that is emitted from the portion of the liquid crystal layer when the light irradiation unit irradiates the portion of the liquid crystal layer with light in the first wavelength range; It has.

[0007] One aspect of the display device control method according to the present invention includes: A light source and a liquid crystal panel having a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel including a display area into which light emitted from the light source is incident, and a peripheral area around the display area; a light irradiation unit that irradiates a portion of the liquid crystal layer that overlaps with the peripheral region when viewed from a normal direction of the first substrate with light in a first wavelength range; A method for controlling a display device having When the light irradiation unit irradiates the portion of the liquid crystal layer with light in the first wavelength range, the light irradiation unit detects light in a wavelength range longer than the first wavelength range that is emitted from the portion of the liquid crystal layer. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically showing a display device according to a first embodiment. [Figure 2] FIG. 1 is a plan view schematically showing a liquid crystal panel of a display device according to a first embodiment. [Figure 3] FIG. 1 is a cross-sectional view schematically showing a liquid crystal panel of a display device according to a first embodiment. [Figure 4] FIG. 1 is a plan view schematically showing a display device according to a first embodiment. [Figure 5] FIG. 1 is a cross-sectional view schematically showing a display device according to a first embodiment. [Figure 6] 10 is a graph for explaining the change over time in photoluminescence when blue light is irradiated onto a liquid crystal layer. [Figure 7]10 is a graph for explaining changes in photoluminescence over time in an accelerated deterioration test of a liquid crystal panel. [Figure 8] 10 is a graph for explaining changes in photoluminescence over time in an accelerated deterioration test of a liquid crystal panel. [Figure 9] 4 is a graph for explaining the electro-optical characteristics of a liquid crystal panel. [Figure 10] 5 is a flowchart for explaining processing by a control unit of the display device according to the first embodiment. [Figure 11] FIG. 10 is a cross-sectional view schematically showing a display device according to a modified example of the first embodiment. [Figure 12] FIG. 10 is a plan view schematically showing a display device according to a second embodiment. [Figure 13] FIG. 10 is a cross-sectional view schematically showing a display device according to a second embodiment. [Figure 14] FIG. 10 is a cross-sectional view schematically showing a display device according to a modified example of the second embodiment. [Figure 15] FIG. 10 is a plan view schematically showing a display device according to a third embodiment. [Figure 16] FIG. 11 is a plan view schematically showing a display device according to a modified example of the third embodiment. [Figure 17] FIG. 11 is a plan view schematically showing a display device according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0010] 1. First embodiment 1.1. Display device 1.1.1. Overall structure First, a display device 100 according to a first embodiment will be described with reference to the drawings. Fig. 1 is a diagram schematically showing the display device 100 according to the first embodiment.

[0011] 1, the display device 100 includes, for example, a light source 10, dichroic mirrors 20 and 22, reflecting mirrors 24, 26, and 28, light modulation devices 30R, 30G, and 30B, a cross dichroic prism 40 as a light combining device, and a projection device 50. The display device 100 is, for example, a 3LCD (Liquid Crystal Display) type projector.

[0012] The light source 10 is, for example, a lamp unit configured from an array light source having a semiconductor laser, or a white light source such as an ultra-high pressure mercury lamp or a halogen lamp. Although not shown, an integrator lens may be provided to improve the uniformity of the light emitted from the light source 10.

[0013] Dichroic mirror 20 transmits red light (R) and reflects green light (G) and blue light (B) out of the light emitted from light source 10. Dichroic mirror 22 reflects the green light (G) reflected by dichroic mirror 20 and transmits the blue light (B).

[0014] The red light (R) reflected by the dichroic mirror 20 is reflected by the reflecting mirror 24 and then The green light (G) reflected by the dichroic mirror 22 is incident on the light modulation device 30R. The blue light (B) transmitted through the dichroic mirror 22 is incident on the light modulation device 30B via the reflecting mirrors 26 and 28.

[0015] The light modulation devices 30R, 30G, and 30B are disposed facing the light incident surfaces of the cross dichroic prism 40 for the respective color lights. The light modulation devices 30R, 30G, and 30B each include a liquid crystal panel 32, a first polarizing element 34, and a second polarizing element 36. The liquid crystal panel 32 is disposed between the first polarizing element 34 and the second polarizing element 36. The liquid crystal panel 32 modulates the incident color light based on video information (video signal). The first polarizing element 34 controls the polarization of the light incident on the liquid crystal panel 32. The second polarizing element 36 controls the polarization of the light incident from the liquid crystal panel 32. The color lights modulated by the light modulation devices 30R, 30G, and 30B are each emitted toward the cross dichroic prism 40. Details of the liquid crystal panel 32 will be described later.

[0016] The cross dichroic prism 40 is made up of four bonded right-angle prisms, each with a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light arranged in a cross shape on its inner surface. These dielectric multilayer films combine the three colored lights to generate light that represents a color image. The light combined by the cross dichroic prism 40 is emitted toward the projection device 50.

[0017] The projection device 50 projects the incident combined light onto a screen 60. An enlarged image is displayed on the screen 60. The projection device 50 is formed of, for example, a projection lens.

[0018] In addition to projectors, the display device 100 can be applied to various electronic devices such as liquid crystal panels for photocuring 3D printers, EVFs (Electrical View Finders), mobile mini projectors, head-up displays, smartphones, mobile phones, mobile computers, digital cameras, digital video cameras, displays, in-vehicle equipment, audio equipment, exposure equipment, and lighting equipment.

[0019] 1.1.2. LCD panel Fig. 2 is a plan view schematically showing the liquid crystal panel 32. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2, schematically showing the liquid crystal panel 32.

[0020] The liquid crystal panel 32 is an active-drive liquid crystal device having a thin film transistor (TFT) as a transistor for each pixel. As shown in Figures 2 and 3, the liquid crystal panel 32 has, for example, an element substrate 110, a sealant 120, a liquid crystal layer 130, and an opposing substrate 140.

[0021] As shown in FIG. 2, the element substrate 110 is larger than the counter substrate 140 when viewed from the normal direction of the element substrate 110 of the light modulation device 30B (hereinafter simply referred to as "viewed from the normal direction"). The planar shape of the element substrate 110 is, for example, a rectangle. In the example shown in FIG. 3, the normal direction is the direction in which a normal N to the surface of the first support substrate 112 of the element substrate 110 facing the liquid crystal layer 130 extends, which is the Z-axis direction. In the example shown, the normal direction is the stacking direction of the element substrate 110 and the liquid crystal layer 130.

[0022] The sealant 120 bonds the element substrate 110 and the counter substrate 140. The sealant 120 is provided along the outer edge of the counter substrate 140. When viewed from the normal direction, the sealant 120 surrounds the liquid crystal layer 130. The sealant 120 is, for example, an adhesive such as a thermosetting, photosetting, or electron beam setting epoxy resin. A display area 2 including a plurality of pixels P arranged in a box shape is provided. The display area 2 is surrounded by a peripheral area 4. In the peripheral area 4, a parting portion 142 is provided between the sealant 120 and the display area 2, surrounding the display area 2. The parting portion 142 is made of a material such as a light-blocking metal or metal oxide.

[0023] The element substrate 110 includes, for example, an external connection terminal 101, a data line driving circuit 102, an inspection circuit 103, a scanning line driving circuit 104, a first wiring 105, and a second wiring 106.

[0024] A plurality of external connection terminals 101 are provided. In the illustrated example, the plurality of external connection terminals 101 are arranged in the X-axis direction. The data line driving circuit 102 is provided between a first side along the plurality of external connection terminals 101 and the sealing material 120. The inspection circuit 103 is provided between the display area 2 and the sealing material 120 along a second side opposite to the first side. The scanning line driving circuit 104 is provided between the display area 2 and the sealing material 120 along third and fourth sides perpendicular to the first side and opposite to each other. Although not illustrated, the inspection circuit 103 may be provided between the display area 2 and the sealing material 120 along the data line driving circuit 102.

[0025] The first wiring 105 is provided between the sealant 120 along the second side and the inspection circuit 103. The first wiring 105 is connected to two scanning line driving circuits 104. A plurality of first wirings 105 are provided. The second wiring 106 is connected to the data line driving circuit 102 and the scanning line driving circuit 104. The second wiring 106 is electrically connected to a plurality of external connection terminals 101. A plurality of second wirings 106 are provided.

[0026] As shown in FIG. 3, the element substrate 110 includes, for example, a first support substrate 112, pixel electrodes 114, TFTs 116, and a first alignment layer 118.

[0027] The first support substrate 112 supports the pixel electrodes 114, the TFTs 116, and the first alignment layer 118. The first support substrate 112 is, for example, a glass substrate, a quartz substrate, etc. The first support substrate 112 transmits light emitted from the light source 10.

[0028] The pixel electrodes 114 and the TFTs 116 are provided on the liquid crystal layer 130 side of the first support substrate 112. A pixel electrode 114 and a TFT 116 are provided for each pixel P. A plurality of pixel electrodes 114 and TFTs 116 are provided corresponding to a plurality of pixels P. The pixel electrodes 114 and the TFTs 116 constitute a pixel P. The pixel electrodes 114 are transparent electrodes made of, for example, ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The TFTs 116 are switching elements.

[0029] The first alignment layer 118 is provided on the liquid crystal layer 130 side of the first support substrate 112. The first alignment layer 118 covers the first support substrate 112, the pixel electrodes 114, the TFTs 116, and the first wiring 105. The first alignment layer 118 is, for example, an inorganic alignment layer such as a silicon oxide layer, or an organic alignment layer such as a polyimide layer.

[0030] The liquid crystal layer 130 is provided between the element substrate 110 and the counter substrate 140. The liquid crystal layer 130 is formed by sealing liquid crystal having positive or negative dielectric anisotropy in the gap between the element substrate 110 and the counter substrate 140.

[0031] The counter substrate 140 is provided on the side of the liquid crystal layer 130 opposite to the element substrate 110. The counter substrate 140 faces the element substrate 110. Light emitted from the light source 10 is incident on the counter substrate 140.

[0032] The counter substrate 140 includes, for example, a second support substrate 141, a parting portion 142, an insulating layer 143, a counter electrode 144, and a second alignment layer 145.

[0033] The second support substrate 141 faces the first support substrate 112. The second support substrate 141 supports the parting portion 142 and the insulating layer 143. The second support substrate 141 is, for example, a glass substrate or a quartz substrate. The second support substrate 141 transmits light emitted from the light source 10. When viewed from the normal direction, the area of ​​the second support substrate 141 is smaller than the area of ​​the first support substrate 112, for example.

[0034] The parting portion 142 is provided on the liquid crystal layer 130 side of the second support substrate 141. As shown in FIG. 2, the parting portion 142 overlaps with the inspection circuit 103 and the scanning line driving circuit 104 when viewed from the normal direction. The parting portion 142 blocks light incident from the counter substrate 140 side from entering peripheral circuits such as the inspection circuit 103 and the scanning line driving circuit 104. This makes it possible to suppress malfunctions of the peripheral circuits. Furthermore, the parting portion 142 reduces the incidence of unnecessary stray light into the display area 2. This makes it possible to suppress a decrease in the contrast of the liquid crystal panel 32.

[0035] As shown in FIG. 3, the insulating layer 143 is provided on the liquid crystal layer 130 side of the second support substrate 141. The insulating layer 143 covers the parting portion 142. The insulating layer 143 is provided between the liquid crystal layer 130 and the second support substrate 141. The surface of the insulating layer 143 on the liquid crystal layer 130 side is, for example, a flat surface. The insulating layer 143 transmits light emitted from the light source 10. The insulating layer 143 is, for example, a silicon oxide layer.

[0036] The counter electrode 144 is provided on the liquid crystal layer 130 side of the insulating layer 143. The counter electrode 144 is provided between the liquid crystal layer 130 and the insulating layer 143. The counter electrode 144 is a transparent electrode made of, for example, ITO or IZO.

[0037] The second alignment layer 145 is provided on the liquid crystal layer 130 side of the counter electrode 144. The liquid crystal layer 130 is provided between the first alignment layer 118 and the second alignment layer 145. The second alignment layer 145 is, for example, an inorganic alignment layer such as a silicon oxide layer, or an organic alignment layer such as a polyimide layer.

[0038] The liquid crystal panel 32 employs optical designs for a normally white mode or a normally black mode. In the normally white mode, the transmittance of the pixel P when no voltage is applied is greater than the transmittance when a voltage is applied. In the normally black mode, the transmittance of the pixel P when no voltage is applied is less than the transmittance when a voltage is applied.

[0039] In the example shown in FIG. 1, the liquid crystal panel 32 is of a transmissive type, but it may be of a reflective type.

[0040] 1.1.3. Deterioration substances in the liquid crystal layer, light irradiation section, and light detection section Fig. 4 is a plan view schematically showing the display device 100. Fig. 5 is a cross-sectional view taken along line VV in Fig. 4, schematically showing the display device 100. For convenience, Figs. 4 and 5 omit illustration of components other than the liquid crystal panel 32, light irradiator 70, and light detector 80 of the light modulation device 30B into which blue light is incident. For convenience, Fig. 4 also shows a simplified illustration of the liquid crystal panel 32.

[0041] 4 and 5, the display device 100 has a light emitting section 70 and a light detecting section 80. The liquid crystal layer 130 has a first portion 132 and a second portion 134.

[0042] The first portion 132 of the liquid crystal layer 130 is a portion that overlaps with the display area 2 of the liquid crystal panel 32 when viewed from the normal direction. Light emitted from the light source 10 is incident on the display area 2. The shape of the first portion 132 when viewed from the normal direction is, for example, a rectangle. Blue light BL emitted from the light source 10 is incident on the first portion 132.

[0043] The second portion 134 of the liquid crystal layer 130 is a portion that overlaps with the peripheral region 4 of the liquid crystal panel 32 when viewed from the normal direction. The peripheral region 4 is a region surrounding the display region 2. The liquid crystal panel 32 has the display region 2 and the peripheral region 4. When viewed from the normal direction, the peripheral region 4 is a region that is outside the inner edge 142a of the parting portion 142 that serves as a light-shielding layer. The inner edge 142a is the boundary between the peripheral region 4 and the display region 2. The peripheral region 4 is a non-display region where no image is displayed. The parting portion 142 has, for example, a plate-like shape. The second portion 134 is continuous with the first portion 132.

[0044] As shown in FIG. 5 , the first portion 132 of the liquid crystal layer 130 is irradiated with blue light BL from the light source 10 for a certain period of time, causing a liquid crystal degradation product 136 to be generated. When irradiated with the blue light BL, the liquid crystal degradation product 136 emits light PL. The light PL is light with a longer wavelength than the blue light BL. The wavelength of the light PL is, for example, 550 nm or more and 650 nm or less. The wavelength of the light PL may be 600 nm or more and 650 nm or less. The wavelength of the blue light BL is, for example, 430 nm or more and 490 nm or less. The light PL is, for example, red light. The light PL is fluorescence in the liquid crystal degradation product 136. More specifically, the light PL is photoluminescence (phosphorescence) in the liquid crystal degradation product 136. The light PL is emitted approximately isotropically from the liquid crystal degradation product 136.

[0045] The liquid crystal degradation products 136 generated in the first portion 132 of the liquid crystal layer 130 diffuse to the second portion 134 of the liquid crystal layer 130. The white arrows in FIG. 4 indicate the diffusion of the liquid crystal degradation products 136 from the first portion 132 to the second portion 134. In the graph of FIG. 4, the horizontal axis indicates the position on the liquid crystal panel 32, and the vertical axis indicates the emission intensity of light PL from the liquid crystal degradation products 136. The emission intensity on the vertical axis is equivalent to the concentration of the liquid crystal degradation products 136, and the liquid crystal degradation products 136 diffuse from the first portion 132, which has a high concentration, to the second portion 134, which has a low concentration. Because the second portion 134 is not irradiated with blue light BL from the light source 10, the liquid crystal degradation products 136 present in the second portion 134 do not emit light PL due to the blue light BL.

[0046] The light irradiating unit 70 irradiates the second portion 134 of the liquid crystal layer 130 with light IL. This causes the liquid crystal degradation products 136 present in the second portion 134 to emit light PL. The light detecting unit 80 detects the light PL emitted from the second portion 134 when the light irradiating unit 70 irradiates the second portion 134 with light IL.

[0047] The light irradiation unit 70 overlaps with the second portion 134 of the liquid crystal layer 130 when viewed from the normal direction. The light irradiation unit 70 is provided on the counter substrate 140 as shown in FIG. 5. The light irradiation unit 70 is provided, for example, on the opposite side of the counter substrate 140 from the liquid crystal layer 130. In the example shown in the figure, the light irradiation unit 70 is provided on the surface of the counter substrate 140 facing the +Z axis direction. The light irradiation unit 70 is, for example, an LED (Light Emitting Diode) or a laser.

[0048] The light IL emitted from the light emitting unit 70 passes through a window 150 provided in the parting portion 142 and enters the second portion 134 of the liquid crystal layer 130. The window 150 is provided in a through-hole formed in the parting portion 142. The window 150 is made of, for example, glass.

[0049] The wavelength of the light IL emitted from the light irradiating unit 70 is, for example, 400 nm or more and 490 nm or less, and preferably 420 nm or less. The wavelength of the light IL may be light in a shorter wavelength range than the blue light BL incident on the first portion 132. The light IL may be blue light or purple light. The light PL emitted from the liquid crystal degradation product 136 is light having a wavelength longer than that of the light IL. The intensity of the light IL emitted from the light irradiating unit 70 is, for example, lower than the intensity of the blue light BL incident on the first portion 132 of the liquid crystal layer 130.

[0050] The light detection unit 80 overlaps with the second portion 134 of the liquid crystal layer 130 when viewed from the normal direction. The light detection unit 80 overlaps with the light irradiation unit 70 when viewed from the normal direction. The light detection unit 80 is provided on the element substrate 110. The light detection unit 80 is provided, for example, on the side of the element substrate 110 opposite to the liquid crystal layer 130. In the illustrated example, the light detection unit 80 is provided on a surface of the element substrate 110 facing the -Z axis direction. The light detection unit 80 is, for example, a photodiode, a camera, a spectrometer, or the like.

[0051] A wavelength filter (not shown) may be provided between the light detection unit 80 and the liquid crystal layer 130. The wavelength filter reduces light between 400 nm and 600 nm, for example. The wavelength filter can reduce the amount of light IL that enters the light detection unit 80. The wavelength filter may also completely cut off the light IL.

[0052] The detection result of the light detection unit 80 is transmitted to the control unit 90. The display device 100 includes, for example, the control unit 90. The control unit 90 is configured to include, for example, an integrated circuit (IC). The control unit 90 acquires a detection signal from the light detection unit 80. The control unit 90 performs processing to determine the degree of deterioration of the liquid crystal panel 32 based on the acquired detection signal. Specific processing by the control unit 90 will be described later.

[0053] 1.4. Changes in LCD panel performance over time and photoluminescence FIG. 6 is a graph illustrating the change over time in photoluminescence when blue light is irradiated onto a liquid crystal layer. In FIG. 6, the horizontal axis represents the measured wavelength, and the vertical axis represents the intensity observed in the liquid crystal layer irradiated with blue light. The solid line L0 represents the initial spectrum when blue light begins to be irradiated onto the liquid crystal layer, and the dashed line L1 represents the spectrum after blue light has been irradiated for a certain period of time. It is assumed that the spectrum other than that corresponding to the incident light is due to photoluminescence from degraded liquid crystal molecules, i.e., degraded liquid crystal molecules. FIG. 6 and FIGS. 7 to 9, described below, show cases where both blue light and photoluminescence are detected.

[0054] As shown in Figure 6, when a liquid crystal layer is continuously irradiated with blue light having an intensity peak around 450 nm for a certain period of time, the intensity of the spectrum of the emitted light from the liquid crystal layer increases. In particular, the intensity in the wavelength band between 550 nm and 650 nm increases, and the emitted light is observed as light with an increased proportion of red components. When electrons transition between liquid crystal molecules, a certain amount of light is emitted, but if liquid crystal molecules that have been degraded by photochemical reactions or other factors are present, it is estimated that emitted light includes phosphorescence with a wavelength of 550 nm to 650 nm.

[0055] 7 and 8 are graphs illustrating the change in photoluminescence over time in an accelerated aging test of a liquid crystal panel. FIG. 7 shows spectra at test times T0, T1, T2, T3, and T4, respectively. In FIG. 7, the horizontal axis represents the measured wavelength, and the vertical axis represents the light intensity observed on the liquid crystal panel. FIG. 8 shows the change in light intensity over time in the 500 nm to 650 nm band. In FIG. 8, the horizontal axis represents the test time, and the vertical axis represents the light intensity observed on the liquid crystal panel. FIG. 8 shows points corresponding to test times T0, T1, T2, T3, and T4 shown in FIG. 7. In the accelerated aging test shown in FIGS. 7 and 8, blue light with a high luminous flux density was irradiated onto the liquid crystal panel, and the liquid crystal panel was observed from the light incident side.

[0056] 9 is a graph for explaining the electro-optical characteristics (VT characteristics) of a liquid crystal panel. In FIG. 9, the vertical axis represents the transmittance, and the horizontal axis represents the voltage applied to the liquid crystal panel. In FIG. 9, The VT curves of the liquid crystal panel corresponding to test times T0, T3, and T4 are shown, respectively.

[0057] The main factor for the change over time of the light intensity observed in the liquid crystal panel is the change over time of the photoluminescence intensity of the liquid crystal panel. The test time T0 indicates the initial state, and T0 < T1 < T2 < T3 < T4. By irradiating with blue light, the intensity of the spectrum of the emitted light due to the photoluminescence of the liquid crystal increases. At test times T1 and T2, in the wavelength band from 500 nm to 650 nm, the intensity of the photoluminescence from the liquid crystal panel increases. At test times T3 and T4, furthermore, the intensity of the photoluminescence in the entire measured wavelength range increases, and the intensity of the photoluminescence in the wavelength band from 500 nm to 650 nm increases significantly. The test times T3 and T4 are 1.1 times and 1.2 times the time of the test time T2, respectively. The intensities of the photoluminescence at test times T3 and T4 are 1.5 times and more than 3 times the intensity of the photoluminescence at test time T2, respectively. The V-T curve of the liquid crystal panel at test time T3 changes in the dark direction, and the V-T curve of the liquid crystal panel at test time T4 changes in the bright direction, and the display quality of the liquid crystal panel deteriorates. It can be seen that the deterioration of the liquid crystal panel progresses rapidly from test time T3. Therefore, the deterioration of the liquid crystal panel can be grasped by the change in the intensity of the photoluminescence of the liquid crystal panel.

[0058] In addition, it is presumed that the factor for the increase in the intensity of the photoluminescence of the liquid crystal panel is the increase in the concentration of deteriorated liquid crystal molecules. After test time T4, the liquid crystal molecules deteriorate further, and the liquid crystal panel can no longer recover the display quality even with correction or the like, and the life of the liquid crystal panel comes to an end. As a determination of the life, for example, as shown in FIG. 8, the time point when the intensity I0 of the photoluminescence observed between test time T2 and test time T3 is detected is determined to be the life of the liquid crystal panel. The intensity I0 of the photoluminescence can be set to the limit value I0 corresponding to the liquid crystal panel.

[0059] Therefore, by detecting the intensity of photoluminescence emitted from the liquid crystal panel, it is possible to monitor the deterioration of the liquid crystal layer and the deterioration of the liquid crystal panel caused by the deterioration of the liquid crystal layer. When blue light is continuously irradiated onto the liquid crystal for a certain period of time, the light emitted from the liquid crystal panel also contains fluorescent light with a wavelength of 600nm to 650nm. Furthermore, the shorter the wavelength of light irradiated onto the liquid crystal, the more likely it is to deteriorate due to photochemical reactions, etc.

[0060] 1.5. Control Method Next, a control method for the display device 100 according to the first embodiment will be described with reference to the drawings. Specifically, the processing of the control unit 90 of the display device 100 will be described. FIG. 10 is a flowchart for explaining the processing of the control unit 90.

[0061] The control unit 90 starts processing when a signal to start processing is input via an operation unit (not shown).

[0062] First, as shown in FIG. 10, the control unit 90 controls the light irradiation unit 70 to irradiate the liquid crystal layer 130 with light IL, and performs a process of detecting the light PL emitted from the liquid crystal degradation material 136 of the liquid crystal layer 130 due to the irradiation of light IL via the light detection unit 80 (step S1).

[0063] Next, the control unit 90 performs a process of determining whether or not the intensity of the detected light PL exceeds a predetermined value (step S2). The predetermined value may be set in consideration of the limit value I0 shown in FIG.

[0064] If it is determined that the intensity of the light PL does not exceed the predetermined value ("NO" in step S2), the control unit 90 returns the process to step S2. Then, steps S1 and S2 are repeated until it is determined in step S2 that the intensity of the light PL exceeds the predetermined value.

[0065] On the other hand, if it is determined that the intensity of the light PL exceeds the predetermined value ("YES" in step S2), the control unit 90 performs a process of notifying the user of the lifespan of the liquid crystal panel 32 (step S3). Specifically, the control unit 90 performs a process of notifying the user that the liquid crystal panel 32 has reached the end of its lifespan or the time remaining until the end of its lifespan. The means of notification is not particularly limited. For example, after receiving the notification from the control unit 90, the user performs maintenance on the liquid crystal panel 32.

[0066] Then, the control unit 90 ends the process.

[0067] If it is determined that the intensity of the light PL exceeds a predetermined value, the control unit 90 may perform a correction process to make the intensity of the light PL equal to or less than the predetermined value. For example, the control unit 90 may send a control signal to the light source 10 to reduce the output of the light source 10. For example, reducing the output of the light source 10 can buy time until maintenance by the user is required.

[0068] 1.6. Effects The display device 100 includes a light source 10, an element substrate 110 as a first substrate and an opposing substrate 140 as a second substrate arranged opposite each other, and a liquid crystal layer 130 arranged between the element substrate 110 and the opposing substrate 140, and a liquid crystal panel 32 having a display area 2 into which light emitted from the light source 10 is incident and a peripheral area 4 around the display area 2, a light irradiation unit 70 that irradiates light IL in a first wavelength range onto a second portion 134 that is a portion that overlaps with the peripheral area 4 of the liquid crystal layer 130 when viewed from the normal direction, and a light detection unit 80 that detects light PL in a wavelength range longer than the first wavelength range that is emitted from the second portion 134 of the liquid crystal layer 130 when light IL in the first wavelength range is irradiated onto the second portion 134 of the liquid crystal layer 130 by the light irradiation unit 70.

[0069] Therefore, in the display device 100, light suitable for detection can be emitted from the light irradiator 70 compared to detecting light PL emitted by light emitted from a light source. For example, the intensity of the light IL emitted from the light irradiator 70 can be made smaller than that of the light emitted from the light source 10. This allows deterioration of the liquid crystal panel 32 to be detected efficiently.

[0070] In the display device 100, the light emitting unit 70 and the light detecting unit 80 overlap with the second portion 134 of the liquid crystal layer 130 when viewed from the normal direction. Therefore, the display device 100 can prevent light emitted from the light source 10 from entering the light detecting unit 80. This allows deterioration of the liquid crystal panel 32 to be detected with high accuracy.

[0071] In the display device 100, the light irradiating unit 70 is provided on the element substrate 110 on the opposite side to the liquid crystal layer 130, and the light detecting unit 80 is provided on the counter substrate 140 on the opposite side to the liquid crystal layer 130. Therefore, compared to when the light irradiating unit and the light detecting unit are provided on the liquid crystal layer side, for example, the influence of the provision of the light irradiating unit 70 and the light detecting unit 80 on the liquid crystal layer 130 can be reduced.

[0072] Although not shown, the light emitting section 70 may be provided on the element substrate 110, and the light detecting section 80 may be provided on the counter substrate 140. In this case, the element substrate 110 serves as the second substrate, and the counter substrate 140 serves as the first substrate.

[0073] 1.2. Display Device Modifications Next, a display device according to a modification of the first embodiment will be described with reference to the drawings. Figure 11 is a cross-sectional view that schematically shows a display device 200 according to a modification of the first embodiment.

[0074] Hereinafter, in a display device 200 according to a modification of the first embodiment, components having the same functions as the components of the display device 100 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0075] 5, in the display device 100, the light emitting section 70 is provided on the element substrate 110 on the opposite side to the liquid crystal layer 130. The light detecting section 80 is provided on the counter substrate 140 on the opposite side to the liquid crystal layer 130.

[0076] 11, in the display device 200, the light emitting section 70 is provided on the liquid crystal layer 130 side of the element substrate 110. The light detecting section 80 is provided on the liquid crystal layer 130 side of the counter substrate 140.

[0077] The light irradiation unit 70 is provided, for example, between the first support substrate 112 and the first alignment layer 118. The light detection unit 80 is provided, for example, between the parting portion 142 and the insulating layer 143. The parting portion 142 does not have a window portion 150.

[0078] In the display device 200, the light irradiator 70 is provided on the liquid crystal layer 130 side of the element substrate 110, and the light detector 80 is provided on the liquid crystal layer 130 side of the counter substrate 140. Therefore, in the display device 200, the distance between the light irradiator 70 and the liquid crystal layer 130 and the distance between the light detector 80 and the liquid crystal layer 130 can be made smaller than in, for example, the display device 100. This allows for accurate detection of deterioration of the liquid crystal panel 32. Furthermore, because the light irradiator 70 and the light detector 80 do not form the external appearance of the liquid crystal panel 32, design constraints imposed by providing the light irradiator 70 and the light detector 80 can be eliminated.

[0079] 2. Second embodiment 2.1. Display device Next, a display device according to a second embodiment will be described with reference to the drawings. Fig. 12 is a plan view schematically showing a display device 300 according to the second embodiment. Fig. 13 is a cross-sectional view taken along line XIII-XIII in Fig. 12, schematically showing the display device 300 according to the second embodiment.

[0080] Hereinafter, in the display device 300 according to the second embodiment, components having the same functions as the components of the display devices 100 and 200 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0081] 4 and 5, in the display device 100, the light emitting section 70 is provided in the liquid crystal layer 130 of the element substrate 110. The light detecting section 80 is provided on the counter substrate 140.

[0082] In contrast, in the display device 100, as shown in FIGS. 12 and 13, the light irradiator 70 and the light detector 80 are provided on the element substrate 110. In the example shown in FIG. 13, the light irradiator 70 and the light detector 80 are provided on the side of the element substrate 110 opposite the liquid crystal layer 130. The distance between the light irradiator 70 and the light detector 80 is preferably short. The light irradiator 70 and the light detector 80 may be in contact with each other. When viewed from the normal direction, the light detector 80 is provided, for example, closer to the display region 2 than the light irradiator 70. No window 150 is provided in the parting portion 142.

[0083] Although not shown, the light receiving surface of the light detection unit 80 may be tilted toward the light irradiation unit 70. This allows for efficient detection of light PL. Furthermore, the light irradiation unit 70 may be provided closer to the display region 2 than the light detection unit 80.

[0084] In the display device 300, the light irradiating section 70 and the light detecting section 80 are provided on the opposite side of the element substrate 110 from the liquid crystal layer 130. Therefore, in the display device 300, the light irradiating section 70 and the light detecting section 80 can be arranged more easily than when the light irradiating section and the light detecting section are arranged on separate substrates.

[0085] Although not shown, the light emitting section 70 and the light detecting section 80 may be provided on the counter substrate 140.

[0086] 2.2. Display Device Modifications Next, a display device according to a modification of the second embodiment will be described with reference to the drawings. Figure 14 is a cross-sectional view that schematically shows a display device 400 according to a modification of the second embodiment.

[0087] Hereinafter, in a display device 400 according to a modification of the second embodiment, components having the same functions as the components of the display devices 100, 200, and 300 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0088] In the display device 300 described above, the light emitting section 70 and the light detecting section 80 are provided on the side of the element substrate 110 opposite to the liquid crystal layer 130, as shown in FIG.

[0089] 14, in the display device 400, the light emitting unit 70 and the light detecting unit 80 are provided on the liquid crystal layer 130 side of the element substrate 110. The light emitting unit 70 and the light detecting unit 80 are provided between the first support substrate 112 and the first alignment layer 118, for example.

[0090] In the display device 400, the light emitting unit 70 and the light detecting unit 80 are provided on the liquid crystal layer 130 side of the element substrate 110. Therefore, in the display device 400, similar to the display device 200, the distance between the light emitting unit 70 and the liquid crystal layer 130 and the distance between the light detecting unit 80 and the liquid crystal layer 130 can be made small.

[0091] 3. Third embodiment 3.1. Display device Next, a display device according to a third embodiment will be described with reference to the drawings. Figure 15 is a plan view schematically showing a display device 500 according to the third embodiment.

[0092] Hereinafter, in the display device 500 according to the third embodiment, components having the same functions as the components of the display devices 100, 200, 300, and 400 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0093] 15, the display device 500 differs from the above-described display device 100 in that the display device 500 includes a first light guiding section 72 and a second light guiding section 82. Furthermore, the display device 500 includes, for example, a first light collecting section 74 and a second light collecting section 84.

[0094] The light irradiator 70 is separated from the liquid crystal panel 32. The first light guide 72 guides the light IL emitted from the light irradiator 70 to the second portion 134 of the liquid crystal layer 130. In the example shown, the first light guide 72 connects the light irradiator 70 and the first light collector 74. The first light guide 72 is an optical fiber.

[0095] The first light concentrator 74 overlaps with the second portion 134 of the liquid crystal layer 130 when viewed from the normal direction. The first light concentrator 74 is provided on, for example, the counter substrate 140. The first light concentrator 74 concentrates the light IL emitted from the first light guide 72 toward the second portion 134. Specifically, the first light concentrator 74 concentrates the light IL emitted from the light exit surface of the first light guide 72 toward the second portion 134. The first light concentrator 74 is, for example, a concentrating lens.

[0096] The second light collecting portion 84 overlaps with the second portion 134 of the liquid crystal layer 130 when viewed from the normal direction. The second light collecting portion 84 overlaps with the first light collecting portion 74 when viewed from the normal direction. 4 is provided on, for example, the element substrate 110. The second light collecting section 84 collects the light PL emitted from the second section 134 toward the second light guiding section 82. Specifically, the second light collecting section 84 collects the light PL emitted from the second section 134 toward the light incident surface of the second light guiding section 82. The second light collecting section 84 is, for example, a collecting lens.

[0097] The light detection unit 80 is separated from the liquid crystal panel 32. The second light guiding unit 82 guides the light PL emitted from the second portion 134 of the liquid crystal layer 130 to the light detection unit 80. In the example shown, the second light guiding unit 82 connects the second light collecting unit 84 and the light detection unit 80. The second light guiding unit 82 guides the light PL collected by the second light collecting unit 84 to the light detection unit 80. The second light guiding unit 82 is an optical fiber.

[0098] The display device 500 has a first light guiding section 72 that guides light IL in the first wavelength range emitted from the light irradiating section 70 to the second section 134 of the liquid crystal layer 130, and a second light guiding section 82 that guides light PL in the long wavelength range emitted from the second section 134 of the liquid crystal layer 130 to the light detecting section 80. Therefore, in the display device 500, the light irradiating section 70 and the light detecting section 80 do not need to be directly disposed on the liquid crystal panel 32, thereby increasing the degree of freedom in design.

[0099] The display device 500 includes a first light concentrator 74 that concentrates light IL in the first wavelength range emitted from the first light guiding section 72 toward the second portion 134 of the liquid crystal layer 130, and a second light concentrator 84 that concentrates light PL in the long wavelength range emitted from the second portion 134 of the liquid crystal layer 130 toward the second light guiding section 82. Therefore, the display device 500 can efficiently cause light IL in the first wavelength range to enter the second portion 134, and can efficiently cause light PL in the long wavelength range to enter the second light guiding section 82.

[0100] Although not shown, both the first light collecting section 74 and the second light collecting section 84 may be provided on the element substrate 110, or both the first light collecting section 74 and the second light collecting section 84 may be provided on the opposing substrate 140.

[0101] 3.2. Display Device Modifications Next, a display device according to a modification of the third embodiment will be described with reference to the drawings. Figure 16 is a plan view schematically showing a display device 600 according to a modification of the third embodiment.

[0102] Hereinafter, in a display device 600 according to a modification of the third embodiment, components having the same functions as the components of the display devices 100, 200, 300, 400, and 500 described above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0103] As shown in FIG. 15, the display device 500 includes the first light guiding section 72, the second light guiding section 82, the first light collecting section 74, and the second light collecting section 84.

[0104] 16, the display device 600 has the first light guiding section 72 and the first light collecting section 74, but does not have the second light guiding section 82 and the second light collecting section 84. Note that the display device 600 may have the second light guiding section 82 and the second light collecting section 84, but may not have the first light guiding section 72 and the first light collecting section 74, as shown in FIG.

[0105] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0106] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations that have the same functions, methods, and results, or configurations that have the same purpose and effects. The present invention also includes configurations that replace non-essential parts of the configurations described in the embodiments. The present invention also includes The present invention includes configurations that have the same effects as the configurations described in the embodiments or that can achieve the same purpose as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments.

[0107] The following can be derived from the above-described embodiment and modifications.

[0108] One aspect of the display device is A light source and a liquid crystal panel having a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel including a display area into which light emitted from the light source is incident, and a peripheral area around the display area; a light irradiation unit that irradiates a portion of the liquid crystal layer that overlaps with the peripheral region when viewed from a normal direction of the first substrate with light in a first wavelength range; a light detection unit that detects light in a wavelength range longer than the first wavelength range that is emitted from the portion of the liquid crystal layer when the light irradiation unit irradiates the portion of the liquid crystal layer with light in the first wavelength range; It has.

[0109] According to this display device, deterioration of the liquid crystal panel can be detected efficiently.

[0110] In one aspect of the display device, The light emitting section and the light detecting section may overlap the portion of the liquid crystal layer when viewed from the normal direction.

[0111] According to this display device, it is possible to prevent light emitted from the light source from entering the light detection section.

[0112] In one aspect of the display device, the light irradiation unit is provided on the opposite side of the first substrate to the liquid crystal layer, The light detection section may be provided on the second substrate on the opposite side to the liquid crystal layer.

[0113] According to this display device, the influence of the light emitting unit and the light detecting unit on the liquid crystal layer can be reduced.

[0114] In one aspect of the display device, the light irradiation unit is provided on the liquid crystal layer side of the first substrate, The light detection section may be provided on the liquid crystal layer side of the second substrate.

[0115] According to this display device, the distance between the light emitting section and the liquid crystal layer, and the distance between the light detecting section and the liquid crystal layer can be reduced.

[0116] In one aspect of the display device, The light emitting section and the light detecting section may be provided on the opposite side of the first substrate to the liquid crystal layer.

[0117] According to this display device, the light emitting unit and the light detecting unit can be easily arranged.

[0118] In one aspect of the display device, The light emitting section and the light detecting section may be provided on the liquid crystal layer side of the first substrate.

[0119] According to this display device, the distance between the light emitting section and the liquid crystal layer, and the distance between the light detecting section and the liquid crystal layer can be reduced.

[0120] In one aspect of the display device, a first light guiding section that guides the light in the first wavelength range emitted from the light emitting section to the portion of the liquid crystal layer; a second light guiding section that guides the light in the long wavelength range emitted from the portion of the liquid crystal layer to the light detecting section; may have

[0121] This display device allows for greater freedom in design.

[0122] In one aspect of the display device, a first light collecting section that collects light in the first wavelength range emitted from the first light guiding section toward the portion of the liquid crystal layer; a second light collecting section that collects the light in the long wavelength range emitted from the portion of the liquid crystal layer toward the second light guiding section; may have

[0123] According to this display device, light in the first wavelength range can be efficiently incident on the liquid crystal layer, and light in the long wavelength range can be efficiently incident on the second light guiding section.

[0124] One aspect of the control method for a display device includes: A light source and a liquid crystal panel having a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel including a display area into which light emitted from the light source is incident, and a peripheral area around the display area; a light irradiation unit that irradiates a portion of the liquid crystal layer that overlaps with the peripheral region when viewed from a normal direction of the first substrate with light in a first wavelength range; A method for controlling a display device having When the light irradiation unit irradiates the portion of the liquid crystal layer with light in the first wavelength range, the light irradiation unit detects light in a wavelength range longer than the first wavelength range that is emitted from the portion of the liquid crystal layer.

[0125] According to this control method for a display device, deterioration of the liquid crystal panel can be detected efficiently. [Explanation of symbols]

[0126] 2...display area, 4...peripheral area, 10...light source, 20, 22...dichroic mirror, 24, 26, 28...reflection mirror, 30R, 30G, 30B...light modulation device, 32...liquid crystal panel, 34...first polarizing element, 36...second polarizing element, 40...cross dichroic prism, 50...projection device, 60...screen, 70...light irradiation section, 72...first light guiding section, 74...first light collecting section, 80...light detection section, 82...second light guiding section, 84...second light collecting section, 90...control section, 100...display device, 101...external connection terminal, 102...data line driving circuit, 103...inspection circuit, 104...scanning line driving circuit, 105...first wiring, 106...second wiring, 110...element substrate, 112...first support substrate, 114...pixel electrode, 116...TFT, 118...first alignment layer, 120...sealing material, 130...liquid crystal layer, 132...first portion, 134...second portion, 136...liquid crystal deterioration product, 140...counter substrate, 141...second support substrate, 142...partition portion, 142a...inner edge, 143...insulating layer, 144...counter electrode, 145...second alignment layer, 150...window portion, 200, 300, 400, 500, 600...display device

Claims

1. A light source and a liquid crystal panel having a first substrate and a second substrate provided opposite to each other, and a liquid crystal layer provided between the first substrate and the second substrate, the liquid crystal panel including a display area into which light emitted from the light source is incident, and a peripheral area around the display area; a light irradiation unit that irradiates a portion of the liquid crystal layer that overlaps with the peripheral region when viewed from a normal direction of the first substrate with light in a first wavelength range; a light detection unit that detects light in a wavelength range longer than the first wavelength range that is emitted from the portion of the liquid crystal layer when the light irradiation unit irradiates the portion of the liquid crystal layer with light in the first wavelength range; A display device having:

2. In claim 1, The display device, wherein the light emitting unit and the light detecting unit overlap the portion of the liquid crystal layer when viewed from the normal direction.

3. In claim 2, the light irradiation unit is provided on the opposite side of the first substrate from the liquid crystal layer, The display device, wherein the light detection unit is provided on the second substrate on the opposite side to the liquid crystal layer.

4. In claim 2, the light irradiation unit is provided on the liquid crystal layer side of the first substrate, The display device, wherein the light detection unit is provided on the liquid crystal layer side of the second substrate.

5. In claim 2, The display device, wherein the light emitting unit and the light detecting unit are provided on the opposite side of the first substrate from the liquid crystal layer.

6. In claim 2, The display device, wherein the light emitting section and the light detecting section are provided on the liquid crystal layer side of the first substrate.

7. In claim 1, a first light guiding section that guides the light in the first wavelength range emitted from the light emitting section to the portion of the liquid crystal layer; a second light guiding section that guides the light in the long wavelength range emitted from the portion of the liquid crystal layer to the light detecting section; A display device having:

8. In claim 7, a first light collecting section that collects light in the first wavelength range emitted from the first light guiding section toward the portion of the liquid crystal layer; a second light collecting section that collects the light in the long wavelength range emitted from the portion of the liquid crystal layer toward the second light guiding section; A display device having:

9. A light source and a display region including a first substrate and a second substrate disposed opposite to each other and a liquid crystal layer disposed between the first substrate and the second substrate, the display region receiving light emitted from the light source; a liquid crystal panel having a peripheral area around the display area; a light irradiation unit that irradiates a portion of the liquid crystal layer that overlaps with the peripheral region when viewed from a normal direction of the first substrate with light in a first wavelength range; A method for controlling a display device having A control method for a display device, which, when light in the first wavelength range is irradiated to the portion of the liquid crystal layer by the light irradiation unit, detects light in a wavelength range longer than the first wavelength range that is emitted from the portion of the liquid crystal layer.

Images